French Navy Fire Control WWII

The French battleship Richelieu shows her fire controls at Portsmouth in August 1946. She was designed to be armed with a 381mm (15in) main battery and with dual-purpose 152mm (6in) guns. The 152mm (6in) director sits atop the 381mm (15in) one. Richelieu had 14m (46ft) rangefinders (triplex in the forward director, duplex in the turrets, with an 8m/26.2ft duplex unit in the after main battery director). The rangefinder in the director had a stereo element to detect changes of course by the target. As in the previous class, the main-battery director was surmounted by two for the secondary battery, the upper one being for anti-aircraft fire. It was never completed, and it was removed when the ship was refitted in the United States in 1943. The forward main-battery director showed four rather than three windows (with armoured hatches on either side). It had a shorter rangefinder forward of the main director (about mid-length), presumably a spotting glass (this rangefinder is not listed in a book describing the ship, but it is quite visible in a photograph). Similar secondary rangefinders or spotting glasses are evident in the sides of the two secondary-battery directors stacked atop the main-battery director. The secondary rangefinders were apparently removed when the ship was refitted in the United States in 1943 (at the same time the uppermost of the two secondary-battery directors was removed). The director visible alongside the superstructure served the ship’s 100mm (3.9in) anti-aircraft guns. The 152mm (6in) directors visible atop the forward superstructure each carried an 8m (26.2ft) duplex stereo rangefinder, but the after 152mm (6in) director visible carried a 6m (19.7ft) instrument. The secondary turrets and director used single 8m (26.2ft) rangefinders (note the narrower tube). Atop the bridge was a 3m (9.8ft) stereo navigational rangefinder. Just abaft it was a 4m (13ft) stereo rangefinder for the ship’s 100mm (3.9in) tertiary battery, added during construction because the 152mm (6in) guns were insufficient for long-range anti-aircraft fire. The ship was modernised with a mixture of British and US radars, such as the British Type 285 on the secondary director and Type 284 on the main-battery director, the British Type 281B air-search antenna at the foretop, and the US SA-2 radar on the mainmast, SF (surface-search) in the small radome forward, and SG surface-search set on the foremast. Richelieu’s sister ship Jean Bart was completed postwar with a completely different main-battery director similar in shape to a British DCT, carrying a main-battery radar (ABM) on its flat face, with a 14m (46ft) triplex stereo rangefinder. Above the radar were four windows like those of the earlier Richelieu director.

Le Prieur’s combinateur was superseded by a range-keeper produced by the Direction d’Artillerie Navale de Toulon. It became the basis of further development. For the first time in France it separated own and target calculation, using two separate plateaus, each driving its own tachymeters for motion along and across. A feature used again in later systems was to indicate the trial solution by two wires: horizontal and vertical for speeds along and across. A diagonal wire indicated trial inclination. Apparently this was independent of the British work on the AFCT. The method of evaluating a trial solution did not resemble the cross-cut concept in American and British systems. In the 1922 production version the table required a supervisor and three operators (for target, shooter and wind). Although this range-keeper was successful, only eight were made (two by the Direction d’Artillerie Navale in Toulon and six by Breguet in Paris).

Working with the range-keeper were range and bearing plotters. They were the vital means of feedback, and the French also considered them essential to a ship firing at a target that might be visible only intermittently. Readings from the four main rangefinders (masthead and triplex) were averaged mechanically. Simpler receivers showed ranges from the five or seven turret rangefinders and estimates by the fire-control officer. Corrections by the gunnery officer were taken by telephone and entered manually. To allow for limited plotting-paper width, the range plot was periodically recentred.

The first full system, for PC Model 1922, was operated by eighteen men with an officer and a petty officer (chef de poste) supervising them. As in the 1917 version, it separated the target motion (range and deflection) and ballistic elements of the problem, with the target motion in the centre. As before, the supervising officer stood at the graphic plotter for range. He had his aide next to him. To his right (at right angles) was the pair of plateaus (target and own-ship) combined in one casing, each with its own operator. Next to that was the bearing plotter (IVL, indicateur de vitesse laterale), with its operator. Behind it was the deflection operator, with two tachymeter operators and the gyro-compass receiver. As in the earlier system, the ballistic corrections and wind corrections were inserted to one side, in this case behind the plateaus. Spotting corrections and transmission to the guns were all concentrated on the other side of the space, each with its own operator. Errors were registered in both range and bearing (ecartes orientées). Many of the panels and devices needed operators to follow up their indications in order to insert these numbers back into other calculators; the entire PC was hardly integrated as desired. However, its personnel included an electrician, to keep it running, a technician (the derouleur) to keep the plotters running, and a talker at a bank of telephones.

The core of this system was the new separatedelement plateau. It was tested on board the cruiser Pothuau and then installed on board the modernised 23,000-ton battleships. A plateau with the associated integrator (tachymeter) Model 1920–23 was installed for the battleship secondary batteries and on board the new 8000-ton light cruisers.

The first integrated system, the prototype for the later ones, was developed beginning in September 1925 for the new Duquesne-class heavy cruisers. Work required about 6000 man-days; it was completed in 1927. Design was complex partly because some elements had to reverse their positions up to twice a second, yet positions had to be shown precisely. Data were carried internally mainly by rods, and, to avoid inaccuracies as they twisted, it used 600 roller bearings – and 300 gear wheels in differentials to add data. Minimum complement was eight, but normally the PC required two officers and eighteen enlisted personnel. If the tachymeters were not working another six men were needed.

The new design reflected the modernisation of French industry, which was moving towards standardised parts and precision measurements, particularly using standards promoted from 1925 by the Bureau de Normalisation de l’Automobile (BNA). It exploited new American machinery for precision gear-cutting and also newly improved ball bearings. More parts were interchangeable or suited for mass production. Existing commercial synchronous motors no longer seemed precise enough.

The calculating part of the system was progressively simplified, so that in 1930 the new cruiser or destroyer range-keeper required only two operators. It incorporated a parallax corrector and a single dial to enter temperature and pressure corrections. Corrections for drift and for the movement of the firing ship were now automatic. In 1937 a French artillery officer assured students at the French naval war college that the target element of the fire-control systems on board the heavy cruisers were adapted to take target turns into account.

The new cruisers were expected to fight fast, violently manoeuvering targets at ranges as great as thirty kilometres (eighteen and a half miles) (the designers worked to forty kilometres, which meant 100-second time of flight). Maximum target speed was forty knots (twenty metres [twenty-two yards]/second). That was not all: experience had already shown that a heavy cruiser could change course about two degrees per second. The system was therefore designed to take data from an inclinometer, rather than to rely on a deduced constant target inclination.

