The screw-sloop Marion, last wooden ship of the “Old Navy” on the Asiatic Station.
Rear Admiral David B. Harmony, who had last served in the Far East seventeen years earlier, remained at Yokohama only until the Alliance could be summoned to convey him to Hong Kong. To his embarrassment, his temporary flagship grounded on the submerged end of a breakwater while standing out in clear weather, a mishap later attributed to her navigator’s color blindness. Tugs working nearby came to her assistance, as did the commanding officer of HMS Mercury, who brought an anchor and a cable in his steam launch, and the Alliance was floated without damage at high water.
Harmony ordered the Marion, which had spent her entire six months on the station riding at anchor off Yokohama, to Nagasaki for docking and then to Chemulpo. The Alert was kept at Kobe and the Alliance at Nagasaki, both ready for sea at short notice although active cruising was limited by a Bureau of Equipment directive that coal consumption be kept to a minimum. The Monocacy remained on the Yangtze, where she was joined in April 1892 by the steel gunboat Petrel, another of the vessels of the “new” Navy. Called the “baby battleship” because of her heavy armament—four 6-inch guns, of which two could bear on any target—the Petrel was handicapped by her 11-knot speed and poor performance under sail. Nonetheless, she was to spend the next twenty years on the Asiatic Station, with time out for brief periods on Bering Sea patrol.
The Palos, the squadron’s lame duck, was still on the Pei Ho, and Lieutenant Commander John C. Rich reported that her boilers could no longer produce enough steam to turn her engine. Noting that a vessel so decrepit ought never to have been sent to the Pei Ho, the admiral ordered the Marion to tow her to Nagasaki for survey as soon as the danger of storms on the Yellow Sea had passed.
Almost immediately upon hoisting his flag, the new commander in chief began to receive reports pertaining to the situation along the Yangtze. He was not especially concerned, holding that American business interests in China were almost entirely in the hands of foreign and Chinese merchants, none of whom could claim the protection of the United States, and that American-flag shipping had almost disappeared from Chinese waters.
The protection of missionaries, however, was his responsibility, and the missionary community was hardly insignificant in terms of numbers. The treaties forced on China in 1858 and 1860 had introduced religious toleration to that nation, and the thirty years following had brought a steady increase in Christian missionary activity. By 1890, there were 513 American missionaries representing nineteen denominations in China; only the British supported a greater number. And, while foreigners generally resided at one or another of the relatively few treaty ports, missionaries were wont to range far into the hinterland “only controlled by their own interpretation of the wishes of the Almighty.”1 Thus, to afford them even a modicum of protection taxed the resources of naval officers, many of whom undoubtedly agreed with the Monocacy’s Commander Francis M. Barber that all entitled to and claiming the U.S. government’s protection should be brought more directly under that government’s control.
But 1892 was a quiet year throughout the Orient. Even Korea was so tranquil that the State Department agreed that a warship need not be kept at Chemulpo. The Marion, which towed the Palos to Nagasaki in mid-June, thereafter cruised in northern Japanese waters, and the Alliance sailed for Mare Island in August. A few weeks earlier, the Palos’s fate had been decided by a board of survey which found that thorough repair of her hull and machinery would require expenditures far beyond the old gunboat’s worth. Admiral Harmony recommended that she be decommissioned and sold. The Navy Department concurred, so the veteran Palos, literally worn-out after twenty-two years on the Asiatic Station, was stripped of usable fittings and sold for scrap on 25 January 1893.
The spring of 1893 found Admiral Harmony concerned about the Chinese reaction to exclusion legislation recently passed by the U.S. Congress. Considering the Yangtze Valley the area most likely to experience anti-foreign turbulence, he assigned the Marion, Monocacy, and Petrel to spend the summer shuttling between Shanghai and the river’s treaty ports, while the Alert in Japanese waters would respond to developments elsewhere on the station. The admiral himself was nearing the statutory retirement age, so the Lancaster steamed to Yokohama to await his relief, Rear Admiral John Irwin, who assumed command of the Asiatic Squadron on 7 June.
Irwin’s tenure of command was uneventful and unexpectedly brief. The Petrel was ordered to the Bering Sea for the summer, and the Alert departed for San Francisco in mid-August. The steel gunboat Concord, larger and faster than the Petrel, was en route to the station, and the protected cruiser Baltimore was under orders to relieve the aged Lancaster, so the commander in chief could look forward to a proper flagship. These vessels had yet to reach the station when, on 11 October, Admiral Irwin received a confidential telegram informing him that he was to be relieved of his command on 27 October, on which date he and his staff would take passage in the mail steamer to Honolulu, there to hoist his flag in the protected cruiser Philadelphia as commander in chief of the Pacific Squadron. A day earlier, somewhat similar orders had been sent to Acting Rear Admiral Joseph S. Skerrett, commander in chief of the Pacific Squadron, who was to take Irwin’s place.
Such a “swap” of commands was not usual for the U.S. Navy, and it obviously requires some explanation. For this, one must look to Honolulu where, a few months earlier, a bloodless revolution had occurred. The last Hawaiian monarch, Liliuokalani, had been dethroned by American Hawaiians who seem to have triumphed mainly because of the presence of the U.S. cruiser Boston, which landed an armed force ostensibly to protect American interests. A provisional government, quickly formed and as quickly recognized by the U.S. minister, sent commissioners to Washington to arrange American annexation of the islands. A treaty to this end was drawn up and signed without difficulty, but the Senate delayed action on it at the request of President-elect Grover Cleveland. After his inauguration, Cleveland withdrew the treaty and ordered an investigation, which revealed that native Hawaiians generally preferred the deposed queen. The provisional government, however, refused to give way, nor would American opinion permit the use of force to restore a monarch. Thus, Hawaii remained independent under a government which intended that it become a part of the United States as soon as possible, while President Cleveland, who would not countenance annexation, was determined that foreign influence must not supplant that of his nation at Honolulu.
Admiral Skerrett had assumed command of the Pacific Squadron on 9 January 1893, one week before the Hawaiian revolution. Arriving in Honolulu soon after the event, he reported that the provisional government was incapable of gaining the public support necessary to win an election. His subsequent communications, however, indicated that Skerrett was being won over by that government, leading Navy Secretary Hilary A. Herbert to warn that his course should be one of complete neutrality toward both governmental and royalist factions. Soon thereafter, Skerrett managed to bring about the dispatch of a British warship to Hawaiian waters—which the United States was anxious to avoid—by indiscreetly telling the British minister that the vessels of the Pacific Squadron were not authorized to protect foreigners in the islands. This indiscretion, which the admiral himself reported, convinced Herbert that Skerrett must leave Honolulu. A simple removal from his command was out of the question, for the naval officer would almost certainly demand a court-martial which might be embarrassing to the government, so the secretary ordered him to exchange commands with the somewhat senior and presumably more perceptive John Irwin.
Joseph Skerrett, of course, was no stranger to the Far East, having commanded the flagship Richmond for some three years and served as the squadron’s senior officer after Peirce Crosby’s sudden departure in 1883. Skerrett hoisted his flag in the Lancaster on 9 December 1893, hoping perhaps that the Asiatic Station would prove a less taxing command than that which he had relinquished. However, it was not to be.
For a time, all went well. The Concord and the Petrel had reported for duty before the admiral’s arrival, and the Baltimore steamed into Hong Kong later in December. The Lancaster and the Marion, the last of the U.S. Navy’s old wooden warships to serve on the Asiatic Station, both departed in mid-February. The Lancaster, sailing from Hong Kong to New York by the Suez route, made a routine passage, but not the Marion.
The Marion stood out of Yokohama bound for Mare Island with fine weather and a fair wind. One day out, Commander Charles V. Gridley ordered her boiler fires burned down and her screw uncoupled. She made good progress under sail the next day, but on 22 February the wind increased gradually until it reached hurricane strength. The Marion was hove to under storm canvas, and boiler fires were lighted; but she labored so violently in mountainous seas that several boilers began to work loose in their saddles and all leaked badly. Water was pouring into the vessel through deck and side seams, while waves breaking on board carried away a boat and several gunport covers. Gridley had the prisoners released so that they could take a turn at the deck pumps, assist in the stokehold, or, if necessary, abandon ship. But the Marion and her men were equal to this occasion. The boilers were chocked in place, and half were made tight enough to provide steam to pumps and engines. Oil streamed from the weather bow exerted its calming effect on the troubled waters, lessening the impact of the waves. The gale diminished markedly the next day, and on 24 February Commander Gridley set a course for Yokohama, whence he reported that his vessel owed her survival to her own seaworthiness, adding that the service still had topmen capable of hazardous work aloft. After being docked and repaired, the Marion took her final departure from the station on 10 April.
“… 15.9.44. Now that the French Atlantic ports are no longer in our possession, U-boat operations will be continued from Norway. A few Home ports will also be used, since the Norwegian bases have insufficient accommodation, and operational possibilities will thus be limited. The Type IXC boats will no longer be able to operate either in the Caribbean or on the Gold Coast without refuelling, and will therefore be obliged to concentrate mainly on the US coast, the Newfoundland area and also the St Lawrence, which is again accessible to schnorkel boats. As a rule we shall be unable to use the Type VIIC boats in the Channel, since the passage takes so long that they would be unlikely to arrive in a fit state to operate under such difficult conditions; the only other areas remaining to them are the Moray Firth, the Minch and the North Channel in British coastal waters, and Reykjavik.
“It must be assumed that the enemy will concentrate his A/S forces off Norway, and in the Atlantic passage, North Sea and Baltic approaches. Theoretically, he can build up such heavy concentration in these regions that the old-type boats, which need to schnorkel fairly often, are bound to be located sooner or later and subjected to a concerted attack. Hence, if it were necessary to continue the campaign with these old types, the loss of the Atlantic bases would prove to be grave and decisive; but the new Type XXI boats, by virtue of their very great endurance, high submerged speed and deep diving capability, should be able to thrust their way through the enemy A/S concentrations to operate successfully both in the North Atlantic and in remote areas…”.
This brief statement outlined the U-boat situation as FO U-boats saw it at the beginning of October 1944, irrespective of the general course of the war; and in order to understand his apparent confidence in the future success of the new-type boats, it would be well at this point, to examine the provisions of the 1943 Fleet Building Programme, in so far as they affected the U-boat.
The U-boat building programme taxes German productive capacity
A major barrier to successful implementation of the overall U-boat building programme lay in a dual requirement for both rapid achievement of mass production of the new boats and maintenance of the rate of delivery of the older types, which necessitated provision of double the quantity of materials and manufacturing capacity over a transition period of from six to eight months. One of the prime essentials was to step up the production of U-boat batteries, and to achieve this in the short time available before the new boats began to arrive from the builders was the Armaments Ministry’s most difficult task; no plant for the manufacture of batteries existed in Germany itself, so it was necessary to produce the requisite machinery and equipment for this at the expense of current contracts, except those concerned with aircraft production, which had absolute priority. An additional problem, which at first appeared insoluble, was posed by the sheer quantity of lead and rubber needed for the batteries; but this difficulty was later overcome.
The new boats had also to be equipped with very powerful electric motors and a large number of other electrical fittings, such as cruising motors, trimming and bilge pumps, echo-ranging gear, underwater listening apparatus, radio and radar sets and radar search receivers, production of which engaged a considerable part of the whole German electrical industry and was only made possible by severe curtailment of such essential work as power-station and locomotive construction.
The provision of high-grade steel plate for the pressure hulls posed another difficult problem, for this commodity constituted the worst bottleneck in the whole of the steel industry and, since the old-type boats had still to be built and the new types required even more, demand for steel plate from the autumn of 1943 was three and a half times as great as the allocation hitherto. Furthermore, because of a heavy requirement for the repair of bomb damage to warships and local installations, the dockyards, already burdened with the expanded naval building programme, were now unable to cope with the shaping of pressure-hull sections, which had therefore to be delivered ready rolled.
The Chairman of the Central Shipbuilding Committee, Herr Merker, had taken on a difficult task. Considerable risk was involved in mass-producing a fundamentally new type of U-boat without trials, for if the boat proved to be a failure, the prodigious efforts of German industry would have been in vain and material allocated for the construction of 180 to 200 U-boats would have become so much scrap. Just as great a risk was involved in the introduction of prefabrication and mass-production methods into general shipbuilding; both methods were being applied for the first time to craft of considerable size under severe wartime conditions and against the advice of many experts, while those responsible were beset by the worry of completing the task at the earliest possible date. Nevertheless, contracts were placed with German yards for 360 Type XXI and 118 Type XXIII, and in the Mediterranean ports for 90 Type XXIII U-boats.
Prefabrication and mass production
The hull of the Type XXI U-boat was made up of eight separate sections – one section to a compartment – and these sections were constructed in 13 different yards, which allowed duplication and ensured that if a number of sections were destroyed in one yard a corresponding number of U-boats would not be lost. Nevertheless, the safety of the section-building and U-boat assembly yards was a matter of much concern, and in 1944 efforts were made to provide them all with bunker protection, a step already in hand at Hamburg-Finkenwerder and Bremen-Farge, with a few others being improvised elsewhere. The situation would have been less critical if section building could have been moved inland; but this was impossible as, owing to their size, the sections could only be transported to the assembly yards by water.
The actual building process was roughly as follows. A section-building yard was supplied first with, say, 40 similar part-sections of section 1 – the stern section of the boat – and delivery of the remaining part-sections was then timed to ensure the completion of the sections in sequence; thus, at any given time there would be 40 sections in progressive stages of assembly. The larger part-sections were machined and prepared for assembly on the actual site, while the smaller ones passed through the machine shops on the conveyor-belt principle. As soon as the first section had been assembled it was fitted with the appropriate machinery, electrical equipment, messing accommodation etc., the same operation on each section being performed by the same workmen for the sake of speed.
The delivery of the completed sections to the U-boat assembly yards at Bremen (Deschimag), Hamburg (Blohm & Voss) and Danzig (Schichau), and the process of final assembly and launching, all had to follow a strict time-table, and it is not surprising that difficulties arose in the early stages of the programme. The section-building yards were at first unable to keep to the schedule, partly owing to delayed delivery from subcontractors of certain important fittings and partly to the first part-sections having been badly rolled and exceeding the specified tolerances, which necessitated additional work. As a consequence, the supposedly complete sections for the first boats arrived at the assembly yards late and in an unfinished state, which in their turn meant additional work in the time allotted for U-boat assembly. The Central Shipbuilding Committee, however, would permit no postponement of U-boat completion dates and ruthlessly insisted on strict observance of the timetable. The first boats to be launched, therefore, had much work outstanding – and a lot that was, perforce, skimped – so that they had later to spend long periods in dockyard hands. Indeed, so many imperfections showed up in the first seven boats that they could be used only for training and experimental purposes.
All these difficulties, together with prevailing differences of opinion, caused tension and antagonism between the Central Shipbuilding Committee, the Naval Command and the dockyard authorities. This unfortunate atmosphere prevailed until the summer of 1944, when there was a noticeable improvement, due in part to the influence of the Shipbuilding Commission, which under Admiral Topp had been created at the beginning of that year, and which thereafter acted as mediator between the Naval Command and the Armaments Ministry on behalf of the Shipbuilding Committee.
The war ended before the Germans could deploy their own next wave of technology embodied by the Type XXI ”Electric” boat, with much larger battery capacity that gave it a fast underwater speed. Until late 1944 Allied bombing had a disruptive rather than disastrous impact on the Type XXI program. The situation changed radically in 1945 when massive raids resulted in the destruction not only of U-boats still on the ways but also of completed U-boats fitting out, or, in some cases, after commissioning and while undergoing training. Thus, quite apart from the damage to construction facilities, 17 completed Type XXIs were sunk in harbour between December 31, 1944 and May 8, 1945: Hamburg – seven; Kiel – six; and Bremen – four.
In essence the Type XXI simply introduced too much that was new simultaneously and demanded too much of those involved in the program. The reasons for this were diverse. In part it was due to the impending defeat on the high seas and the desire to do something – anything – to prevent it. There was also a fascination in Germany for anything that was new and militarily impressive. With hindsight, there also appears to have been an air of unreality about many activities and decisions, some of which may have been due to the pressure of work and others plain ‘woolly thinking’. Unfortunately for the Kriegsmarine, the outcome of all the pressure and cutting of corners was that the boats that were actually completed were constantly having to return to the yards for repair and modification, resulting in delays in attaining full-service stratus.
Delays in completion and training
Owing to the circumstances already mentioned, the whole U-boat building programme gradually dropped about five months behind schedule and, although the first Type XXI boat was launched as planned in April 1944, she was not commissioned until June. By the end of October, 32 Type XXI and 18 Type XXIII had been commissioned, while those under construction in the assembly yards were so far advanced that, even allowing for considerable destruction through bombing, a monthly delivery rate of 15 to 20 Type XXI and six to ten Type XXIII could be expected in the immediate future. German records do not show the exact number of new-type boats completed; but from the record of those commissioned, it can be seen that the expected rate was generally achieved.
As was mentioned, the unorthodox methods used in the construction of these boats was responsible for an inordinate number of defects in the first to commission, and frequent interruptions for repair and modification combined to lengthen the crew training period from the usual three months to nearly six. However, by dint of close co-operation between the Construction Office at Blankenburg, the U-boat Acceptance Staff and the Admiral in Charge of U-boat Training, the fundamental defects were eliminated within a few months and, from the autumn onwards, the necessary modifications were incorporated into all U-boats delivered from the builders.
A nucleus of experienced U-boat commanders and petty officers formed the backbone of the new crews, who buckled down to their training with great enthusiasm. Meanwhile, the U-boat Command, which had previously studied the question of tactical employment of the new-type boats, had passed on their findings to the training, experimental and trials staffs and to the U-boat commanders. It was thus possible to put the new theories quickly to the test and to incorporate suggested improvements, which thereby hastened the process of establishing a firm basis for both crew training and operational use of the boats. The final “Battle Instructions for Type XXI and XXIII U-boats” were compiled from the evaluation of extensive sea trials carried out in one boat of each type, commanded by two well-trained officers, Korvettenkapitän Topp and Kapitänleutnant Emmermann.
Outstanding fighting qualities of the new boats
During the first Type XXI trials run over the measured mile at Hela, it was at once evident that the designed submerged full speed of 18 knots for one hour 40 minutes would not be realised, the maximum submerged speed attained varying between 16 and \7\ knots for from 60 to 80 minutes. However, at medium speeds of from 8 to 14 knots the disparity between design and performance was not so great, and the cruising motors came up to expectations with a speed of 5 to 5.1 knots.
A boat proceeding on cruising motors had to schnorkel for three hours daily to keep her batteries fully charged, and at a submerged cruising speed of five knots she could thus traverse the danger area between the Norwegian coast and the south of Iceland in about five days, raising her schnorkel on only five occasions. The schnorkel head was fitted with a Tunis aerial and coated with sorbo rubber as a protection against radar, so the boats were less vulnerable to location and attack from the air than hitherto. Even if the schnorkel were to be located by radar – which by virtue of its absorbent coating was only possible at short range – a boat would be in no great danger, since a sharp alteration of course coupled with a large increase in speed would quickly take her clear of the area and out of range of the aircraft’s sonobuoys; she could then continue for as long as necessary at the silent running speed of five knots, at which it was possible to cover more than 300 miles, or at two to three knots, a speed which she could maintain for 80 to 100 hours without having to schnorkel. The new boats had, therefore, a much better chance than the old type of reaching the Atlantic unobserved.
The silent submerged cruising speed of 5 to 5.1 knots was also an excellent attack speed and, in the event that this proved too slow, a convoy attack could always be pressed home by using high speed. This capability and the newly introduced echo-ranging gear and plotting-table, specially designed for use in such attacks, gave the Type XXI a decisive advantage over the old schnorkel boats. Furthermore, the Torpedo Trials Staff had developed a special instrument for so-called “programmed firing” in convoy attacks: as soon as a U-boat had succeeded in getting beneath a convoy, data collected by echo-ranging was converted and automatically set on the Lut torpedoes, which were then fired in spreads of six, at five- and fifteen-second intervals. The torpedoes opened out fanwise until their spread covered the extent of the convoy, when they began running in loops across its mean course, making good a slightly greater or lower speed, and in so doing covered the whole convoy. In theory these torpedoes were certain of hitting every ship of from 60 to 100 metres in length; and the theoretical possibility of 95 to 99 per cent hits in an average convoy was, in fact, achieved on firing trails.
In addition to the Lut, an improved torpedo was now available which was capable of homing onto propeller noises and virtually immune to Foxer.
Even if she did not entirely fulfil our expectations, the Type XXI U-boat was an excellent weapon when assessed against the A/S capability prevailing in 1944. She had overcome her worst teething troubles; and it was our intention to use a few of these boats within the next four months to resume the battle both in the Atlantic and in remote areas, later disposing an increasing number to the west of the British Isles. By virtue of its great endurance, the Type XXI could reach any part of the Atlantic and remain there for three to six weeks; it could, in fact, have just made the passage to Cape Town and back without refuelling.
It was decided that any attempt at submerged pack tactics, with the support of air reconnaissance, should be delayed until sufficient boats became available; but communication requirements for cooperation between Type XXI U-boats and aircraft had been dealt with and the procedures exercised. For reconnaissance west of the British Isles, the Luftwaffe intended to provide Do 335 aircraft, which by reason of their high speed of 430 to 470 mph could fly direct across the United Kingdom at night. FO U-boats did not believe that sufficient aircraft would be made available for proper support in such operations, despite the Luftwaffe’s assurances; however, he was convinced that good results could be obtained without them, since the Type XXI required only one encounter with a convoy – particularly in a remote area – to fire all its torpedoes, with great prospects of attaining a number of hits.
The six SKJOLD Class FAC were built by Kvaerner/Umoe Mandal incorporating the SENIT 2000 combat management system as a joint development of DCNS (now Naval Group) and Kongsberg.
A view of Skjold, Gnist, Storm and Skudd operating together whilst on exercise in the Kristiansund at the end of January 2014. Skjold acted as the pre-production trials ship for the class design between 1999 and 2003, undertaking a lengthy deployment to the United States. She had only recently returned to operational fleet when this image was taken.
Kongsberg‘snew generation Naval Strike Missile [NSM] has been selected to equip the NANSEN and SKJOLD Class vessels of the RNoN as an anti-ship and land-attack missile. Future operators include Poland, Malaysia, the US and Germany.
With the re-delivery of the HNoMS Skjold on 29 April 2013, the Norwegian Navy finally has all six of its Skjold class fast attack craft in service. The Royal Norwegian Navy (RNN) has a long history of operating fast patrol boats, going back as far as 1873 when the steam-powered, Thornycroft-built Rap was commissioned into the fleet, placing the RNN in the forefront of fast patrol boat operators. Ever since then, fast patrol boats have been an integral element in Norway’s defence structure and the RNN has kept on refining the design of these vessels over time. However, they have never previously adopted a design as radical in so many ways as these latest ships.
The prototype Skjold class vessel has now been rebuilt to the standards of the production series. Most notably, she has acquired the revised COGAG propulsion system of two Pratt & Whitney ST18M and two Pratt & Whitney STM40 gas turbines fitted in the series-built vessels in replacement for her original CODOG propulsion system. A full outfit of weapons and sensors has also been installed. Re-commissioned in the Spring of 2013, this view shows her participating in the NATO Cold Response 2014 training exercise.
GENESIS: EVOLUTION OF THE SKJOLD CLASS
The origins of the Skjold programme date back to the mid-1980s, when the Norwegian Defence Research Establishment (NDRE) began to study a replacement for the Storm and, ultimately, the Hauk class fast attack craft, which were, respectively, commissioned into the fleet between 1965 and 1967 and between 1977 and 1980. The emerging programme for the new units, which ultimately came to be known as Project SMP 6081, required them to be survivable, stable weapons platforms capable of operating at speeds of 45 knots in Sea State 3, to have a range of at least 800 nautical miles at 40 knots, and to be able to operate outside coastal waters in a variety of scenarios, including NATO operations. In addition, the project office undertook a wide range of studies designed to reduce the vessels’ radar cross-section (RCS) and infrared (IR) signatures.
The Norwegian Navy Material Command (NAVMATCOM), together with Commander Sea Training (COMSEATRAIN), ran several analyses to balance the operational requirements with the likely available budget. For the platform system, no fewer than ten different platforms concepts were initially taken into consideration. Having examined this wide range of replacement options, the study was subsequently narrowed down to a shortlist of three concepts, viz. a conventional mono-hull, a catamaran-hull and an air-cushion catamaran/surface effect ship (ACC/SES).
The studies carried out by NAVMATCOM indicated that shock levels experienced by the SES were only one-third of that of a mono-hull.3 Similarly, the maximum displacement of structural members when subjected to shock was around half that of a comparable mono-hull. These advantages were a direct result of the SES’s elevated position in the water and its low draught. In spite of this, there was some hesitation in adopting the new hull form and a SES passenger vessel was even hired to uncover operational limitations of an SES when compared with the mono-hulled Storm and Hauk classes. Additional confidence was provided through experience gained designing and constructing the Oksøy and Alta class minehunters and minesweepers, which demonstrated the stability and large deck area inherent in the SES-catamaran hull form. Ultimately, the combination of improved resistance to shock and survivability, superior sea-keeping, greater internal volume and high speed-to-power ratio that the ACC/SES provided proved decisive in its selection.
By 1994 all staff requirements were defined and, in July 1995, a Request for Proposals [RfP] was issued. Three yards ultimately submitted bids: the Norwegian shipyards Umoe Mandal and Mjellem & Karlsen and Lürssen Werft in Germany. On 30 August 1996 Umoe Mandal was awarded a c. US$36m equivalent contract to build a pre-production unit, to be named Skjold. Following approval of construction specifications by NAVMATCOM, construction commenced in 1997. The prototype vessel was launched on 22 September 1998 and turned over to the Royal Norwegian Navy on 17 April 1999. At this stage weapons, sensors and combat management systems were not installed and 46 tons of sand ballast was subsequently provided to simulate their wight.
The pre-series vessel underwent comprehensive testing with focus on speed, sea-keeping, EMI/EMC, signatures and functionality, as well as the operational reliability tests – mainly in northern Norway during autumn and winter. There was also a year-long deployment to North America on loan to the US Navy. This initial trials programme had an important bearing on whether to proceed with the series production order and was to result in several changes to the production specification.