High-speed combat required that data be input instantly and that results appear instantly. Delays inherent in manual data entry could not be tolerated: even if one turn of a handle represented 500 metres (547 yards), the delay involved in turning it would be noticeable. Past calculators had generated future target position, but in this system it was displayed on a third dial so that future target bearing could be compared directly with present bearing. That did not require any new integrators, but the presentation was unique to the French navy. As in other synthetic systems with separated elements, this one used four integrators (tachymeters): two for range rate (own and target) and two for speed across (own and target). Design was greatly simplified by reducing all range corrections to changes in time of flight; range outputs were reduced to gun elevation and time of flight. A fourth dial showed wind speed and direction, because the longer ranges now desired entailed more wind effect, both because they acted longer on the shell and because the shell attained higher altitudes, where wind was stronger.

As before, the future-target dial showed horizontal and vertical wires for trial speeds along and across the line of fire. The third wire, however, was set by inclinometer (or other observation). The three wires formed a triangle, the chosen solution being its centre. A further innovation making for faster computation was a calculator that could indicate how a result could change if the inputs changed slightly, rather than require resetting.

Associated plotters (for feedback) gave range and bearing.

The first of the new battleship fire-control systems, for the Dunkerque class, was a modified heavy-cruiser system, although it was associated with entirely new directors. Like the cruiser, the battleship required twenty-six personnel in her PC; she also had a four-man computer in each main-battery turret, and three nine-man anti-aircraft control posts for her dual-purpose 130mm (5.2in) guns.

The last pre-war cruisers, the La Galissionière class (7600 tonners) had a new kind of PC designed specifically for dual-purpose fire, although they had single-purpose 155mm (6.1in) guns. (The Richelieu class had the same guns in triple dual-purpose mounts, which may also have been intended for the cruisers). The concept was to transfer the usual salvo firing from surface to air targets, using time-fused projectiles. To do that, calculations had to be completed much faster, the guns ready for instant action. Because anti-aircraft shells were much lighter than anti-ship shells, they entailed different ballistics and corrections were more critical. To accommodate its extra functions, the PC had to be larger than that of a heavy cruiser. The kinetic section was U-shaped, with a desk carrying the plateaus and the target-estimation cross-wires on one arm and the azimuth plotter on the other. The two arms were connected by a long arm carrying range and altitude plotters, with a parallax-inverter between them (parallax was particularly important). Behind this arm was the big block of tachymeters. To the usual pairs of tachymeters for range (own and target) and bearing was added a fifth, for range against an air target. The additional range calculator was needed because range rates against floating targets might be up to twenty metres (twenty-two yards)/second, but against an air target 160 metres (175 yards)/second had to be allowed for (about 315 knots). The usual separated plateau calculators were abandoned in favour of more compact ones easier to integrate into one unit. Because the inclination of the target in the firing plane might change while the shell was in the air, the opportunity was taken to split the target plateau into a plateau for current target inclination and one for future target inclination. In the case of an air target, the second plateau was used for wind at the target. Because it had to be used for air as well as for surface targets, the target plateau (current) had to have two speed scales.

Overall, the difficult requirements imposed by the dual-purpose PC pushed French designers towards greater automation, generally using electrical methods. This included a better method of averaging ranges for plotting. This technique in turn was applied to many existing 1929M plotters at the end of 1936 (as conjugateur 1929M36), the rangefinder data automatically being turned into an average curve rather than the usual series of dots, which had to be traced by eye.

The new PC required twenty-eight personnel, but only four or five of them needed much training (ie, would be required to exercise judgement); the others operated follow-ups or performed other, essentially mechanical tasks. Compared to a heavy-cruiser PC, this one used the same ‘forest’ of rods, but hid them away.

The new generation of fire-control systems changed French naval tactics. The French were very much aware that they were gaining freedom to manoeuvre while firing, to the extent that a 1937 lecturer at their naval war college commented that with such freedom much of the difference between armoured and unarmoured ships was disappearing. Manoeuvre as protection against fire became a theme in lectures at the war college, even though, as the French freely admitted, they knew little of enemies’ fire-control systems. The time scale for manoeuvre depended on the dead time between firing and making spotting corrections, which might be as little as fifteen seconds once the enemy had the range (the idea of changing speed was dismissed because the dead time involved was at least a minute). The idea of manoeuvre as protection against fire also affected ship design. The 1937 lecturer argued that the new Dunkerque- and Richelieu-class battleships were unusually well adapted to such tactics because by concentrating their armament in two superimposed turrets forward they gained unusually wide arcs within which to manoeuvre while firing.

The Mediterranean Fleet battleships conducted their first experiments in long-range firing in 1926, ships opening at extreme range (in one case at 22,000 metres/24,060 yards, in others between 16,000 and 20,000 metres/17,500 and 21,872 yards). Such ranges were far short of the theoretical maximum, but they were set by the limits of the guns and, for ships without directors, by the limited visibility from the turrets (maximum 16,000 metres/17,500 yards). Another surprise was that long range made for a slow fire-control tempo (ie, the entire fire-control cycle) because of the long time of flight. Typical reloading time was forty-seven seconds, and spotting time was fifteen seconds. Thus if time of flight (plus fifteen seconds) was less than reloading time, the ship had to be able to fire salvoes faster than she could reload, so half-salvoes were the rule. However, at a range of 22,000 metres (24,060 yards) time of flight was forty-seven seconds, so the guns had to await spotting to fire. The crossover came at 15,000 metres (thirty-two-second time of flight). This was the logic of the British ladder technique, apparently unknown as yet in the French navy, despite the presence of French officers in the Grand Fleet. At this time the French apparently assumed that they would need four salvoes to begin to hit, which at 22,000 metres (24,060 yards) (interval sixty-one seconds) meant four minutes four seconds. Overall, the rate of fire might fall to a third of that at shorter range, say from eighty to twenty-six shots in ten minutes. Yet speed would be increasingly important in combat. Earlier practice was to expend initial salvoes to correct for line, before correcting for range. With so few salvoes available, that meant wasting too much time. It might be possible to avoid the initial salvoes altogether. In seventeen runs ships usually got line correct on their second or third salvo (three on the first, eight on the second, six on the third). Perhaps salvoes could be fired for line and range. The fleet also found that its dispersion was increasing, in some ships doubling to 600 metres (656 yards) in three years. Director control did not seem to affect performance.

The fleet also tried two concentration shoots (three ships each time), one using centralised control, one using a mixed system of autonomous and paired control. In centralised control, coordinated by short-wave (HF) radio, the first salvoes of the ships (three, three and five rounds) included nine rounds falling within 175 metres (191 yards), and four on target, all within about forty seconds. Firing autonomously, the three ships got seven rounds on target during the first two minutes and thirty seconds of fire.

Despite considerable talk about future ranges of 40,000 metres (43,744 yards), and the design of guns capable of firing to ranges as great as 35,000 metres (38,276 yards) (in response to the French commission on naval lessons of World War I), as late as March 1934 a student thesis accepted by the French naval war college began with the statement that almost nothing had been done to push range beyond 18,000 metres (19,685 yards). Only very recently had tests been conducted with the cruiser Colbert.39 However, shells were redesigned for greater range, the last pre-World War II generation being boattailed with long windshields (approaching half the length of the shell). Maximum range of the 381mm (15in) gun (thirty-five-degree elevation) was 41,700 metres (45,600 yards), compared to 42,260 metres (46,216 yards) for the Italian 15in/50 and 35,550 metres (38,877 yards) (at thirty degrees) for the German 381mm/15in/48.4.40 The last ships to fire extensively pre-war were the Dunkerque-class light battleships; on at least one occasion Dunkerque fired to a range of 41,000 metres.