In spite of emerging doubts about the value of the programme in the post-Cold War naval environment, a new defence white paper approved by the Norwegian parliament in June 2001 envisaged the construction of five additional units. This decision was subsequently confirmed in October 2003 once terms and pricing for the programme had been provisionally agreed. Subsequently, on 28 November that year, the Material Investment Branch of Norway’s Defence Logistics Organisation (NDLO) awarded the Skjold Prime Consortium (SPC) a NOK3.7bn (c.US$550m) contract to build and equip the five new ships, whilst upgrading the prototype to the same standard. The SPC was an industrial alliance that brought together three partner companies to share responsibility for the delivery of the Skjold platform. It comprised Umoe Mandal (responsible for detailed design, systems integration, construction, testing and integrated logistic support); the Armaris joint venture between France’s DCN and Thales, now merged into DCNS (combat system design authority); and Kongsberg Defence & Aerospace (responsible for delivering and integrating the combat system in cooperation with Armaris). Umoe Mandal’s share of the programme consisted of about NOK2bn; Armaris received approximately NOK1bn; whilst Kongsberg Defence & Aerospace’s (KDA’s) share was valued at NOK750m. The construction of the first of the five standard production units, Storm, began in October 2005
In spite of further challenges to the class’s value and a number of project delays, commissioning of the new ships in operational configuration commenced in September 2010, with the re-delivery of the upgraded Skjold in April 2013 completing the programme. All units will achieve full operational capability by early 2015. It is the RNN’s plan to have four units available at any time, while two undergo maintenance and further upgrades.
DESIGN DETAILS: STRUCTURE AND STEALTH
The most distinctive feature of the Skjold class design is undoubtedly its innovative twin ACC hull form. The 47.5m long, catamaran SES-hull is made of a fibre reinforced plastic (FRP) sandwich construction, which reduces the overall weight of the ship. This material is capable of absorbing high levels of impact and, as such, minimising the extent of damage to the ship’s structure, as well as the cost of repairs. FRP also gives the ship so much buoyancy in itself that it can hardly sink. Moreover, its use enables most types of damage – from a surface scratch in the laminate through to major damage to a panel and its underlying structure – to be repaired quickly by using specially developed techniques. Another noteworthy feature is the provision of under-deck heating to prevent build-up of ice on the deck. Umoe Mandal was licensed to use the Seemann Composites Resin Infusion Moulding Process (SCRIMP) technique in constructing the class. This consists of a resin transfer moulding process that uses a vacuum to pull liquid resin into a dry lay-up. It is used for making very high quality, repeatable composite parts with almost zero VOC (volatile organic compound) emissions.
Stealth was a major preoccupation within the project office since the programme’s inception. The class has been designed to minimise all observable signatures. Controlled shaping of the ship above the waterline is evident in the absence of 90º corners and the inclination of the hull and superstructure at a small angle in order to deflect radar. The super-structure exhibits low and sleek characteristics, topside equipment is arranged to maximise concealment and there is extensive use of anechoic coatings. The air intakes to the gas turbines and lift fans are covered with a radar-absorbing mesh, the windows on the bridge incorporate a radar-absorbing material and all hatches are flush in order to reduce their RCS signatures. A similar consideration mandated the stealthy cupola provided for the Oto Melara 76mm/62 gun. The 9.6m-high main mast is constructed entirely from carbon fibre and the material is also used in beam flanges and frames.
Infra-red (IR) signature is kept to a minimum by the use of seawater cooling for the gas turbine exhausts; the water outlets are ducted into the air cushion between the two hulls and through the stern of the vessel. Similarly, the acoustic signature is decreased thanks to the fibre-reinforced plastic materials, which provide better structure-borne noise damping qualities. In addition, the water-jet propulsion generates lower hydro-acoustic signatures. The material composition in the wetted area of the twin hulls has been modified in order to produce a ‘smoother’ finish thus reducing hydrodynamic friction.
Operating in the littoral environment of fjords and archipelagos has also helped the Nordic navies become leaders in the application of present-day visual stealth and protective colourings. The Skjolds feature a camouflage scheme which is the result of the thorough study and testing of the hues and tones found in the Norwegian topography; scientists actually travelled around various areas and measured the colourings at different times of the year. The resulting paint scheme, which also incorporates high infra-red absorption properties, greatly reduces the ships’ electro-optical and visual signatures. As such, the Skjolds are hard to detect when lurking close to the coastline and are able to engage hostile forces from close range while remaining undetected. Another important asset is the class’s capability to access very shallow waters denied to other vessels. With about 75 per cent of their displacement being ‘carried on air’, a shallow draught of as little as 0.9m allows the ships to operate safely in shallow coastal waters whilst still maintaining excellent sea-keeping qualities.
A detailed view of Skudd’s bridge structure. A MASS decoy launcher is pictured in front of the bridge’s face, with the Saab CEROS-200 radar and optronic fire-control director mounted on the bridge roof. The carbon-fibre mast supports the Thales MRR-3D-NG multi-role radar on the lower platform, with a navigation radar above. The top of the mast houses the Sagem VIGY-20 electro-optical fire-control system with a pole for the ES-3701 ESM antenna immediately behind
PLATFORM MANAGEMENT SYSTEMS
The ships have been equipped with an advanced L-3 MAPPS integrated platform management system (IMPS) featuring multi-functional consoles with high-resolution colour monitors that display ergonomically designed graphical pages of the ship’s machinery and systems. This highly automated system incorporates an integrated bridge system (IBS) supplied by Kongsberg; a digital gas turbine control system; an integrated battle damage-control system (IBDCS); an equipment monitoring system (inclusive of a vibration monitoring capability); and a digital CCTV system. The overall system’s modular design, which combines widely distributed but intelligent and interconnected electronics, enables the crew to control, monitor and operate all platform machinery, electrical and emergency systems from several shipboard locations
The cockpit-style bridge, featuring a Kongsberg Maritime IBS, provides the pilot and navigator with full control over the bridge display consoles. It incorporates a K-Bridge autopilot, a voyage data recorder, a Kongsberg Seatex AIS 100 automatic identification system, an AGI electromagnetic log, a meteorological station, a Sagem 40 inertial navigation system, a Sperry Marine NAVIGAT 2100/SR 2100 fibre-optic gyro compass, a Trimble Navstar GPS/PPS receiver, JRC NAVTEX, a Skipper GDS 101 echo sounder and a Brudeseth optical bearing device. The bridge consoles display chart data from an Electronic Chart Display & Information System (ECDIS), radar and electro-optical (EO) data, as well as weapons system functionality.
Damage control is an important issue, with fire a principal concern. The RNN learned a lot of lessons from a catastrophic fire on board the Oksøy class minehunter Orkla in November 2002 and many of these have been incorporated into the Skjold class design. The ship is divided into six gas- and water-tight sections and features two engine rooms, one in each hull. The ship can continue to operate with one engine room out of action. Both are encapsulated with fire-retardant insulation material and incorporate Halotron and Hi-Fog water-mist fire-extinguishing systems. There is both a primary and secondary damage control station, both of which can access the IBDCS embodied in the L-3 MAPPS IPMS. This provides an instant overview of all aspects of the ship’s status and provides the opportunity to react in a very tight timeframe.
The Skjold class are equipped with primary and secondary machinery control rooms, which also act as the ship’s damage control stations. They provide access to the highly automated L-3 MAPPS integrated platform management system, which features a number of multi-function consoles and high-resolution colour screens, both pictured here. These allow the small crew to operate and monitor all the ship’s equipment.
The Skjold class was originally designed for a combined diesel or gas (CODOG) propulsion system. However, the RNN decided to change this to a combined gas and gas (COGAG) turbine configuration with two Pratt & Whitney ST18M and two Pratt & Whitney ST40M gas turbines driving two Kamewa 80S2 water-jets. Each hull has one propulsion train incorporating two gas turbines, a water-jet and a reduction gearbox. Adapting the ST18 and ST40 aircraft engines for use in a marine environment and the complexities of the associated COGAG layout proved to be a difficult process but was justified by the higher performance and better fuel economy offered across the full spectrum of different speeds and operating profiles. The ships have a range of 800 nautical miles at 40 knots and an endurance of around eight days. The reason for selecting water-jets as the main propulsion system was due to the combination of their favourable acoustic properties, low draught requirements and excellent manoeuvring capabilities.
Operation of the surface-effect air cushion is in the hands of a stabilisation system provided by VT Maritime Dynamics. This includes a ride control system that regulates the pressure of the air cushion between the two hulls that is created by a pair of 800kW lift fans driven by two MTU 12V 183 TE92 diesels in the bow. Flexible rubber ‘finger’ type seals in the bow and a ‘bag’ seal in the stern prevent air from leaking out of the cushion formed between the two side hulls. Vent valves and a seal management system in the stern, combined with a variable geometry inlet to the lift fans, control air flow and cushion pressure, improving the ship’s sea-keeping by minimising pitch and heave accelerations. The ability to manipulate the air cushion, combined with the water-jet propulsion, make the Skjolds both easy to handle and seaworthy. There is the option of choosing between speed and comfort, or a compromise. The class can maintain excellent sea-keeping qualities at 45 knots in Sea State 3 as well as achieving 60 knots in Sea State 1. The installation of a replenishment at sea (RAS) rig was approved following conclusion of a design review in mid-2012, offering the prospect of longer endurance.
COMBAT MANAGEMENT SYSTEM
The Skjold class is equipped with a SENIT 2000 combat management system (CMS) and associated KD2000 multi-function consoles. It is a derivative of the SENIT 8 system installed onboard the French aircraft carrier Charles de Gaulle. The SENIT 2000 CMS is, however, tailored specifically for coastal warfare, with emphasis on anti-surface weapons, passive detection, tactical data-links and fast response to ‘pop-up’ air threats.
Jointly developed by DCNS and Kongsberg, SENIT 2000 migrates existing functionality to a new open architecture that is based on PowerPC processors and the Linux operating system. It provides the ships with a processing capability comparable to that of a frigate. The CMS incorporates five consoles that feature a new generation of fully multi-functional LCD flat screen displays. This is claimed to be the first such application of this technology in a warship’s combat information centre.
SENIT 2000 performs all usual combat management functions, including the operation of weapons, sensors, data links and navigational equipment. It makes use of an extensive decision support system, capable of mission planning and execution, and of holding intelligence, cartography, Electronic Support Measures (ESM) and Electro-Optical (EO) databases. The system also includes extensive realtime recording and debriefing facilities, and provides comprehensive, on-board simulation and functionality for single operator, multi-operator, command and squadron level training. There is also, a sixth, additional console that has been provided for installation of a specific Norwegian command and control system.
Although originally classified as fast attack craft the Skjolds are now often referred to as ‘littoral combat corvettes’, due to their powerful combat suite. This reflects their primary purpose as fast anti-surface warfare platforms. For long-range engagement, the units rely on KDA’s Nytt Sjømals Missil (NSM) anti-ship cruise missile.6 The system consists of two quadruple launchers aft of the deck house, which elevate to fire and then retract to maintain the low RCS. The missile efflux is vented through an opening in the vessel’s stern. The missiles are equipped with a programmable intelligent multi-purpose fuze (PIMF) semi-armour piercing warhead of 120kg, GPS-aided mid-course guidance with an advanced dual-band imaging infrared (IIR) seeker for automatic target recognition. Range is c. 185km (100 nautical miles). Their digital flight control computer allows the missile to follow the complex contours of fjords before seeking its target. Their IIR-seeker detects, classifies and selects targets and, in its terminal approach, manoeuvres the missile randomly to defeat close-in defences. The NSM test firing and evaluation programme included a first firing at sea in October 2012 and a successful test against the target vessel Trondheim in June 2013.
The Skjolds mount a state-of-the-art communications system integrated by the German Aeromaritime group. Engineered to give an optimal solution in terms of communication performance and compactness, it includes HF, VHF and UHF radio links, as well as satellite communications, and supports NATO Link 11 and 16 connectivity. From mid-2014 onwards, the class is being equipped with the Thales’ SURFSAT-S satellite communication system, which includes connections with the Inmarsat and Iridium civilian networks as well as military satellites. The overall communications system allows class members to have a secure means of sharing an overall operational picture, thereby supporting closely entwined operations.
Operating the Skjolds is personnel-intensive. Although the IMPS and IBS provide a very high level of automation and make the performance of onboard tasks both accurate and easy, the carefully organised employment of every member of the crew is imperative in order to supervise and control the class’s systems effectively. Initially the ships were designed for a crew of sixteen but, after the lessons learned from Skjold’s deployment to the United States, it was decided to increase this to twenty-one.
As far as the accommodation is concerned there is one single cabin for the commanding officer; four double cabins for the other officers; and four-berth cabins for the petty officers and the ratings. Officers and petty officers share a wardroom while ratings have their own mess. There is a modern galley, two showers and two toilets. As no spare bunks are available, any additional personnel must sleep on improvised bunks in the wardroom or ratings’ mess. The RNN is studying possibilities to augment the number of crew because long-lasting high-intensity operations have proved to be very challenging. Commander sg Ståle Kasin – Commander Corvette Squadron Norwegian Navy – said that possible solutions could either be the introduction of ‘hot bunking’ or an increase the number of bunks: ‘Some of the cabins now have two bunks, so we’re looking into possibilities to install a third.’ During operations the crew can remain inside a nuclear-biological-chemical ‘citadel’ which encompasses the critical interior spaces, i.e. the crew’s quarters, the operations room and the bridge.