As late as 1936, the US naval attaché reported that the French preferred to use director fire in train and pointer fire in elevation. Typically salvo bells allowed a six-second interval, during which pointers could fire if their sights were ‘on’. These comments presumably applied to old battleships rebuilt before modern director systems had entered service. In these ships the director was inside the conning tower. In cruisers, however, it was combined with a rangefinder at the masthead, and in destroyers the director was a large structure above the bridge. Ships fired ladders (echelons) with a 183-metre (200-yard) step, typically comprising three steps above rangefinder range (plus a ballistic correction). US observers considered French use of aircraft for spotting undeveloped by their standards. However, they did note that the French conducted offset firing for realism (they thought an air spotter would find it almost impossible to correct fire under such circumstances). Dispersion between turret guns was small, a figure of fifty metres (fifty-five yards) at 28,000 metres (30,621 yards) (presumably for a heavy cruiser) being quoted. Delay coils were introduced in 1941 to reduce salvo spreads.

Pre-war interest in concentration fire was revived. As modernised, the Bretagnes could fire beyond the horizon; three of them firing together could deliver twenty-six tons of shells on target. The French therefore became interested in master-gun tactics, the ship closest to the target (the director) carrying the observer. Ranges would be transmitted by radio every two seconds, alternating with target bearing. All ships would fire together on order, each interpreting the data sent by the directing ship, and using her own computer to work out range and range rate. Each ship would keep track of the position of the directing ship. To this end each of the Bretagnes and Courbets was fitted with a separate central de telecommande forward of the PC for her main battery. Her foremast carried a 2m-(6.5ft-) diameter range dial (marked in hm increments, 0 through 9); a second range dial was on her mainmast. Concentration dials also appeared on board other French warships, down to destroyer size.

Concentration was particularly important for the super-destroyers (contre-torpilleurs), organised in divisions of three; the French hoped that a division could overwhelm a light cruiser. Beginning with the Fantasque class, they had special HF radio circuits to pass range, target course and speed, deflection, and spots (using dedicated antennas strung from the foremast to B gun platform). A separate higher-frequency circuit was provided for a bridge-to-bridge radio telephone, for tactical control of the division. Master ship concentration (directed by the division leader) required that each ship know not only the range to the target but also the range and bearing of other ships from which target data could be taken (to determine parallax). To this end they had pairs of 0.8m (2.6ft) coincidence rangefinders, one for each possible engaged side (they were replaced in 1939 by 1m (3.2ft) stereo units, which could also be used for antiaircraft control).

In the summer of 1936 the French navy began widespread use of K shells, which had coloured dyes to distinguish splashes from different ships firing together. This technique so impressed the Royal Navy that it adopted the French shells in modified form during World War II.

Although the French navy had little chance to demonstrate long-range gunnery during World War II, it did show impressive capabilities in its few battles against the Royal Navy. At Dakar in September 1940 the super-destroyer Le Fantasque claimed hits at 20,600 metres (22,528 yards) (using the ship’s roll to extend the usual maximum range of 20,000 metres/21,872 yards). The cruiser Georges Leygues claimed two hits on the battleship HMS Barham at 16,000 metres (17,500 yards) and she and Montcalm duelled British heavy cruisers at ranges between 24,000 and 27,000 metres (26,250 to 29,530 yards) (the French cruisers were straddled constantly but not hit).


Corsairing [English] Operations in the Mediterranean


In addition to traditional corsairing operations in the Mediterranean, several new ones were sponsored in the late sixteenth and the early seventeenth century by Christian states such as Spain, Tuscany, Sicily and Monaco. These states also licensed additional vessels to sail as temporary corsairs under their protection, usually as wartime auxiliaries, but sometimes independently. Among the permanent new enclaves, two were developed as the great period of the sixteenth-century war wound down. In northwest Italy the Grand Dukes of Tuscany operated a fleet against the Muslims in the sixteenth century, but they gave it up in 1574 and sold some of their galleys to the Knights of St Stephen, a crusading order founded by Cosimo II di Medici (1537–74). Though these knights never had the discipline or the prestige of the Knights of Malta, with whom they sometimes collaborated, they styled themselves Christian crusaders and were authorized ‘to seize the ships and goods of any states which were not Roman Catholic’. With their base in Livorno (known as Leghorn to the English), they launched their first assault on Muslim trade and ports in 1564. The sales of booty in Livorno enriched the city and its ducal patrons, just as similar sales enriched the Knights of Malta and the beys of Barbary. Merchants and corsairs from northern Europe, especially England and Holland, streamed into Livorno in the late sixteenth century, swelling the population to about 5,000 by 1601.

Nearby Savoy had an official galley fleet that sailed against Muslim shipping. In addition, for a share of the loot, the Dukes of Savoy licensed pirates who settled in Villefranche. The port was very active in the early seventeenth century, because Spain had resumed attacks on the corsairing ports of Barbary and Morocco. With the activities of the Barbary corsairs restricted, the Christian pirates of Livorno and Villefranche sailed in to fill a niche in the market for stolen goods. Like Livorno, Villefranche attracted an international mix of adventurers, including many English pirates and merchants, who made enormous profits from the seizure and sale of booty. Marseilles was another favored port for northerners, where the notorious pirate Danziker held a commission from King Henry IV of France.

Sizeable numbers of English pirates settled in North Africa as well as Italy after 1604, when an Anglo-Spanish peace treaty put privateers out of work. In response, they simply changed venue and continued preying on Spanish shipping. English pirates had few ships in the Mediterranean at that point, but they were able to seize prizes with swift and heavily armed sailing ships. Once established in Barbary, English pirates could easily find ships and crews for corsairing expeditions. Northern European pirates tended to sail from fall to spring, Barbary pirates favored the summer; combined, they presented a year-round scourge to the shipping of Venice and Spain, in particular. In the summer of 1608 alone Algerian pirates captured 50 vessels off the Valencian coast. The reintroduction of the armed sailing ship to the Mediterranean was one of the most lasting developments of the seventeenth century. After a century of development in the Atlantic and beyond, the most agile of these vessels were well suited to Mediterranean piracy and cheaper to operate. The Grand Dukes of Tuscany bought sailing ships in 1602, and there are reports of numerous raids by sailing ships in the eastern Mediterranean in the early seventeenth century. Galleys were still in use, of course, but they faced increasing problems of maneuverability as artillery became heavier.

French Navy in America

The French fleet of 1757 as depicted by Captain Pierre Bouchard de la Broquerie. The ships are (from left to right) La Marquise de Vaudreuil, La Hurault, La Louise and Le Victor.