Upon the return from the United States, Commander Rune Andersen – Skjold’s commanding officer – confirmed that the living and accommodation standards were quite comfortable: ‘The interiors are spacious and comfortable. She has been our home for thirteen months now without problems. The staterooms provide comfort and privacy. We produce enough fresh water to shower and do laundry, the noise level is low and the temperature inside is nice no matter what temperature you find outside. She was just as comfortable in the Arctic waters as she was in the Caribbean.’
The Skjold class vessels have participated in a variety of exercises and activities. Each year they take part in Exercise Flotex: a Norwegian exercise conducted each November; in Exercise Northern Coasts: an exercise which takes place in Danish, Finnish, German or Swedish waters during September; in the Joint Warrior series off the west coast of Scotland and, every second year, in the NATO Exercise Cold Response. In addition to these manoeuvres the vessels have been taking part in a variety of smaller national exercises and operations, varying from support to the police and customs, to live missile firings and air exercises.
Skjold (P960): Launched on 22 September 1998, Skjold first commissioned into the RNN on 17 April 1999. She immediately started an intensive test period focussing on electromagnetic compatibility, signature reduction, speed and sea-keeping, as well as general arrangement and layout functionality. Just three days after her handover, she joined Exercise Blue Game 1999 alongside other fast attack craft from Denmark, Germany and Norway. Although not yet fitted with her weapons and weapon control system, it was essential for the RNN to try to operate the ship just like any other fast patrol boat. During the exercise Skjold crossed the Skagerrak six times, achieving a best average speed of over 50 knots. Upon completion of the exercise, she sailed to Oslo for demonstrations to the Chief of Defence, Minister of Defence and a number of politicians. After this, she sailed to her home base at Haakonsvern for the first time. Although experiencing conditions up to Sea State 5, she was still able to maintain speeds of 40–50 knots.
In August, KDA mounted two SENIT CMS multifunction consoles, after which Skjold sailed to Stavanger where an Oto Melara 76mm/62 Super Rapid gun was installed. In this configuration the ship attended to the DSEi-99 Exhibition in London. This was followed by test firings with the gun towards the end of September. The Millennium-year started with cold weather trials in the Tromsø and Skjervøy area (Finnmark) until end-February. This was followed by further firing tests with the main gun to measure strains on the hull and further extensive trials of all the ship’s systems and equipment. During one of these exercises Skjold pushed her top speed to 59.8 knots. The gun was removed upon completion of this trial period.
In March 2000 the US Navy Special Warfare Command personnel visited the ship to assess whether the high-speed design had any relevance to developing network-centric warfare concepts, including the Littoral Combat Ship (LCS) programme. This resulted in signature of an agreement between the US and Norwegian governments for the lease of Skjold for a twelve-month demonstration and evaluation program with the US Navy research establishments.
Prior to her departure to the United States, Skjold received a number of adjustments to her systems, including new navigation, radar, antenna and satellite equipment, as well as a device to handle US Navy type rigid inflatable boats (RIBs). The most obvious change, however, was a new colour scheme. The ship was repainted into lighter shades to reduce the surface temperature on the hull while operating in a warmer climate. Under the command of Commander Rune Andersen, Skjold departed Bergen on 4 September 2001. Calling at the Faeroe Islands and Reykjavik, she proceeded along Greenland’s eastern coast to the Eskimo village of Ammassalik. She then transited through Prince Christian Sound and called at Nanortalik and Cartwright, prior to reaching Corner Brook at the East Coast of Newfoundland. From here she sailed to Halifax, Newport, Rhode Island, and New York before arriving at the US Navy’s Amphibious Base in Little Creek, Virginia – her homeport for the next year – on 25 September. Here she became a fully integrated unit of Special Boat Squadron Two.
Skjold conducted an intensive trials programme whilst in the United States. She was used to assess the extent to which a high-speed platform of the type the ship represented could be used as a front-line ‘node’ in network-centric warfare and whether enhanced connectivity could enable such ships to undertake roles previously denied to them. The programme included simulated threats from air, surface and sub-surface sources; Special Forces and unmanned vehicle operations; and a range of instrumented tests encompassing sea-keeping, structural and signature performance. During this time, she was involved in a number of exercises. These included the mine-countermeasures focused GOMEX 02 in the Gulf of Mexico between 29 November and 14 December; and JTFEX 02-1 with the John F Kennedy (CV-67) Carrier Battle Group. Assigned to the opposition force, she reportedly managed to stay undetected and attack the aircraft carrier. Upon completion, she made several port calls in the Caribbean, conducting experimental training with the Naval Special Warfare Unit 4 SEALS Platoon at US Naval Station Roosevelt Roads, Puerto Rico. Returning to Little Creek at the end of May 2002, she participated in the Fleet Battle Experiment (FBE-J) and ‘Millennium Challenge’ exercises, followed by signature testing from airborne sensors and trials with a rig for replenishment-at-sea.
By mid-August preparations were underway for Skjold’s return trip to Norway. The homeward voyage saw calls at New York, Halifax, Cape Breton in Newfoundland, Labrador in Greenland, Reykjavik, Vestmannaeyar and the Faeroes. She arrived at Haakonsvern on 27 September 2002. The US deployment demonstrated the ship’s ability to be reconfigured quickly for disparate missions, to defend herself in a littoral environment and her suitability for Special Operations. However, the ship’s limited 800 nautical mile range was a drawback, in the US Navy’s opinion.
The RNN view was more unequivocally positive. Commander Andersen – Skjold’s first commanding officer – said, ‘She is extremely manoeuvrable and capable of maintaining high speeds in rough weather. The ship has met all the requirements laid down by the Norwegian Navy prior to her design. Since her commissioning in April 1999 she has impressed us with her high performance and high availability.’
Having served as the pre-production platform test bed for more than four years, during which she sailed some 85,000 nautical miles with high technical availability, Skjold was temporarily decommissioned on 24 June 2003. She returned to Umoe Mandal to be upgraded to final production standards and to act as training platform for the other units’ crews. She was re-delivered on 29 April 2013 and one of her first foreign visits took her to Rouen, France for the ‘Armada de Liberté’ in June 2013. This voyage was followed in November by exercise Flotex 2013. Subsequently, in 2014, Skjold took part in the Cold Response series and NATO’s Exercise Unified Vision 2014.
THE WAY AHEAD
The Skjold class is capable of contributing substantially to a wide range of operations in both the littoral and in blue water. Although designed to patrol Norway’s littoral waters, the units have already proved to be amongst the most flexible assets in the RNN. In particular, thanks to state-of-the-art communications and sensor suites, they are able to make a significant contribution to international operations. As demonstrated by Skjold’s deployment to the United States, even lengthy out-of-area deployments can be sustained and their top speed of 60 knots could prove quite useful to the EU or NATO counter-piracy operations. In short, Skjold and her sisters are rapid, powerful and inter-operable general purpose combatants that will be useful for a wide range of tasks.
Kongsberg’s Naval Strike Missile is operational on land and at sea. It can climb and descend according to terrain when it travels over land.
Norwegian Naval Strike Missile (NSM)
The Kongsberg NSM entered service with the Royal Norwegian Navy in 2012 and is employed by their SKJOLD class missile boats and FRIDTJOF NANSEN Class frigates. The first export order was received from Poland in 2008 for a coastal defence missile version of the system for the Polish Navy, with a second batch order being placed in late 2014. In 2015 it was announced that agreement over submarine acquisition between Germany and Norway, Kongsberg noted that: “Norwegian authorities announced that the strategic partnership for submarine acquisition expands to include Kongsberg’s Naval Strike Missile (NSM). The cooperation entails further development of the missile, and that the German navy intends to acquire a significant number of NSMs for its vessels. This also enables a close cooperation on joint maintenance and logistics between the German and the Norwegian navy.”
The NSM weighs 408 kg, travels at high subsonic speed, it uses a GPS/INS navigation system and has an imaging infrared (IIR) seeker with automatic target recognition, the warhead weighs 125 kg and its operational range is 185 km (range is dependent on flight profile). Emphasis has been put on signature reduction in the shaping of the missile and this is assisted by the IIR seeker being a passive system. There is also an air-launched version of the weapon known as the Joint Strike Missile (JSM), this has been designed to fit into the internal bays of the F-35 Joint Strike Fighter (JSF) that Norway is acquiring. Australia is said to be interested in the JSM for its future F-35 fleet.
Future developments of the NSM/JSM potentially include a version that can be launched from the MK 41 VLS and a submarine-launched variant. In terms of future export opportunities Kongsberg have been working to get involved in the US Navy OASuW programme. The NSM was fired from the USS Coronado (LCS-4) at Point Mugu, California, in July 2014. The ability to offer both NSM and JSM provides Kongsberg with tremendous export potential, in particular the ability to achieve internal carriage on the JSF could significantly expand the potential user base.
USS Greenfish (SS-351) after GUPPY III modernization. Visible on deck are the three distinctive shark-fin domes of the PUFFS sonar.
USS Piper (SS-409) with BQR-4A bow sonar
The Second World War had ended, and on the following March 6, 1946, Winston Churchill, the retired British prime minister, delivered a speech at Westminster College in Fulton, Missouri. In it he said, “An iron curtain has descended across the continent.” In so doing he not only described the state of hostility between America and Britain on the one hand and the Soviet Union on the other, he defined in one statement the future, four-decades-long power contest that was to embrace the military establishment of the United States.
During the war the mission of the American Pacific Submarine Force had been clear: sink Japanese ships. Having accomplished that formidable task, American submarines fell into a morass of uncertainty after the war ended. The later hulls were “mothballed” to spend their retirement years up the Sacramento River. Others were used as targets and met their fate in ignominious plunges to the bottom. Some friendly nations were rewarded with submarines, most of which were overhauled and brought up to near-perfect condition. In those years the submarine force struggled to find a new identity.
In the years immediately following the close of the Second World War, the submarine force continued to think in terms of attacking enemy surface ships. Friedman’s description of the era might be paraphrased as, “Submarine planners first denied that any change had to be made in submarine force doctrine. Then it entertained the possibility of change, but had no idea as what the future of submarines might be. Finally, it recognized its obligation to redefine the submarine’s mission in terms of Cold War realities.”
At the same time, American engineers were dissecting advanced German technology incorporated in the German Type XXI submarine. High-capacity batteries, hull design for great underwater speed, and the snorkel were only some of the Type XXI characteristics. The Germans had not conquered the difficulties of building a watertight telescoping snorkel, but this seemed to be the boat’s only shortfall. It was apparent to American engineers that the fleet-type submarine had to be modernized while a successor submarine was designed and built along the lines of the Type XXI. Any open conflict with Russia would be preceded by Soviet submarine incursions into American waters and in all probability in advanced submarines of the Type XXI quality.
The immediate postwar period was also marked by the formation of the Bureau of Ships, or BuShips. The Bureau of Construction and Repair had been staffed by naval architects, while the Bureau of Engineering had housed most of the Navy’s engineers. There had been a natural competition between these two aspects of submarine design since they tended to approach submarine innovation from the opposite direction. Architects centered their work on the theoretical factors of hull volume and weight to give the best possible submerged vehicle. Engineers were more practical. They added up all the equipment that would be needed to meet the demands of a reconstructed Cold War mission, then designed a platform to carry the underwater load. Engineers looked on the problem from the view of its many component parts. They saw the problem from the inside out and naval architects worked from the outside in.
While competition stimulated some vigorous work, such duplication could no longer be accepted in view of budgetary constraints. BuShips was confronted simultaneously with several design projects. The advent of the nuclear age was evident as civilian contractors visualized nuclear power plants as a means of cheap energy. The concept of nuclear propulsion for ships was a concept that could not be ignored by BuShips. If the Navy were to seriously engage in a long-range nuclear ship building program it would draw funds from the Type XXI postwar fast attack project. The many fleet-type boats resting in America’s rivers could be modernized to incorporate the innovations of the Type XXI design. BuShips then pushed ahead with three concepts: the nuclear ship; the Type XXI boat, to be called the Tang-class submarine; and the stopgap conversion of fleet-type hulls into Cold War–capability submarines.
It was clear to many in BuShips that if America was to build a nuclear reactor that could be a source of propulsion for Navy ships, the natural platform for such a reactor would be the submarine. A reactor that could provide heat for propulsion would not need oxygen as a constituent of fuel. It was obvious to Captain Hyman G. Rickover that the real future of American submarines lay in the development of a reactor that would be the foundation of a new class of true submersibles. Gaining the support of Congress to allocate significant funds for so radical an idea would take painstaking patience and determination. Rickover was single-minded as he assumed the lead in this effort. He was a naturally competitive naval officer and was willing to do whatever it would take to win. Captain Cutter described a fleet exercise in which fuel oil conservation was one of the competitive factors:
Take Rickover, Admiral Rickover. He was on the New Mexico as a lieutenant. Well, Rickover was doing his job. I mean it was dishonest. For the fuel situation he bribed the oiler who came alongside, gave him a bottle of booze or something so he would give the New Mexico 100 extra gallons and take them away from the next ship or something. Turned off all the lights and turned down the ventilators so people would be miserable, but it would save oil—anything to win that efficiency pennant for engineering. I don’t think Rickover did it for his career so much as the fact that he was a competitor, a great man. I have always admired that fellow. I don’t think we would be where we are today if it weren’t for him, in the nuclear power business.