In 1685, La Barre, Frontenac’s successor, had a barque built at Cataraqui, which was named Le General Little is known of her, other than she plied Lake Ontario for several years and made three trips to Niagara in 1688. There is some doubt as to whether Le General was a new vessel or one of La Salle’s four earlier ships that had been rebuilt. Later, a fleet of flat-bottomed transports were added. Although these were hardly sailing ships, they did carry four-cornered lugsails. In 1687, the French launched a major attack against the Iroquois using the ships already mentioned and 198 such transports.

The French abandoned Fort Frontenac in 1688, and burned two of their ships at that time to prevent others from using them. No record has been found of what happened to the third, though in 1694, when the French re-occupied the fort, they raised one vessel from the harbour bottom, rebuilt her and put her into service.

The next shipbuilding, of which any record exists, was in 1726 when two schooners were built at Fort Frontenac by Intendant Begin. In 1743 and 1745, Chevalier de Chalet added two more, the St. Charles and the St. Frangois. Both were about 50 tons burthen. In 1734, Louis Denis, Sieur de la Ronde was sent by the governor of New France, to explore and report on the copper deposits at Chequamegon in 1727. He built a barque at Point aux Pins on Lake Superior for the copper mines at Chaguamagon, now part of Wisconsin. She was the second sailing vessel on the Upper Lakes and the first vessel to be described as sloop-rigged. It is not known what happened to her. The next mention of sail on Lake Superior concerns the English trader, Alexander Henry, in 1770. He could possibly have been using the same vessel, though this is unlikely.

About this time the “goelette” (an early version of the schooner) and the schooner started to come into use on the lakes but there are not sufficient records of early ships to indicate the exact date of their arrival.

Several vessels were built at Cataraqui (now known as Kingston, Ontario) in the period from 1743 to 1756:

Le Victor: 1749, 40-ton, schooner rig but later changed to sloop, 4 guns.

La Louise (or Lionne): 1750, 50-ton schooner, 6 guns.

La Hurault: 1755, 90-ton schooner, 14 guns.

La Marquise de Vaudreuil: 1756, 120-ton schooner, 20 guns.

Three lateen-rigged gunboats, names unknown, and two schooners, one large and one small, were built at Niagara but were not launched before they were captured by the British in July 1759. Records indicate that four vessels were built by the French at Navy Island, but it has not been possible to discover their names nor what happened to them.

New German Submarine Production

In the fall of 1943, Dönitz ordered 152 Type XXI and 140 Type XXIII sub marines. Speer examined the plans and he promised the first Type XXI would be ready in April 1944. Speer determined that the need for early availability of the submarines ruled out the luxury of making a prototype. This later resulted in a number of problems. Speer had established a Central Board for Ship Construction with representatives from both the navy and the Armaments Ministry. He selected Otto Merker (1899–1986), a man from the automobile industry to head the board. To reduce the construction time, Merker proposed a modular approach. Naval engineers estimated that this would reduce construction time from about 22 months to 5–9 months. It would also halve the time submarines were in slips, greatly reducing the time they would be vulnerable to Allied bombing. Merker’s decision on modular construction may have been influenced by the American building of Liberty Ships.

A great number of industrial sites were involved in this mammoth project. Each hull consisted of eight prefabricated sections with final assembly at the shipyards. Some of these sections weighed as much as 150 tons and were too heavy for the rail system. Consequently, they were shipped via rivers and canals to the final assembly yards in Danzig, Bremen, and Hamburg. The Germans planned eventually to transfer all assembly operations to a gigantic bomb-hardened assembly plant at the Valentin submarine pens in the small port of Farge downriver from Bremen. Work on this enormous facility began in early 1943. The plant was nearly complete in March 1945 when it was severely damaged in an Allied air raid using bunker-buster bombs. It was still not completed when the war ended.

Although Dönitz had expected 152 XXIs and 140 XXIIIs to be completed by the end of October 1944, the completion schedule could not be followed for a variety of reasons as detailed below. Only 118 Type XXI were completed by the end of the war and only four of these were ready for combat. Only 59 Type XXIIIs of the 140 planned for were ready by the end of the war and only six put to sea, the first on 29 January 1945 and the last on 4 May. None was sunk while engaged in operations.

Production Obstacles

There are those who claim that the new boats should have been given a higher priority in armament production. They forget the fact that Hitler was caught in a “Catch 22” situation. If he reduced the priority accorded the Luftwaffe, the facilities needed for submarine construction and the synthetic oil refineries would have been destroyed earlier than was the case. If he reduced the priority for the army, replacements for the hard-pressed units in both the East and West would quickly slow down, as would equipment for the new divisions that were being formed. Lowering the priorities for the other two services could only lead to undesirable situations and a shortening of the war. Professor Grier provides some interesting and telling figures in this regard. He notes that the steel required for the Type XXI submarines “would have provided Guderian 5,100 additional tanks” and that another ‘miracle weapon’ program, the V-2 rockets “devoured resources equivalent to 24,000 combat aircraft.” He concludes that “the German war effort certainly would have benefited more from five thousand tanks than from Dönitz’ ‘miracle weapon.’”

A possible solution to the problem was to withdraw units that were ordered to defend the “fortified places” to shorter defensive lines. The wisdom of some decisions can only be judged retrospectively. This was not the case with allowing large forces to be voluntarily encircled or besieged without realistic prospects for relief or re-supply. History tells us that this is a virtually certain prescription for disaster. The new submarine program, on the other hand, cannot be judged realistically except in retrospect.

The lack of prototypes for the new submarines and the fact that many companies involved in the modular construction had little experience in shipbuilding caused severe problems. Much time was wasted because the modular sections did not interlock properly because specific tolerances were exceeded. Additional delays were caused by the long training time required for crews. Most sources note that the normal submarine training time was about three months, but the new types, because of their advanced technology and design complexity, required around six months. The Allies had also started—on August 7, 1944—heavy aerial mining of the Bay of Danzig, now the primary German training area. The mining forced the Germans to move their training to the less suitable Bay of Lübeck. A number of new submarines that were near the completion of trials and ready to head to Norway for stationing were lost in the Bay of Lübeck, probably victims of mines. The loss statistics of Claes-Göran Wetterholm undoubtedly include those lost in routine training accidents.

Allied bombing of production and assembly facilities became an increasing problem for German submarine output. Except for the mining operations in the Baltic, the Allies did not make a concerted effort to damage and destroy the German submarine facilities until January 1945. This objective was simply not on the priority list of the strategic air offensive. Instead, the priorities of the Allied heavy bomber forces were:

  • Synthetic oil facilities
  • Transportation network
  • Tank and mechanized transport production facilities.

The British Admiralty was aware, however, that the Germans were developing new submarines. Intelligence was collected not only through an analysis of Enigma deciphers but by reconnaissance flights over German harbors. By mid-December the National Intelligence Division had come up with a rather accurate estimate and status of the new German submarine production. They estimated that 95 Type XXIs were under construction or in various stages of preparation and that 35 had already been commissioned. The Enigma deciphering even allowed the British to conclude that the commanders appointed to skipper these submarines were experienced and capable.