For the United States Navy to embark on an experiment of such extravagant technical dimensions and at such huge cost required it to have a steadfast faith in the outcome. It would take a person of Rickover’s drive to stay at the helm through the manifold problems and to never let obstacles get in the way of the final goal—a submarine nuclear power plant for a breakthrough type of submarine.
But the transformation of the nuclear power concept into reality would take many years, and the Navy had to fill these years with a counter to the Soviet submarine threat. Thus, as work began on the nuclear power plant and the Tang-class boats were moving from the drawing board to shipyard construction, it was necessary to fill the gap with what the Navy had in its pocket: the fleet boats quietly resting in mothballs in the fresh water rivers of the United States. BuShips started with de-mothballing a series of Tench-class fleet-type boats. The superstructures were modified and streamlined by sloping the vertical plates to minimize deck width. The prow was rounded and an aluminum sail covered the conning tower and periscope shears. All guns and other deck equipment were removed or made flush with the deck. For example, the cleats were pivoted to fold into the deck. The battery was doubled in size from 126 cells to 252 cells, and a telescoping snorkel was inserted into the aft area of the sail. Twenty-seven tons of air conditioning and the elimination of the battery exhaust system helped in habitability. These features and others made up the GUPPY, acronym for Greater Underwater Propulsive Power.
During the 1950s, GUPPY submarines were stationed in Groton, Norfolk, Charleston, Key West, San Diego and Pearl Harbor. Each station had a designated submarine operating area. Some lucky boats had operating areas close enough to allow daily operations. The resulting overnight liberty was good for morale and these boats had brows bouncing as their crew members ran to 0800 quarters after overnight liberty. The ritual morning quarters lined the enlisted men on one side of the after deck and the officers on the other. A few short words from the captain and executive officer ended in, “Set the maneuvering watch, make preparations for getting underway.”
Norfolk submarines were not so fortunate since the distance through Hampton Roads to the operating area meant weekly operations: out on Monday mornings and in on Friday afternoons. On these Fridays competitive captains drove their boats on an all-ahead-full bell, the quicker to get home and the better to beat out rivals for coveted pierside berthing. Those in maneuvering added turns of their own as each boat raced from sea up the channel entrances to their respective tenders and piers. When close to the berth assignment, the captain entered the next phase of self-made competition. The number of maneuvering bells (changes in twin screw manipulation) was the subject of crew pride stemming from admiration of the captain. The “three-bell landing” was the best. It was forbidden to change from an ahead bell directly to a back bell. Such a command placed a hardship on the maneuvering watch while straining the main motors. This mistake marked the conning officer as an amateur and invited ridicule from other officers. Certainly, the captain was bound to order an “all-stop” bell before going to “all-back-full.” The boat would shudder as the propellers dug into the sea at full power. If the landing was perfect, the boat would come to rest alongside the pier with the final order, “All-stop. Secure main engines. Get over all lines.”
Pride in one’s submarine was built on such competence. Each crew member of each boat knew that his submarine was the best and that his responsibility was do his job to keep it that way. GUPPIES spent much time at sea diving, surfacing, snorkeling and conducting each exercise as expertly as possible.
The relationship of pride in one’s submarine and one’s job directly affected the proficiency of the fire control party. The GUPPY was the Navy’s workhorse during the decades following the Second World War, when the fire control problem shifted from periscope information to sonar-only information. The difficulty of submarine vs. submarine tactics demanded mathematically based analysis and innovative methods. Dedicated minds worked to improve the quality of undersea tactics.
The GUPPY assumed several roles in the 1950s and ’60s. It played the hostile submarine when providing services to ASW surface units, it performed sonar picket duties when operating as a part of a hunter-killer group, and it trained its crew in practice periscope and sonar attacks. It departed its home base to render services to Navy and Allied units in the Western Pacific, Mediterranean Sea, North Sea and other locations. Finally, of greatest importance, it conducted special operations, which involved surveillance of Soviet forces and installations. About every other year, the GUPPY had an overhaul at one of the Navy’s shipyards in addition to upkeep periods alongside its tender. This period was usually about six months in length and was intended to make major repairs and alterations in response to the ever-changing demands of the Cold War.
There were a series of improvements starting in the latter part of the 1940s and continuing into the 1970s. The GUPPYs continued as the workhorse of the submarine fleet even as nuclear powered submarines were entering service. The first of the series was the Odax (SS-484), a GUPPY I. Thereafter, modified fleet-type boats were put in commission as fleet snorkels, and GUPPY IIs. Special conversions included special BQR-4 bow-mounted sonars. These were to be used as listening posts at the ocean’s choke points.
The most prevalent modification was the GUPPY IIb with a step sail, chin-mounted BQR-2 passive sonar array, and deck-mounted transducer. In the mid–1950s fiberglass full sails called northern sails replaced the aluminum step sails. The GUPPY III offered improved bridge visibility, at the expense of increased underwater drag.
Sonar improvements concentrated on detection of modern Soviet submarines that were anticipated to represent improvements in the best German designs. Detection of hostile submarines would rely upon sonar as its primary source of target information. The periscope would become a secondary tool of torpedo fire control as the submarine’s primary mission was redefined as a member of an ASW group that included surface, air and undersea components.
The GUPPY JT sonar was a passive listening device not significantly different from its first installation in 1942. It was retained for a number of years as an additional passive sonar to the postwar BQR-2. The sonar head or hydrophone was approximately 5 feet in horizontal length and was located forward of the conning tower. It had a shaft that could be trained to locate the bearing of a sound source such as a ship’s propeller or submarine internal noises. American submarines would continue to use JT sonar with improved bearing deviation indicators which could detect surface ships at ranges approximating 4000 yards.
The Germans had used a passive array sonar called “Gruppenhorchgeraete,” which was a horseshoe-shaped array equivalent to a straight-line array.5 The GHG was installed on the converted American submarine Cochino (SS-345) in 1949. It formed the basis for further American sonar improvements during the 1950s, including a bearing deviation indicator with a radar-style plan position indicator. This improved sonar was mounted on the USS Clamagore (SS-343) in 1948. Further improvements in the array-type sonar resulted in the BQR-2. This version of the original German GHG had 48 vertical staves, each 3 feet long, in a 6-foot circular width housed in a 5-foot-high dome. The array operated at 150 Hz to 15 kHz. A later, improved model, the BQR-2b, had an improved display that included a bearing time recorder (BTR). A paper rolled down past the BTR stylus that moved horizontally, reflecting a full commutator scan. The BTR provided a record of the target’s motion as well as its bearing. This innovation was to have enormous benefit as a source of bearing change rate necessary for plot analysis.
In the early 1950s the Naval Underwater Sound Laboratory at New London worked on further improvements to the BQR-2b. By the end of the 1950s the renamed Naval Undersea Systems Center produced the BQR-5 and 6. These advanced passive sonar systems incorporated both detection and automatic target tracking.
The wardrooms of the GUPPY II type boats were modified in the 1950s to provide a makeshift attack center. Geographical plot and Ekelund ranging techniques were performed on the wardroom table while the opaque panel separating the wardroom from the passageway was replaced with a transparent plexiglass relative-bearing compass rose display. A quartermaster in the passageway kept a relative-bearing plot on the display and fire control communication linked sonar, the attack center and the conning tower. This system, as crude as it may sound by today’s standards, worked well, and each person in the fire control party performed specialized functions in relative comfort.
The wardroom navigational plot consisted of a dead reckoning tracer or DRT mounted into the eating table. It had a glass top through which could be seen a light point driven from the master gyro compass and pit log. A sheet of graph paper overlaying the glass top represented a geographical plot with automatic own ship inputs represented by the moving point of light. Above the dead reckoning tracer was a small repeater for target bearing and course information from the TDC.
The GUPPY II fire control organization was divided between the conning tower, wardroom and sonar space. With the TDC in the conning tower and the various bearings-only plots in the wardroom, communication and coordination were critical to smoothly functioning fire control. The system included a direct sound-powered telephone link between the plot coordinator in the wardroom and the assistant approach officer in the conning tower who monitored the set-up in the TDC and advised the approach officer of the best solution for target course, speed and range. The plot coordinator had another link with the sonar supervisor so that the wardroom acting as attack center became the crucial analysis station in submarine-versus-submarine sonar-bearings-only approaches. The role of the TDC became one of receptor of information coming from plot.
The GUPPY III conversion included a modification to accommodate the ever-more-complex demands of expanded fire control equipment and organization. One of the four engines was removed to make room for the pumping equipment that was formerly located in the pump room below the control room. The vacated space below the control room became the attack center where various plots were managed in the bearings-only fire control analysis. Because the periscope wells occupied the center of the pump room, the location was far from ideal as a dedicated fire control space. The dimensions of the Mark 101 fire control console made it impractical to place it in the pump room. Additionally, the captain, acting as approach officer, was committed to the conning tower. As a result, the ultimate GUPPY III conversion lengthened the conning tower to accommodate the Mark 101 fire control console as well as its associated sonar display. The final version of the modification included an outsized fiberglass sail that reduced underwater speed.
Most GUPPY IIs used the wardroom as an attack center with the eating table converted to accommodate a DRT from the master gyro (Submarine Research Center).
Any sound can be analyzed into components by centering on different frequencies. A truly random signal carries all frequencies at about the same level of amplitude, but screw and equipment noise displayed a distinctive spectrum or signature on sonar screens. For example, a snorkeling submarine produced a strong signal at a discrete frequency from emitted noise of combined engine vibration and screw cavitation. If the pattern of a noise source was traced by stylus on a uniformly moving roll of graph paper, the sonar operator could examine the narrow spikes and determine the nature of the noise source. The pattern was referred to as a signature because it was consistently distinctive. Even a submerged submarine running on the battery would emit a signature noise, although much less apparent. This noise would be represented by a mix of flow noise over the submarine’s hull, noises from inboard piping, screw cavitation and pumps.
GUPPY III conversions initially used the pump room as an attack center by removing an engine and placing the pump equipment in the vacated space. Some conversions removed both engines in the after engine room and placed the fire control plots in the vacated space (Submarine Research Center).
Low-frequency components of sound can travel great distances through the sea without serious distortion. The sea produces a variety of ambient noises and the sonarman had to know these sounds in order to eliminate them as potential contacts. Shrimp make a clacking noise like fans at a football game and whales sing songs of long-distance romance. In addition, one’s own submarine makes abundant noise that had to be filtered out in the receptors and minds of the sonarmen. Bow plane noise was the most egregious and its placement in future submarine design would become a subject of concern. Sonar operators prided themselves on being able to identify the noise pattern of a specific submarine, even through all the background interference. Soon, the Navy’s sonar schools were training sonarmen to recognize the noise patterns of the various Soviet submarines.
Sonar could provide a reasonably accurate estimate of target speed. The sonar operator counted the rhythmic beat of a target ship’s screw, which indicated the speed of the propeller, the probable size of ship being driven by it, and the most probable speed of the ship through the water. Operators became proficient at this analysis and comparison sound tables were at hand to match target sound with known profiles.
The time-bearing plot furnished valuable information for other plots requiring accurate estimates of bearing change rates. The plot was a board upon which bearings were marked against their corresponding times. When sonar reported an initial bearing drift, bearings along the abscissa were noted at specific bearing intervals. The times of sonar-reported bearings (normally at four-minute intervals) were noted along the ordinate of the plot board. A mark was placed where the two intersected. As multiple contact reports from sonar were plotted, they emanated from the lower portion of the plot, starting with the time of the first reported sonar bearing. Since sonar bearings were not without error, it was necessary to reduce the bearing errors to as close to zero as possible. This was accomplished graphically to obtain the best indication of target bearing change rate. Straight-line fairings indicated a constant bearing change rate from which other plots could estimate target range, knowing target speed. The time-bearing plot could also signal possible changes in target speed or course or both when the array of time-bearings bent downward or upward.
One of three true bearing indications told the approach officer the relative movement caused by own ship’s course and speed and those of the target:
The time-bearing plot can illustrate target motion changes (speed and/or course) and can assist in estimating range (Submarine Research Center).
1. If true target bearing was drawing toward the bow, own submarine was losing true bearing and the target would pass ahead.
2. If true target bearing was drawing toward the stern, own submarine was gaining true bearing and the target would pass astern.
3. If true target bearing was remaining constant, the lead angle was correct and the submarine was closing the target.
Within the limits determined by target speed and course, the submarine could control the rate of true bearing change by changing own speed and lead angle; however, the submarine had only a limited amount of control over the change in true bearing, since its own speed depended on battery state, need for silent running and sea temperature/salinity condition. The optimum tactic by a submarine, particularly early in the approach, was to maintain a steady bearing or nearly steady bearing, to ensure closing the target to an effective weapon range.