From their information on the German submarine program, the Allies were less worried about the existing submarines being fitted with snorkel and the Type XXIII than they were about the ocean-going Type XXI. The Allies felt that they could handle the threat from the snorkel and Type XXIII submarines by using existing anti-submarine warfare assets to the maximum. However, they felt that the Type XXI could seriously impede transport across the Atlantic and threaten landing operations if those submarines were deployed in sufficient numbers. Only a dramatic increase in anti-submarine warfare assets could counter this possibility. The alarming intelligence reports caused the Admiralty to urge a heavy bombing campaign against submarine production facilities and slips.

The Royal Air Force, which was somewhat skeptical about the navy’s intelligence, concluded that an aerial campaign of the kind that was suggested by the Admiralty had to be on such a large scale that it would constitute a serious detraction from existing priorities. They noted that German armored forces and the Luftwaffe were seriously constrained by lack of fuel and that any relaxation on existing priorities would lead to the resurgence of the Luftwaffe and allow the Germans to increase their operations vastly on all fronts. The German coal and oil supplies had, by January 1945, been cut to a fraction of what was needed to prosecute the war on two fronts. Therefore, they argued, there should be no shift in priorities until it was shown that the naval commands could no longer cope with the threat.

In the end, the Admiralty convinced the Combined Chiefs of Staff in mid-December 1944 that it was necessary to take the requested action as long as it did not imperil existing priorities. Heavy Allied bombers were ordered to carry out secondary strikes against submarine facilities. Below is a listing of major raids carried out against the submarine facilities and a summary of their results:

  • 18/19 December 1944—a “target of opportunity” raid by 227 Lancaster bombers dropped 817 tons of bombs on Gdynia, a port on the west side of Danzig Bay. The bombs sunk two submarine depot ships, a torpedo boat, and five merchant ships. An oil refinery ship, the World War I battleship Schleswig Holstein, and a Type XXI—about to undertake the final training exercise in the Gulf of Danzig—were heavily damaged.
  • The first attack by the US Eighth Air Force was carried out on December 31, 1944, when 324 bombers attacked Hamburg, dropping 740 tons of bombs. The Germans shot down 24 aircraft. The raid resulted in the destruction of four Type XXI submarines while seriously damaging two others. A large depot ship and several other vessels were also destroyed.
  • An attack on the canals through which pre-fabricated sections were brought to the assembly yards was carried out on January 1, 1945, resulting in the Dortmund–Ems and Mittelland Canals being put out of service until February 6.
  • A very successful raid was carried out by the Eighth Air Force against the submarine assembly yard at Hamburg on January 17. The results of the 360 tons of bombs dropped were impressive. Three commissioned Type XXI were destroyed and nine others were seriously damaged. Five merchant ships were also sunk and three damaged. The US lost three aircraft.
  • Precision bombing by small groups of Mosquitoes, each carrying a 4,000lb bomb, was carried out against a Type XXI yard in Bremen. These attacks were carried out nightly from February 17 until the end of the month. The most successful attack was carried out on February 21/22. Two Type XXIs were damaged and the launch of three others blocked by debris.
  • Eighth Air Force carried out a 198-aircraft raid on the yards at Bremen on February 24. While only one Type XXI was sunk, two floating cranes and the crane used for preparing the submarine were badly damaged.
  • An unusually heavy attack by 407 bombers of the Eighth Air Force was carried out on March 11 against the Bremen yard. This attack was so damaging that it virtually shut down the yard.
  • A damaging raid on the canal system in February again made it unusable. Another raid on the canal system on March 3-4 damaged it beyond repair.
  • Three devastating raids were carried out against the facilities in Hamburg—two by the Royal Air Force and three by the Eighth Air Force. The facilities were virtually brought to a standstill. Eleven older submarines were sunk and five Type XXI were dam aged beyond repair. A new destroyer and 15 other ships were also sunk.
  • Two destructive attacks were carried out in late March on the gigantic submarine pen at Farge, near Bremen. One raid was carried out by the Royal Air Force while the other was delivered by the Eighth Air Force. The damage delayed construction.
  • Heavy raids were carried out by the Eighth Air Force in April 1945 on the port facilities at Kiel. A total of 1,184 aircraft dropped 3,138 tons of bombs. Three older submarines, two liners, and 10 other ships were sunk.
  • The British were also busy over Kiel. On the night of April 8–9, 427 bombers dropped 1,503 tons of bombs. Five commissioned Type XXI submarines and five merchant vessels were sunk. Nightly raids by Mosquitoes were carried out from 21 to 27 April.
  • Kiel was attacked again on the night of 14–15 April by 467 British bombers. Seven older and two Type XXI submarines were sunk in the British raids and the facilities were practically destroyed in the combined raids.

Raids not directly linked to the air campaign against the new submarine facilities were also damaging. For example, the bombing of factories in Hanover and Hagen destroyed the production plants for batteries. The only other plant producing batteries for the submarines was at Posen and it was captured by the Soviets in January 1945. The Soviet advance also stopped all work at the submarine assembly yard at Danzig. Churchill writes that the Soviet capture of Danzig, one of the three principal submarine bases, was a great relief to the British Admiralty. He observed that the resumption of the submarine war on the scale envisioned was clearly impossible.

The production of the smaller Type XXIII was not nearly as affected by Allied bombing as the Type XXI. Only five of these boats were destroyed by bombing. There were two reasons for this lesser damage. First, the assembly site in Hamburg was sheltered in hardened concrete bunkers. Second, the other assembly point in Kiel was not heavily damaged by bombing. However, the output of these boats dropped off because the supply parts dried up. The production dropped from nine boats each month in 1944 to four in February 1945.

Dönitz, with his single-minded focus on the submarine war, was probably one of the very few among the senior German leaders who still believed in early 1945 that the war could be turned around. He was repeatedly forced to explain to Hitler why the 1943 production schedule was continually falling behind. In these “excuse” sessions he always maintained that the turning of the tide was just around the corner, when he knew that was not the case. Hitler would not have tolerated this from his generals, but Dönitz had apparently ingratiated himself to Hitler in such a way that it was tolerated. His optimistic approach to a person who faced disasters on all fronts may be one explanation. Their ideological compatibility was undoubtedly also important. Raeder, Dönitz’ predecessor, met with Hitler infrequently, but Dönitz became practically a fixture at Hitler’s briefings and conferences.

Dönitz had focused his entire naval strategy during the last two years of the war on the deployment of the new submarines. While the Germans came up with a design that profoundly influenced future submarine designs, their immense efforts did not help them turn the tide in World War II. The most promising new boats—Type XXIs—never launched a single torpedo at an enemy.