Running in parallel to the time-bearing plot, another team of plotters used the same sonar bearings at discrete intervals to geographically trace the progress of bearing drift. The bearing drift appeared as spokes in a wheel. Lieutenant Joseph Ekelund and his colleagues saw that with an accurate target speed ruled as distance on a plastic strip, the plotting party could align the strip with bearings in such a manner as to match the ruled marker with bearing progression. This was done by sliding the strip up and down the most recent bearing, assuming a 90-degree angle-on-the-bow, then tilting the strip at various ranges to see if the ruled speed marks would align with previous bearings. In so doing, target angle-on-the-bow would be shown, target course could be derived and range estimated. It was not an exact science, but successive attempts resulted in surprisingly accurate information, particularly when in the hands of plotters who were willing to trust the method. As the plot continued, the initial estimate could be verified to eliminate other possible matches. The Ekelund “speed strips” method was simple in the extreme, but surprisingly effective at a time when electronic computers were far in the future.
Normally, the optimum firing point for the bearings’ only problem was about the same as for the normal periscope attack, with the exception that a greater stress was placed on obtaining near-zero gyros, optimal track angle and a short torpedo run to reduce the effect of not having a perfect solution. Optimum track angles produced a minimized effective target length. The shortest possible torpedo run reduced the affect of inherent errors.
The Ekelund plot depended on accurate sonar bearings taken at consistent intervals. Sonar accuracy was seldom as vivid as portrayed above (Submarine Research Center).
Whether the plots were run in the wardroom, pump room or engine room, the accuracy of problem analysis depended on the acuity of sonar bearings and the ability of sonar operators to identify the unknown submerged vessel as a Soviet submarine, and if so, the type of submarine with corresponding screw noise signature. If bearings could be pinpointed and if the screw noise signature could be correctly identified, the sonar operator had a good chance of obtaining an accurate turn count on the screw noise. He then could enter the turn count into his ship/submarine turn count conversion tables and render a probable target speed.
Target speed was reported to the sonar supervisor, who integrated the information with any other data at hand and told the plot coordinator the best target speed. At precise time intervals target bearings were reported and plotted. An Ekelund plot might appear as follows:
In this example, the listening submarine is on course 080 and the 8.5 knot speed strip reflects sonar’s best estimate of target speed. The grid of the strip aligns with the timed bearings to indicate a target course of 150, range about 4200 yards. Were this an actual approach and the target positively identified as hostile, the captain would either attempt to receive from ComSubLant or ComSubPac approval to begin a tracking mode or would have standing orders relevant to the situation. The captain, acting as approach officer, would be thinking of his TDC set-up (and later the Mark 101 set-up) in relation to the possible use of a Mark 37 torpedo.
During the Second World War the Mark 28 electric torpedo was an alternative to the straight-running, steam-propelled Mark 14 torpedo. Also during the war a purely defensive weapon, the Mark 27, had several unique features. It was the submarine’s first swim-out torpedo. With longitudinal guide rails and a small diameter, the torpedo was pushed silently out of the tube by its propeller. The torpedo then followed a pre-set course to a point where its passive sonar was activated. It was an excellent evasion maneuver weapon. The Mark 37 torpedo design was largely based on the concept of the Mark 27.
In the bearings-only attack, the Mark 37, Mod 4 torpedo was the weapon of choice. The optimum firing point would be reached when the target was within the Mark 37 torpedo’s enabling range of between 600 and 3,100 yards. The standard firing point thumb rule was 2500 yards. Target angle-on-the-bow at time of firing should not have been more than 60 degrees. The Mark 37 torpedo was a relatively slow electric torpedo and a large track angle indicated a probable divergent target course, with accompanying probability of the target outrunning the Mark 37’s capacity to close the target. An angle-on-the-bow of less than 60° at time of firing and a range of 2500 yards or less would maximize the chances of the torpedo’s acoustic acquisition. With a target submarine at a range of over 4000 yards, but with plot showing range decreasing and bearings reasonably constant, the captain would simply stay on course until the target was within range.
Once the torpedo had been launched, the submarine had to take evasive action on the assumption that own ship might be in the cross hairs of the target submarine. The captain knew the condition of his battery, which dictated how much speed he could use in an evasive maneuver. He balanced speed with cavitation noise emission at his depth and normally descended to find a positive gradient. Soviet ASW tactical doctrine of the 1950s called for use of active sonar much more abundantly than did American doctrine. If a Soviet submarine or surface vessel used active sonar in an attempt to locate the attacking submarine, the captain’s best chance of hiding was to get under a layer. The following diagram illustrates the evasion maneuver.
The effectiveness of active sonar to detect an evading submarine is often thwarted by some form of a positive gradient found in about 75 percent of ocean strata. The best depth for a submarine attempting to avoid detection by active sonar above a layer was to descend as quickly as possible. The avoidance of passive sonar was to maintain a slow speed to avoid cavitation. Avoidance of active sonar was to continually present a bow-on or stern-on aspect to the estimated bearing of the hostile submarine and to descend to a depth well below the positive gradient shown on the BT.
If the hostile submarine dove below the layer depth, the evading submarine could ascend above it and thereby remain hidden from active sonar (Submarine Research Center).
The evading submarine had a variety of maneuvers and tools at hand. The simplest was to release a mass of bubbles while turning the submarine and changing depth. This was the knuckle. At least one innovative boat found that by putting an electric razor to the UQC microphone, the sound in water was strikingly similar to an electric torpedo. This technique was intended to intimidate a hostile boat, but it never saw action against a Soviet submarine. The evasion arsenal included such tools as false-target canisters which could be ejected from the pyrotechnic ejector in the after torpedo room. These were used as the source of bubbles when performing a knuckle. The evasion weapon of last resort was the Mark 27 torpedo, normally carried in the after tubes. This torpedo was only 7 feet, six inches in length and 19 inches in diameter. As described above, it was swim-out launched by having a smaller diameter with guide rails that matched the 21-inch tube diameter. Its run was gyro controlled on a specified course, at the end of which its rudder assumed control, turning the torpedo in a wide circle. When its passive sonar detected a sound source it attacked that source.
While these measures could be deployed, the evading submarine’s best initial tactic when sensing that a hostile submarine had detected its presence was to go to ultra-quiet. Each compartment had a silent running bill and an ultra quiet running bill. In the latter, all machinery and pumps were shut down with the bow and stern planes being shifted to hand power. When such a condition lasted for several hours the planesmen became so exhausted that they would be relieved by off-watch planesmen.
During the 1950s the Navy renewed its effort to silence its submarines. Sound isolation of equipment became the focus of each yard overhaul. Running the diesel engines while snorkeling put so much sound in the water that shore-based low-frequency installations could monitor snorkeling boats as they transited the Atlantic. Neoprene engine mounts were inserted and experiments were conducted to suspend engines within soundproof boxes. Each line carrying fuel, water, hydraulic fluid and electrical conduiting had flexible inserts to reduce machinery vibrations entering the hull. While improvements were made in sound emission control, the GUPPY boats could not overcome the cavitation of the traditional four-bladed screw. Crews relied upon simple solutions: shut down every piece of non-vital equipment, reduce speed and go deep. During a submerged encounter with a Soviet submarine, crew members talked in whispers.
In 1946, the Bureau of Ordnance contracted with Arma Corporation for the design and development of an integrated torpedo fire control system which would augment the capacity of the torpedo data computer Mark IV.
It is difficult, in an age when a computer can be held in the palm of one hand, to visualize the difficulties of engineering a computer when electronics consisted of vacuum tubes and wiring. The evolution of the modern computer, when it is reversed, starts with micro chips the size of a pinhead, chips the size of a postage stamp, circuit boards with transistors and finally vacuum tube-driven monsters the size of a living room. In 1946 computers were made of syncro-servo units, tiny motors driving gears and mechanical displays that required considerable interpretation.
The new system was to incorporate concepts which evolved out of long wartime use of the TDC. Ideas presented to Arma Corporation by experienced submarine officers included an analyzer that could produce a quick, initial target solution, reduction of hand-inserted data with accompanying automation of target data assimilation, and automatic shift of torpedo ballistic data for mixed torpedo loads. Torpedo officers saw the need for electrical transmission of tactical data to tube-loaded torpedoes. The spindle-set torpedo required a mechanical connection with the torpedo tube so that point-of-fire information could be relayed to the torpedo. Experienced submarine officers knew that as torpedoes became more sophisticated, more inputs would be required. As the number of spindles increased, the greater complexity meant greater chances of malfunction. Spindle retraction time would be increased even if all systems worked properly. The mechanical transfer of information had to be replaced by electrical connections. This concept became a necessity when the Mark 37 torpedo’s design demanded instantaneous multiple inputs. Finally, there was the need for automatic torpedo firing and torpedo spread setting.
In 1913, Corbin, an authority on submarines at the time, predicted that submarine-to-submarine warfare would remain an impossibility. This opinion was to continue through the Second World War. In part, the opinion was predicated on the limitations of the steam torpedo. Also, sonar equipment prior to the Second World War could not furnish an accurate enough bearing to allow shooting a straight-running steam torpedo with any expectation of a hit. During the war, American submarines had sunk several Japanese submarines, but these attacks were periscope attacks against surfaced submarines. At the end of that war, a British submarine managed to accomplish the feat of hitting and sinking a submerged German submarine.
Arma Corporation tackled submarine officers’ tactical frustrations in a series of TDC improvements ultimately leading to a synthesized system designated the Mark 101 fire control system. It was augmented by the Mark 106 system, which provided for electrically fed inputs to torpedoes. The design of the Mark 101 system was grounded in the several innovative additions that were serially added to the TDC. A review of these TDC components illustrates the progression of bearings-only fire control equipment.
An initial addition to the TDC was a receiver section, which was physically located between the position keeper and angle solver. It received corrected sonar bearing inputs and furnished information to a sonar dial display together with other information such as observed optical bearing, radar bearing, and target range. The receiver section permitted inputs of searchlight sonar bearings to allow integrated best bearing information to the TDC.
The position indicator Mark 6 was the display unit of the receiver section. The main function of the position indicator was to display to conning tower personnel the fire control problem being solved by associated fire control equipment in the attack center of the submarine. The position indicator provided information as it was being received from various sources, the most important of which was sonar. The system also provided for a sound bearing converter that accommodated the difference between the speed of sound through water and the atmosphere.
Another addition was automatic screw noise baseline conversion in which a sonar baseline constant was permanently set into the TDC’s internal mechanism at the time of installation. From these inputs the converter continuously generated sonar baseline corrections, which were angle corrections to accommodate the difference in linear length from the location of a submarine’s screws to the middle of the target.
As the TDC improved system matured into a complete display of own ship movements, target movements and anticipated target turns, Arma engineers developed a console that would totally replace the TDC. The central function of the new Mark 101 display was the Mark 7 analyzer. It was basically an electric-mechanical navigational plotter. It received inputs of own ship’s motion with target ranges and bearings which were displayed together with target course and speed. The accuracy of the solution was dependent upon the accuracy of sonar bearing change rate; the greater the change, the more accurate the solution. The Mark 7 analyzer provided an end-point type of solution, which required a range and a bearing. Two observations were required and a time lapse between bearing change observations of about 90 seconds was required for a reliable solution. The drop-last feature could be utilized to increase the time between observations and could thereby refine the solution. The bearings-only type of solution was used when only target bearings were available. Bearing changes of at least 4.25 degrees were required for a reliable solution. After the initial solution based on three bearings was obtained, and subsequent bearings were entered, the drop-last feature could be utilized to refine the solution. The Mark 7 analyzer was helpful in obtaining quick solutions for target course depending on the reliability of inputs being used. Fire control personnel often used the Mark 7 solution as confirmation of plot-obtained information.
As the Mark 7 analyzer operator entered a series of three target bearings taken at equal intervals as described above, he adjusted estimated target range, course, and speed as further bearings became known. Initial estimates from plots could be integrated into the Mark 7 solution. The system’s analyzer could fit a straight-line constant speed track across the bearings. In effect, the Mark 101 system accomplished an Ekelund speed strip plot within its analog computing ability. The display information was still by dials, but the information was superior to that of the TDC even with multiple improvements.
The Mark 101 console was bulky and best suited to a dedicated space. Some GUPPY III conversions housed the massive console in an engine room which had been converted into an attack center by removal of the engines. The GUPPYs were stretched and pushed in experimental efforts to house the Mark 101/106 and sonar interpretation equipment.
The electric setting of tactical data into tube-loaded torpedoes from Mark 101 fire control solutions was accomplished by the Mark 106 system. The Mark 106 system also provided for tracking of multiple targets. This augmentation provided for more than one submarine in coordinated ASW attacks.10 Of course, the modification of torpedo tubes from spindle settings to electrical settings had to be accompanied by equivalent modifications of the torpedoes themselves. The conversion to electrically set torpedoes meant that complex information could be entered immediately prior to firing.
The finalized system was first installed aboard an operating submarine in 1951. Its central feature was a control console which provided for automatic shifting of spread order from right to left as changes in angle-on-the-bow moved from right to left and vice versa; automatic application of corrections to torpedo tactical data and automatic spread solution and application were inserted into the angle solver. The almost exclusive purpose of these sweeping improvements was to provide fire control capability against submerged submarines.