Japanese Naval AAA Early War

Japan developed naval radar to a far greater extent than her Axis partners, because her fleets spent much more time in contact with enemy fleets and enemy aircraft. Unlike the Germans, the Japanese pursued both metric-wave and microwave technology. They did not develop the powerful magnetrons which made British and US microwave radar fully effective (output was typically half a kW rather than the hundreds of kW of the Western sets). Also, because the first radars they saw (in Germany) were air-search sets, the Japanese were inclined to begin with that type of radar rather than, as in the German navy, to limit themselves to fire-control sets. The first two installations were on board the battleships Ise and Hyuga, prior to Midway. Meanwhile US and British metric army radars fell into Japanese hands at Singapore and in the Philippines.

The first major operational sets were a metric air-search radar (Type 2 Mk 2 Mod 1) and a microwave surface-search set (Mk 2 Mod 2, a developmental designation). Mk 2 Mod 1 had a mattress antenna. On a carrier it was typically free-standing; on a battleship or cruiser it was on the foretop. Range on an aircraft was 70 to 100km (38 to 54nm). Because there was no Japanese PPI scope, the surface-search set was also treated as a fire-control rangefinder.

After the battle of the Philippine Sea, the Naval General Staff ordered all surviving ships equipped with both an air-search set (Type 3 Mk 1 Mod 3) and a surface-search set (Mk 2 Mod 3, with increased power [10 kW]). Type 3 Mk 1 was a new set, development of which was completed only in February 1944, based on a land-based radar. The great deficiency was a complete lack of anti-aircraft fire-control radar. There were also airborne radars, including sea-search sets. Unfortunately they were heavy. Thus during the battle of the Philippine Sea Japanese torpedo bombers equipped with Mk 6 radars were ordered to remove them: they could not lift both the radar and a torpedo.

The pre-war Imperial Japanese Navy was determined to maintain radio silence, which to the higher staff included radar silence. That view stopped radar development for a time before the war, when it was first proposed, and the ban on emissions (until ships were under fire) was not completely lifted until the spring of 1944, just before the battle of the Philippine Sea. By that time ships had been lost under circumstances suggesting that they would have survived had they had air warning. The battleship Musashi had been damaged by a surprise attack while steaming from Japan to Palau in the latter part of February 1944. The cruiser Atago had given a practical demonstration of the value of radar. During repairs after Guadalcanal, the Communications Officer of First Fleet convinced his superiors to mount an early Mk 2 Mod 2 microwave surface-search set aboard the cruiser. The radar was credited with the survival of seven cruisers after the battle of Empress Augusta Bay in November 1943.

In the 1930s, like the US Navy, the Imperial Japanese Navy considered its carriers both powerful and vulnerable; the question was how to use them most effectively before they could be destroyed. The initial answer for both navies was dispersal. Thus a November 1936 Staff College study called for dispersal of the carriers so that they could envelop an enemy force. The largest carriers would steam alone, the smaller ones in dispersed formations so that they could combine to provide sufficient striking power. The paper emphasised the need for greater range than the enemy’s, a continuing theme later on.36 The experience of war in China seems to have convinced the Imperial Navy that only by massing could it realise the offensive power of its carriers. The 1939–40 fleet exercises employed co-ordinated air group attacks. Since it was essential not to reveal the positions of the carriers, the Japanese saw little point in using radio to co-ordinate dispersed ships. They had to be within visual range if their air groups were to work together. The compromise solution reached in 1940 was for the carriers of each division to concentrate, but the divisions to disperse so as to envelop the enemy.

The Japanese Navy was the first in the world to concentrate all the aircraft of several carriers into an integrated Air Fleet. By May 1941 it had a multi-carrier operational doctrine. By this time, at least as conveyed to the contemporary Royal Italian Navy by a high-level Japanese mission, the Imperial Navy considered the enemy carriers its prime target, since once they were sunk the enemy’s naval force would be deprived of essential air services: search, attack, and fighter defence. Once the carriers were gone, the enemy fleet would lose about half its fighting potential. Conversely, great attention had to be paid to safe-guarding the Japanese carriers. The Japanese seem to have envisaged a two-phase battle, the carriers first destroying the enemy carriers, and the main body (surface force) then engaging the enemy’s surface force, the unstated assumption being that carrier aircraft probably could not sink the enemy’s battleships. That was a logical assumption at the time, given the large number of torpedoes a modern battleship could absorb and the ineffectiveness of dive-bombing armoured decks.

Each Japanese task force (a phrase used in the 1941 Italian notes) would have attached to it a carrier division of up to three carriers. At this stage there was no expectation of unifying the air groups. Instead, the idea was to specialise – to place all the fighters on one carrier, the dive bombers on a second, and the torpedo bombers on a third. It was understood that specialisation might be dangerous, but until the two fleets engaged the only real danger was submarine attack, which was considered minimal. Apparently Japanese doctrine also allowed for mixing different types on each carrier, but that was considered an inferior solution. All-fighter carriers would be responsible for protection of non-fighter carriers, but carriers with mixed air groups would be at the direct disposal of a task force commander both to protect the main body and for use during the surface battle and subsequent pursuit.

The carriers had to be separated from the main body – the surface force – so that they were unlikely to fall victim to enemy light or heavy ships. Prevailing wind, for launch or recovery, would determine where the carriers might be placed. In the simplest formation, the carriers were about ten miles ahead of the main body, with attached destroyers for submarine protection and cruisers to protect them from enemy light forces. Once combat was imminent, the carriers would move so that the Japanese main body was between them and the enemy, beyond gun and torpedo range (a 1941 diagram showed the carriers 20–25nm off the track of the Japanese main body, with 20nm a bare minimum).

The emphasis on fighter defence of both the carriers and the main body suggests that by the spring of 1941 the Imperial Japanese Navy had limited faith in its anti-aircraft guns – which was much the position of the US Navy at the time. However, by 1941 the Imperial Japanese Navy was building Akizuki class destroyers which may have been intended specifically to provide anti-aircraft support to carriers. The provision of the destroyers may have reflected fear that it would be difficult to spot high-performance attackers in time. Carriers, like capital ships, were well armed with anti-aircraft guns. Overall the Japanese seem to have had much the same view of carrier survivability as the US Navy: carriers were eggshells armed with hammers. Fighters were the only real defensive option, but attackers would probably succeed. That is certainly what happened in the 1942 carrier battles.

It is not at all clear that the Japanese had thought through the requirements of fleet air defence. The standard carrier fighter complement was eighteen aircraft, nine of which were expected to accompany its strike aircraft. Without reliable voice radio, and without radar, fighter direction could not even be imagined. The standard fighter formation was the three-plane shotai. In theory a carrier would maintain a shotai continuously aloft (with two-hour endurance), keep another on deck alert and a third at a lesser readiness. If an attack developed, the two reserve units would be launched to supplement the one aloft. Individual pilots had assigned sectors. In theory, further aircraft could be vectored to a threatened sector, but little attention went to direction of any kind.

Carriers were grouped together as an integrated force (mobile aircraft force) for the first time in the June 1940 manoeuvres, and on 1 April 1941 two carrier divisions were formed into the 1st Air Fleet as a unified entity. By the time of Pearl Harbor six carrier air groups had been integrated together. In such a force each carrier had its own mixed air group. That presented a new operational problem, as each carrier would have to launch and recover aircraft more frequently, usually manoeuvring into and out of the wind. Like the contemporary US Navy, the Imperial Japanese Navy seems to have concluded that carriers should be well separated to this end. Separation would also make it more difficult for an enemy to find and attack all of the carriers. Separation in turn made it impossible to provide the destroyer screens previously envisaged. Instead, each carrier was assigned two plane guard destroyers. Carrier survival would be based on manoeuvre (evasion) and dispersal (an enemy strike should not find all of them together).

Given their First World War experience working alongside the Royal Navy, it seems likely that the Japanese adopted the British emphasis on radio silence for security. On that basis it is not clear how well air operations from separated carriers could be conducted. It would be much simpler to concentrate a pre-arranged strike than fleet air defence. Fighter defence seems to have been conducted by a strong CAP, without any form of fighter direction. It does appear that the Japanese hoped for early warning provided by lookouts on board dispersed surface ships.

Given limited faith in fleet anti-aircraft firepower, ships could manoeuvre freely to evade attack, even though that would ruin fire-control solutions. The Japanese adopted a standard circular evasive manoeuvre, familiar from photographs of Japanese ships under attack, from Shoho at the Coral Sea onwards, had the important virtue that it might frustrate dive bombing, as an attacker would find it difficult at best to compensate for a radically varying aim point and with the changing effect of wind as the ship moved. At least one US officer espoused exactly this manoeuvre in 1942. Note that if all the ships in a formation began to circle at high speed, the formation would break up. That was probably acceptable given that there was apparently little interest in mutual support other than by integrating the air groups of carriers working together. It is not clear whether the circular manoeuvre was adopted pre-war or during the war.

Thus the Akizuki class, armed with four twin 10cm/60, and specifically intended for anti-aircraft screening, seemed to contradict evolving Japanese carrier thinking. The first six were inserted into the naval programme as modified in December 1938, under the designation ‘direct protection’ destroyers. As sketched they would displace 2600 tons, with a speed of 34kts, armed with four twin 10cm, four 25mm and a bank of four torpedo tubes. The light torpedo battery testified to their unconventional mission. They were described as close protection for carrier divisions. The projected Maru 5 and Maru 6 programmes planned in 1941 included a new class of anti-aircraft cruisers, to displace about 5000 tons and to be armed with six twin 10cm guns. However, they were not included in the programme as projected in the spring of 1941. Instead, it included sixteen improved Akizukis (2900 tons, design F-53). The other sixteen destroyers in the programme were of more traditional (Shimakaze) type (a repeat pre-war type was eventually built).

The Japanese distinguished three types of operation. One was the massed strike against a land target, as at Pearl Harbor. In that operation the carriers occupied a box about 8km on a side, the distance providing sufficient sea room for the carriers. The six ships which struck Pearl Harbor were in two widely-separated staggered columns, with screening ships around the box. Much the same formation was adopted for Midway, the only major difference being that there was columns of two rather than three. In the Indian Ocean operation (March/April 1942), the major units were in line ahead, the head of the column being a bent screen of destroyers with a cruiser on either flank. This formation would make sense (as in British operations in the Mediterranean) if the object was to clear a corridor of submarines.

A second type of operation was a fleet vs. fleet battle, as at the Coral Sea. Carriers operated loosely co-ordinated, each having only plane guards in company. The surface force (the main body) would be nearby but not too close. Probably the Japanese had learned from pre-war exercises that it was much easier to spot a large surface force from the air, and that carriers should not be so close that any scout spotting the surface force would also see them. That was much the lesson the US Navy had learned pre-war.

At Santa Cruz battleships and cruisers formed a vanguard formation, with the carriers about 100km astern. This vanguard was largely line abreast, which suggests it was a scouting formation, except that it had a pair of Kongos in line ahead at its centre. The four carriers were in loose formation, the carrier Shokaku leading her sister Zuikaku by about 8000m, with Zuiho 8000m to one side and Junyo 100 miles away (originally she was to have had Hiyo with her, but that ship had to retire due to an engine fire). Each carrier had two plane-guard destroyers as her only escorts. Compared to the Eastern Solomons, the carriers were considerably further astern of the vanguard. This combination of Main Body and Advance Force was used again at the Philippine Sea in June 1944. A third type of operation was direct support of a surface force, a single carrier being more or less integrated with the surface force. That was the case of Shoho at the Coral Sea, with cruisers in company.

In August 1943 Combined Fleet issued a memorandum explaining that for future operations it was necessary to have a standard set of operating procedures and doctrines. At just about the same time the US Navy was developing its own set of standardised procedures under the designation PAC-10 (or USF-10A). Both navies had to deal with the disintegration of the pre-war fleet. In the US case, the flood of new construction (and new air groups) could be absorbed only in standardised forms, so that each new ship or squadron knew where it fitted in. In the Japanese case, the pre-war navy understood enough that limited orders sufficed. Enough of that fleet was destroyed, particularly in the Solomons, to bring up officers who had not absorbed enough standard procedures pre-war. Like their US counterparts, they needed standardised procedures laid out explicitly. Probably the doctrines involved were not too different from those of the past, but the officers of the past did not need such explicitness. At about the same time the Japanese introduced circular screening formations for carriers, mainly for protection against submarines (almost no Japanese destroyers had area anti-aircraft capability). No other surface combatants were involved, and multicarrier formations were not envisaged; this was not contemporary US circular-screen practice.

A May 1943 paper on strike force tactics drew the lesson of the 1942 carrier battles: ‘the secret … is to divert and restrain the enemy on one side, and then to attack suddenly from the flank. This discovery was a product of chance in successive battles. We must deliberately develop such situations and, advancing, destroy the enemy on the field of battle.’ That changed the likely role of the heavy surface group from a hammer against the enemy’s surface ships (and damaged carriers) to a means of diverting his attention from the carriers, which were now to be the hammer. The May paper advocated forming a diversionary force comprising a battleship division and decoy carriers. The latter could be useful only if they were used aggressively, hence had to be fast. A light cruiser, for example, might be camouflaged to look like a carrier. Official doctrine promulgated in March 1944 went further. The Advance Force of the past (the heavy surface force) was renamed the Diversionary Attack Force in line with current thinking. This logic was inverted at Leyte Gulf, the carriers, almost bare of aircraft, acting to divert attention from the heavy attack force approaching invasion shipping.

The new doctrine emphasised air attack against the enemy’s carriers, not only as a means of reducing the enemy’s overall strength prior to a surface battle, but as the main part of a battle. In the face of enemy aircraft, the fleet would retire quickly and reorganise. That made sense, since the Japanese could expect to outreach the Americans, striking first to (they hoped) destroy US carriers and their aircraft. Only if the US Navy achieved surprise (due to a failure of Japanese scouting) or managed to wipe out the Japanese air strike force (as happened at the Philippine Sea) would the Japanese carriers see US carrier aircraft. Alternative fleet dispositions were a concentration of all three carrier divisions, a concentration of two with a third carrier division at a distance, and three separate carrier divisions. Since relatively few surface ships operated with each carrier or carrier division, the Japanese did not feel any pressure to consolidate the carriers into US-style formations.