Since range continued to be a difficult problem even for the Mark 101 fire control system, the submarine force entertained the possibility of placing two hydrophones at the extreme ends of the GUPPY. The concept was simple. With a 300-foot separation, assuming a beam aspect to the target bearing, a triangulation of signal strength might produce a focal point (range) if the target was close enough to allow a signal comparison. To test the theory the Naval Ordnance Laboratory at White Oak, Maryland, used two modified JT hydrophone arrays mounted on the deck of a GUPPY submarine. One was mounted on the bow and the other at the extreme stern. This provided a triangulation of a submerged target at a range short enough to be computed by electronic trigonometry. The system was called “Passive Underwater Fire Control Feasibility Study, or PUFFS. Many GUPPYs of the late 1950s were equipped with PUFFS ranging equipment. Four of the Tang-class boats were also so equipped. These were all deck-mounted hydrophones which produced drag and were prone to environmental interference. The system was improved by moving the hydrophones into tanks, but the final designs on single-hull submarines had side-mounted passive sonar built into the basic structure of the hull.
In the early 1970s, a few Guppy III conversions, such as Tiru (SS-416), included a Mark 66 console for the newly-introduced Mark 48 torpedo. It used the BQS-4 azimuth range indicator. Another part of the system was a Mark 19 plotter for TMA estimates and PUFFS plotting. In these stretched conning tower conversions the PUFFS electronics BQG-4 display was installed. Also in a few attack center conversions were the BQS-4a and BQR-2b displays.
The GUPPY submarine also was America’s first attempt at electronic surveillance of Soviet communications. In the Atlantic, boats from New London and Norfolk put into Portsmouth, England, took on supplies, and headed north through the Irish Sea to the bleak and hazardous waters of the Barents Sea. On board were “spooks” from classified authority who carried black boxes as they crowded the radio space of the control room. Submarine captains received their orders from ComSubLant, who, when defining the special operation mission, tended to be a little vague as to respecting the international 12-mile limit. The Soviet Union claimed a 200-mile limit, which was ludicrous and therefore ignored. The trip was made through state five seas, and those on the bridge of step-sail GUPPYs were strapped to the TBT as the boat plunged through one wave and crested the next. The after room suffered from screws lifting out of water and vibrating their struts. At two-thirds on two engines using the raised snorkel and with the sea coming from off the bow, the submarines plowed their way forward on the surface.
One boat keeping to an eastward course rolled 102 degrees from a beam wave. It was saved by the helmsman, who acted quickly and without orders by putting the rudder hard over, bringing the boat’s bow into the sea. The submarine slowly righted itself, but the lookout and officer of the deck were drowned.
The USS Cochino was lost, and that story was told by Sherry Sontag and Chris Drew in their book, Blind Man’s Bluff. The following abbreviated description of the event has been taken from that book:
It was the need for stealth that convinced intelligence officials that submarines could be the next logical step in the creation of an eavesdropping network that would circle the Soviet Union. On its way to Murmansk the Cochino was rocked by waves as crewmen braced themselves, grabbing chart tables and overhead pipes. Others lunged to catch sliding coffee cups and tools.
“Cochino was running submerged on the snorkel, but the rough sea made the inherently tricky business of snorkeling impossible. The forward engine room reported that water was pouring into the submarine through the snorkel. The commanding officer sent his executive officer to investigate as the engines were shut down from lack of air. About two minutes later, there was a muffled thud and the submarine shuddered. An electrician saw sparks coming from the after battery compartment. He yelled for the compartment to be evacuated. Then, the commanding officer was informed of a fire in the after battery well. The submarine surfaced and was immediately swept by heavy seas. Another submarine, USS Tusk, in company with Cochino, was signaled by flashing light of the after battery fire and resulting casualties. Several crew members including the executive officer had been injured and remained in the after torpedo room of the submarine. All other crewmembers evacuated the after compartments to escape poisonous fumes. They crowded into the forward torpedo room.
The situation went from bad to worse as another crew member went over the side. After approximately two hours it became apparent to the captain that he would have to abandon his submarine. As fires raged below, USS Tusk came alongside. Cochino began to settle by the stern. A makeshift brow [gangplank] was cleated to both boats and Cochino crewmembers scrambled to the Tusk. Captain Benitez was the last person to leave his sinking submarine. The demise of Cochino was America’s introduction to the dangers of the Cold War.
During the 1950s some submarines were built and converted from fleet-type boats or GUPPYs in response to the need for sonar-specific missions. These included the K boats, which were small listening platforms designed only for sonar picket duty. Conversions from fleet snorkels or GUPPYs extended the bow to allow the larger BQR-4 array. These submarines played an important role in monitoring Soviet submarine transits.
GUPPY submarines were incorporated into ASW hunter-killer groups that included a helicopter-carrying aircraft carrier surrounded by a bent-line screen of ASW destroyers. In the van of these units were one or two submarines stationed about 20 miles ahead of the group. In addition, sonobuoy-equipped helicopters hovered on station in a 40-mile semicircle ahead of the main group. These units were very effective ASW threats to any Soviet transiting boats.
In the late 1950s, as an exercise test, a snorkeling GUPPY submarine zigzagged unannounced into an ASW hunter-killer search area. The submarine was detected at an estimated 23,000 yards. It was tracked by another GUPPY using only passive sonar, and the ASW submarine was able to close to a 2,000-yard range. The ASW submarine did not sight the target’s snorkel until just at the firing point. In another 1954 exercise off Iceland, the Cavalla, a converted SSK, simulated a transit to a forward base. The exercise called for the submarine K-1 to be the target and Cavalla the attacker. Both relied entirely on passive sonar. K-1 used the new Target Motion Analysis (TMA) technique and was able to successfully track Cavalla’s movements without Cavalla detecting K-1.
Yard overhauls with equipment and hull modifications kept pace with new sonar and fire control technologies for the duration of the GUPPY era. As described above, a ten-foot extension of the conning tower provided space for the latest TMA equipment, but there were limits to what a fleet-type hull could accommodate. Extension of the conning tower with added weight of equipment meant a higher center of gravity. The safety tank, which had been designed to counter the effect of a flooded conning tower, was rendered useless. The enormous sail produced additional underwater drag and its broad vertical face when on the surface invited heavy rolls in high winds and rough seas.
Some GUPPYs of the 1970s also had a Prairie-Masker system, which pumped bubbles into the screw blades’ leading and trailing edges. This system broke up the cavitation-producing collapsing bubbles, which quieted the boat when running at shallow depths.
The GUPPY program lasted for about twenty-five years, from the late 1940s to the late 1970s. As sufficient nuclear-powered submarines came into the fleet, the number of diesel-powered submarines dwindled. The transition from diesel-electric powered submarines to an all-nuclear powered submarine fleet may have covered over two decades, but the engineering effort to perfect a superior nuclear-powered attack submarine was multidimensional and complex in the extreme. The driving force of the transition was the Cold War evolution of mission definition, which demanded prolonged transiting at high speed and acquisition of submerged targets at great distances.
The Cold War was a race of technology between the United States and the Soviet Union. Each country tried to embarrass the other by attempting to force the opposite country’s submarines to the surface, thus exposing espionage efforts. It was commonly known, for example, that ComSubLant offered a case of Jack Daniels to the submarine that could force a Soviet Foxtrot boat to the surface. But, although the enthusiasm on both sides was extreme, the contest between the United States and the Soviet Union for world dominance never reached a level of open conflict.
As a result, sophisticated submarine torpedo fire control techniques, computers with high-speed TMA solutions, and the ability to diagnose noise signatures coming from opponents’ submarines never produced a single warshot torpedo fired from one submarine at another. It is remarkable that in 25 years of brinksmanship so intense that submarines were sunk, none did so from a torpedo attack. The casualties of the submarine Cold War resulted only from accidents in training exercises, equipment failures and aggressive surveillance collisions.
In a review of submarine torpedo fire control during the Cold War, it is appropriate to examine submarine development as a platform for torpedoes. Parenthetically, the decommissioning of the last diesel-electric powered submarine in the Navy’s fleet was later to bring about an unusual arrangement with a foreign nation.
Bogatyr Russian light cruiser class. Five protected, or 2nd Class, cruisers were ordered for the Imperial Russian Navy between 1889 and I90I. They followed the trend set by the Askold and Variag, being 23-knot ships of medium displacement and reasonable endurance for commerce-raiding.
The design was entrusted to the German firm of Vulkan, who built the lead ship and supplied material for another four to be built in Russian yards. They were unusual in being the first cruisers to have twin 6-in (152-mm) mountings, one forward and one aft, although the rest of the main armament was conventionally mounted in open-backed shields in broad-side sponsons.
The original intention was to build three ships for the Baltic and two for the Black Sea, but the Vitiaz caught fire during her construction and was so badly damaged that she had to be scrapped.
The Bogatyr helped to drive the German light cruiser Magdeburg ashore. 500 m (574 yards) from Odensholm lighthouse, on August 26. 1914. In November 1914 she was refitted for minelaying and on January 12, 1915 laid 100 mines east of Bornholm. A month later she was involved in a decisive action with the German cruiser München off Libau. In December, with her sister ship Oleg and the battleships Gangut and Sevastopol. she covered a minelaying raid east of Gotland and laid mines off Lyserort. One of her last operations before the Revolution was to cover a convoy with the big cruiser Rurik in June 1916. She was found to be in bad condition after the Revolution and the Civil War. and was stricken in 1922 and scrapped at Bremen.
The Oleg was interned during the Russo-Japanese war but returned to the Baltic after the end of hostilities in 1905. She was converted for minelaying in November 1914 and laid mines, in company with the Bogatyr. in January and February 1915. She was also involved in the skirmish with the Munchenon May 7. 1915 and accompanied her sister ship in most of the operations of 1915-17. She became part of the Red fleet in 1918 and took part in operations against the British during the War of Intervention in 1918-19. She was torpedoed in Kronstadt by British coastal motor boats (CMBs) on June 17. 1919.
The Kagul was renamed Pamyat Merkurya. in memory of the Merkurya, after the Russo-Japanese war. The Merkurya and the Kagul (ex-Ochakov) were active in the Black Sea during the First World War. and on January 4. 1915 Merkurya damaged the Turkish cruiser Hamidieh in a skirmish west of Sinope. In early May both ships patrolled off the Anatolian coast and the Pamyat Merkurya sank two ships at Kozlu. Between August and November they bombarded the Turkish coast at various points. In January 1917 the Pamyat Merkurya again raided the Anatolian coast in company with the battleship Ekaterina II and three pre-Dreadnoughts.
In 1905 the Ochakov’s crew joined the mutiny in the Black Sea Fleet and for a time she served as the rebels’ “flagship”. She was sunk in shallow water by gunfire from the loyal battleship Rostislav but was refloated and repaired. As a mark of the Tsar’s displeasure her name was removed from the record, and on April 7, 1907 she was renamed Kagul. On April 13. 1917. to commemorate her revolutionary fervour, and to wipe out the ‘stain’ of the censure, she was given back her old name, but was soon out of commission. She was recommissioned by the White Russians in February 1919 and renamed General Kornilov in September. In 1920 she was the last ship to leave the Crimea for Constantinople, but two months later she sailed for Bizerta. arriving there on December 29. 1920. The French government seized her as compensation for outstanding debts and she was scrapped in 1933.
During the First World War, as supplies of the new Vickers-designed 13-cm (5.1-in) gun became available, the class was rearmed. The Oleg and Bogatyr received 16 of the new guns, some of them replacing 75-mm (3-in) guns. The Black Sea ships were supplied with different guns; the Kagul received 12 13-cm guns in 1917, but her sister ship was merely given four more 15.2-cm (6-in) guns to replace some of the 75-mm guns on the broadside. The Baltic ships were given four 75-mm antiaircraft guns but the Black Sea ships had only two. The torpedo tubes were removed from the Oleg and Bogatyr. while the others were reduced to two beam underwater tubes.
After the Revolution the Pamyat Merkurya had a checkered career. While lying at Sevastopol in 1919 she was taken over by British forces, and when they withdrew in April they destroyed her machinery. The Red Army recaptured her in 1920. after the evacuation of Wrangel’s forces, and in 1923 renamed her Komintem. With rebuilt machinery and some alterations to her armament she recommissioned on May 1, 1923. but as her speed was now only 20 knots she was of little use except for training. It was later proposed to convert her to a seaplane carrier, but this was uneconomical even by Russian standards. In 1941-42 she took part in the defence of Odessa and Sevastopol. She was badly damaged by German air attack at Novorossisk on July 2. 1942 and limped to Poti, only to be hit again on July 16. A total loss, she became part of a breakwater in Poti harbour.
12 × 152 mm (6 in) guns (2 twin turrets and 8 single guns), replaced by 130 mm (5 in) guns in subsequent refits for all ships 12 × 11-pounder guns 8 × 47 mm guns 2 × 37 mm guns 2 × 15 in (380 mm) torpedo tubes
Deck: 80 mm (3.1 in) Turrets: 127 mm (5.0 in) Casemates: 80 mm (3.1 in) Conning tower: 140 mm (5.5 in)
Successive Royal Navy post-Dreadnought classes were basically improved versions of that pioneering warship. The next significant advance came with the Orions (Orion, Conqueror, Monarch, and Thunderer, constructed between 1909 and 1912). They were improvements over previous designs and were promptly called super dreadnoughts. Their new 13.5-inch guns gave considerably increased firepower for a small addition in weight and size; range was increased to a spectacular 24,000 yards. The Orions’ main batteries were arranged on a pattern pioneered by the U. S. Navy that would prevail until the last battleship was designed: All turrets were mounted on the centerline, and fore-and-aft turrets were superimposed one on the other, a vast improvement on the German and previous RN wing turrets. The Orions’ armor was extended up to the main deck, eliminating a major weakness of the early dreadnought classes. Still, they suffered from the same lack of beam, which gave inferior underwater protection compared to the German ships. The unsound British argument was that greater beam made the ship more unsteady and reduced speed. The Orions, as noted, were also the last RN dreadnoughts to position their firing platforms directly abaft the forward funnel.
The next major advances in battleship design were seen in the five impressive Queen Elizabeths (Queen Elizabeth, Valiant, Barham, Malaya, and Warspite, completed in 1915-1916). Well ahead of anything the German Navy would produce, they were confidently designed to outrace a retreating enemy fleet. The Queen Elizabeths were the world’s first large oil-burning warships. The Admiralty knew full well that the Germans would be unlikely to go over to oil-burning entirely, as the Germans, unlike the British, were presumed to lack an assured oil supply in wartime. (Of course, with their penchant for invading other countries, the Germans might have been expected to take over Romania’s oil fields, which is what they later did in World War I.) Also, oil gave considerably greater thermal efficiency, discharged much less smoke, and released all personnel from the filthy, time-consuming bondage of coaling. Oiling was simply a matter of running out hoses and opening valves. Thus Great Britain, with no domestic oil resources of its own, had given hostages to the world’s petroleum producers.
The Queen Elizabeths were also the first to mount 15-inch main battery guns, and all five units fired those guns at Jutland. They and two units of the following Revenge class (Revenge, Royal Oak, Ramillies, Resolution, and Royal Sovereign, completed 1916-1917) were the last RN battleship class to fight in World War I and, with the Elizabeths, were the only capital ships of any naval power to use their main guns against enemy battleships in both world wars. (Three more units, Renown, Repulse, and Resistance, were suspended, then canceled in 1914 at the outbreak of war.)
The dreadnought was easily the most expensive weapon of World War I. By contrast, the most costly war tool of World War II (1939-1945) was the U. S. Army Air Force’s B-29 Superfortress heavy bomber. Obviously, the battleship’s status had considerably depreciated since 1918; not one battleship was laid down and completed during World War II.
Yet paradoxically, there were considerably more battleship-to-battleship clashes in World War II than in World War I, although, as in World War I, there would be only one large fleet battleship action. Yet despite their diminished role in World War II, roughly the same number of battleships would be lost as in World War I (23 versus 25, including self-scuttlings).
Like the other naval powers, all battleship-oriented, the Royal Navy entered World War II with a collection of World War I-era battleships, modernized and unmodernized, and with new battleships on the way. It also had the only battleships in any navy designed and completed during the 1920s, Nelson and Rodney. Except for the Nelson class, the Royal Navy during World War II would lose one each from its other battleship classes, in all losing three battleships: Royal Oak, Prince of Wales, and Barham. The oldest of the Royal Navy’s battleships serving in World War II were the five Queen Elizabeths. Of them, Valiant, Warspite, and Queen Elizabeth had been given the most complete reconstructions of any RN battleship. The unmodernized Barham would be lost to submarine torpedo, taking 862 crewmembers, in 1941. Later came the five Royal Sovereigns, of which Royal Oak was lost in Scapa Flow, with 786 dead, in 1939, again to a German submarine torpedo. These later but cheaper warships were not as highly valued as the Queen Elizabeths, perhaps because they were slower and they did not undergo nearly as extensive a modernization. In fact, the Admiralty seriously considered expending two of this class as blockade ships off the German coast. One, Royal Sovereign, was loaned to the Red Fleet for the war’s duration.
The newest RN battleships of World War II were the King George V class (King George V, Prince of Wales, Duke of York, Anson, and Howe, not to be confused with the King George V class of 1911-1912). Again, one unit of this class, Prince of Wales, was lost during the war, this time to aerial attack by the Japanese in December 1941. The class was severely criticized for its 14-inch main guns. This retrograde decision (after all, the considerably older Nelson and Rodney boasted 16- inch guns) was made in order to get at least the first two units of the class completed in 1940, by which date conflict with Germany was expected. As it was, only King George V was ready for service in 1940. Like the Nelson class, the King George V class had significant maingun mounting problems. Nonetheless, the Royal Navy generally felt that the class gave good value for the money.
A follow-on class, the Lions, was designed to mount 16-inch guns, but the realities of World War II saw to it that these battleships did not get past the laying-down stage, if that. Even so, as late as 1943-1944, there was actually a brief flurry of interest in completing the Lions, which went nowhere. Two years into World War II, Great Britain laid down HMS Vanguard as a mount for the never-installed 15-inch guns of the freak giant battle cruisers Glorious and Courageous, long since converted to aircraft carriers. Vanguard was basically Winston Churchill’s idea (the prime minister always had a soft spot for battleships) and was supposed to reinforce the RN fleet at Singapore. But long before Vanguard was launched in 1944, the Singapore bastion had fallen ignominiously, and Prince of Wales (along with the battle cruiser Repulse) had been lost to Japanese airpower off Malaya. Work proceeded very slowly during the war on Vanguard, the largest and last British battleship ever built; it was not completed until 1946, never fired a shot in anger, and was scrapped in 1960.
The cancellation of the Lions and the slow pace of construction on Vanguard should not be taken as an indication that the Royal Navy had given up entirely on battleships. Incredibly, the First Sea Lord (i. e., the highest-ranking RN officer), Admiral Andrew Cunningham, in May 1944, well after Taranto, Pearl Harbor, and the loss of Prince of Wales and Repulse, argued that, for the postwar Royal Navy, “the basis of the strength of the fleet is in battleships and no scientific development is in sight which might render them obsolete” (quoted in Eliot A. Cohen, Supreme Command: Soldiers, Statesmen, and Leadership in Wartime, New York: The Free Press, 2002, pp. 121-122). Admiral Cunningham was no armchair theoretical navalist, but probably the best admiral the Royal Navy produced during World War II. Yet by the time Cunningham made his lamentable projection, the Royal Navy had ceased all battleship construction except for its leisurely work on Vanguard; after World War II it would lose no time in scrapping all its surviving battleships (except for Vanguard).
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REPORT ON EVENTS WHICH OCCURRED IN 14in TURRETS
23rd TO 25th MAY
Friday, 23rd May
A – Events prior to First Action
The order to load the cages was given late in the afternoon. In the course of loading the following defects developed:-
No. 2 gun loading cage: Front flashdoors could not be opened fully from the transverser compartment and the cage could not be loaded. Examination showed that the front casing had been badly burred by being struck by the lugs carrying the guide rollers on the gun loading rammer head when the latter was making a “withdrawing” stroke.
This was cleared by filing and the other gun loading cages were examined for the same defect. Slight burring was found in some cases and was dressed away.
No. 1 gun: On ramming shell the second time after the order “Load”, the shell arrestor at the shell ring level jammed out and could not be freed before the first action.
While steaming at high speed, large quantities of sea water entered “A” turret round the gun ports and through the joints of the gunhouse roof. It became necessary to rig canvas screens in the transverser space and bale the compartment.
No. 2 central ammunition hoist: Arrestor at shell ring level would not withdraw after ramming shell. It is impossible to strip this in place in the Mark II mounting, and the arrestor was removed complete. The axis pin of the pinion driving the inner tube of the arrestor had seized. There does not appear to be any effective means of lubricating this pin. The pin was drilled out and removed and the arrestor re-assembled. It was not, however, possible to replace the arrestor before action stations was ordered, because at this stage a defect developed in the hinge trays of the forward shell room as described below. This latter defect was taken in hand immediately in order to free the revolving shell ring and was completed a few minutes after action stations. It was not then considered advisable to proceed with replacing the arrestor.
Hinge trays at forward shell room fouled the locking bolt on the revolving shell ring: both trays being bent.
Saturday, 24th May
During the early hours hydraulic pressure failed on the revolving shell ring ship control in “B” turret. This was due to the pressure supply to the turret from the starboard side of the ring main being isolated. The revolving shell ring ship control is fed from the starboard side only, and the non-return valves on the pressure main adjacent to the centre pivot prevent pressure being fed to the starboard side and the revolving shell ring ship control from the port side in the event of the former being isolated from the ring main. Similar conditions exist on the port side of “A” and the starboard side of “Y”. It is considered essential that a cross connection be fitted in the shell handling room with two non-return valves so that the revolving shell ring ship control can be supplied from either side of the ring main.
B – Events during the First Action
The following defects developed in “A” turret:-
On several occasions the shell ring rammers fouled the brackets on the hinge trays for No. 11 interlock. Shell could not be rammed until the bearing of the turret was changed. This also occurred in “Y” but did not prevent ramming.
No. 1 gun only fired one salvo, due to the events described in A (i).
After the second salvo, No. 24A interlock failed on No. 2 shell ring rammer. It was tripped after a short delay and thereafter assisted by hand.
About halfway through the firing, the tappets operating the shell ring arrestor release gear on No. 4 rammer failed to release the arrestor. Subsequent examination has shown that the shaft carrying the levers operating these tappets had twisted. The rammer was kept in action by giving the tappets a heavy blow at each stroke.
Shortly after this, a further defect occurred on No. 4 shell room rammer. When fully withdrawn the rammer failed to clear No. 7 interlock and the ring could not be locked. This was overcome by operating the gear with a pinch-bar at every stroke.
Throughout the engagement the conditions in “A” shell handling room were very bad; water was pouring down from the upper part of the mounting. Only one drain is fitted and became choked; with the result that water accumulated and washed from side to side as the ship rolled. The streams above and floods below drenched the machinery and caused discomfort to the personnel. More drains should be fitted in the shell handling room and consideration given to a system of water catchment combined with improved drainage in the upper parts of the revolving structure. Every effort is being made to improve the pressure systems and further attempts will be made as soon as opportunity occurs to improve the mantlet weathering, but a certain amount of leaking is inevitable.
No mechanical defects.
The following defects occurred in “Y” turret:-
Salvo 11 – No. 3 central ammunition hoist was raised with shell but no cordite; No. 25 interlock having failed to prevent this. The interlock was functioning correctly before the engagement. There has been no opportunity to investigate this. It is also reported that the reason no cordite had been rammed was that the indicator in the cordite handling room did not show that the cage had been raised after the previous ramming stroke. This caused the gun to miss salvoes 15 to 20.
Salvo 12 – Front flashdoors of No. 2 gun loading cage failed to open and cage could not be loaded. Flashdoors on transfer tubes were working correctly and investigation showed that adjustment was required on the vertical rod operating the palm levers which open the gun loading cage doors. To make this adjustment, three-quarter inch thread had to be cut on the rod. This defect was put in hand after the engagement had been broken off and was completed by 1300. It would appear that the operating gear had been strained, possibly by the foreign matter in the flashdoor casing making the doors tight. The doors were free when tried in the course of making the repair. This caused the gun to miss salvo 14 onwards.
Salvo 20 – Owing to the motion of the ship, a shell slid out of the port shell room and fouled the revolving shell ring while the latter was locked to the trunk and the turret was training. The hinge tray was severely buckled, putting the revolving shell ring out of action. The tray was removed, but on testing the ring it was found that No. 3 and 4 hinge trays of the starboard shell room had also been buckled and were fouling the ring. The cause of this is not yet known. The trays were removed and as the action had stopped by this time, No. 4 tray was dressed up and replaced. The ring was out of action until 0825.
C – Events subsequent to First Action
During the day in “A” turret, No. 1 central ammunition hoist shell arrestor was driven back with the intention of carrying on without it by ramming cautiously. The gun and cages were then loaded, but owing to the motion of the ship the round in the central ammunition hoist cage slid forward until its nose entered the arrestor, putting the hoist out of action again. Subsequent examination has shown that the anti-surging gear in this cage was stiff and consequently did not re-assert itself after ramming to traverser.
D – Events during the Second Action
No. 1 gun fired only two salvoes owing to central ammunition hoist being out of action as described above in C, para 1. At salvo 9, No. 3 central ammunition hoist shell arrestor jammed out.
“B” and “Y” Turret
E – Events subsequent to Second Action
No. 3 central ammunition hoist shell arrestor was removed complete from the hoist. Time did not allow of it being stripped and made good, but it was intended to use the hoist without it. The gun and cages were loaded in this manner.
F – Third Action
First Salvo – Shell rammed short into No. 3 central ammunition hoist cage. In trying to remedy this a double ram was made, putting the shell ring out of action. The second shell was hauled back by tackle, clearing the ring. The base of the shell in the central ammunition hoist cage was jamming against the upper edge of the opening in the hoist. This could not be cleared as the central ammunition hoist control lever cold not be put to lower. After much stripping the trouble was located in a link in the control gear which was found to be out of line.
G – General
With pressure being kept on shell room machinery for a long period, much water has accumulated in the shell rooms and bins. Suctions are fitted from 350-tomnm pumps only and these are not satisfactory for dealing with relatively small quantities of water. Drains are urgently required. It is suggested that a drain be fitted at each end of each shell room and larger drain holes be made in the bins; present drain holes being quite inadequate and easily choked.
The drains should be led to the inner bottom under the cordite handling room. Non-return valves and flash-seals could be fitted if considered necessary.
On passage to Rosyth after the action, two further hinge trays in “Y” shell handling room were buckled by fouling the revolving shell ring.