Japanese Naval AAA Late War

The 1944 instructions include anti-aircraft fire: barrage fire is to be used both against dive bombers and against low fliers. That is much the British doctrine of this period, and it suggests that, like the British, the Japanese did not expect to use aimed fire against other than high-flying level bombers. Ships escorting carriers were to concentrate on defending the carriers.

All of this meant that, as unpleasant as Midway had been, the Philippine Sea carried the additional message that the enemy would almost always be able to carry out his air attacks unhindered by any long-range Japanese strike. Anti-aircraft weapons suddenly became far more important, because the option of striking first at greater range was gone. That had already happened in 1942, but in 1944 the Japanese could hope to regain their range advantage with new carrier attack aircraft.

After Midway, Admiral Yamamoto issued new orders for ships under air attack. Battleships were taken as the basis for more general practices. The ship in the fleet closest to the attacking aircraft was to turn towards the enemy and emit specified smoke signals, firing its guns so as to direct Japanese fighters towards the enemy. Presumably smoke was to be used because the Japanese had taken from the British the idea that radio silence was golden. However, the orders also included flag and wireless signals to provide data such as the strength of the enemy force. Their list of ways of detecting incoming enemy aircraft consisted of radio intelligence, radio location (presumably radar), scouting aircraft, watching aircraft and fire-control predictors (presumably used to project forward the path of enemy aircraft).

Alternative means of distributing fire among ships of the fleet were given. The rules clearly envisaged British-style barrage fire by the main and secondary (LA) batteries, which could be used against torpedo bombers, long-range bombers, and bombers capable of strafing (presumably a literal translation), but primarily against torpedo bombers. Medium-calibre anti-aircraft guns would be used against bombers and dive bombers. Machine guns would be used against dive bombers and, according to circumstances, short-range torpedo bombers.

Special rules indicated when guns could open fire in the presence either of numerous or few or no Japanese fighters. For example, when there were numerous Japanese fighters, guns could open fire against torpedo bombers out to 15km range. They could open fire against dive bombers when they were running in – at an estimated altitude of 3000m (9840ft) and at a 50° vertical angle. Against low-level bombers, the range to open fire depended on whether there was an adequate patrol on the second warning line. If there was, fire could be opened not more than 5km (plan range) from the second line. When the patrol at the second line was inadequate, fire could be opened 6nm (unit given) from each ship. Fire could also be opened when the enemy aircraft were at an altitude of more than 6km (19,700ft) and 7km (7650 yds) from the ship (plan range).

An appendix warned that sights etc on all types of AA guns were unsuitable for use against fast aircraft moving at 200kts or more, and should be rebuilt.49 Simple unobtrusive sights suited to 300kt targets could be placed alongside the existing sights of 12cm and 7cm AA guns. The ordinary sight of the 8cm AA gun should be improved and a simple unobtrusive sight suitable for 300kt speed should be fitted. Measurement and gradation of the firing table for the Type 89 (12.7cm) AA gun and the time taken for communication were considered excessive; a simple and rapid type of measuring instrument should be made and distributed. Automatic weapon (25mm and 13mm) sights could not match target speed, as their capacity was too limited, and therefore they could not be used in combat. Either a prism should be inserted in the sighting telescope, or a simple 300kt sight should be installed.

A drawing of a typical battleship AA battery clearly showed a Yamato class battleship, but that must not have been evident at the time. Main and secondary gun calibres were not given, but the ship clearly had two main battery turrets forward and one aft, plus four secondary battery mounts in diamond arrangement. The diagram showed three AA guns (actually twin 12.7cm) on each side, numbered odd to starboard and even to port. Also on each side were two ‘concentrations’, each apparently corresponding to a pair of light anti-aircraft mounts, which were controlled together: one each at the ends of the row of medium AA guns. Another machine gun mount was on each side forward of the middle AA gun, for a total of ten machine gun mountings. All were mounted inboard of the medium-calibre guns.

A US Navy evaluation of Japanese AA fire in mid-1944 was that medium-calibre guns were being used for barrage rather than aimed fire. Most aircraft were being damaged by guns in the 20mm to 40mm class, the 25mm Hotchkiss being the most effective. Guns of 20mm to 40mm calibres had caused three times as many casualties as those of heavier calibres and six times as many as many as guns of lighter calibres. That was contrasted with US experience in which 5in guns had overtaken the lighter weapons in lethality. A captured document gave ranges to open fire for various calibres: 9900 yds for the 12cm (4.7in), 7700 for the 3in, 6600 yds for the 8cm, 2750 for the 25mm, and 2200 yds for the 13mm. All but the last were in line with ranges at which the British and the US Navy expected fire to become effective; the 13mm figure was more than twice that adopted by the Allies. It seemed that the Japanese were relying on a course and speed sight (like the Le Prieur sight of the 25mm gun and its director) to an unrealistic degree. The same document stressed the need to conserve ammunition, hence to limit the number of rounds fired at any one target. Limits given were six rounds for a 12cm gun, ten for 8cm, and one magazine (fifteen rounds for a 25mm gun) for machine guns. Automatic weapons were not to fire at retiring targets (a policy also followed by the Allies). The severe restriction on numbers of rounds to be fired reflects production problems even before Japan began to suffer strategic bombing. The figures were far below the RPB estimated for US guns.

After Midway the Imperial Japanese Navy decided that its Type 94 fire-control system was inadequate even with planned improvements, so work began on a new Type 3 (1943) system. Like Type 94, it had its rangefinder in the director, which was arranged to insure that layer, trainer and control officer were all observing the same target. Like many wartime British systems, it had scooter control for rapid slewing by the control officer. Very rapid development, and many system features, suggest that Type 3 was inspired by British systems such as the FKC, details of which were probably captured at Singapore. Like the British systems, Type 3 worked in terms of plan motion, the target being handled as though it was flying at constant altitude. Thus, unlike Type 94, Type 3 used rectangular co-ordinates. Also like the British systems, this one included a height plot intended to allow an operator to estimate aircraft height from a scatter of observed points. Unlike British systems, the director was sufficiently stabilised (by leveller and cross-leveller, not gyros) that it was expected to provide accurate bearing data. The Japanese later said that Type 3 was designed to provide rapid solutions. Initial inputs were estimated target course and speed (as in British systems). Unlike Type 94, Type 3 worked in rectangular co-ordinates, decomposing target speed into across and along components. To avoid the use of three-dimensional ballistic cams, it employed a British-style roller on which firing table data were engraved. The computer turned the roller, and an operator found the appropriate tangent elevation on it, sending it to the guns by means of a follow-up. A similar roller was used to enter wind corrections. Ballistics could be changed simply by replacing the rollers. Type 3 was never completed, although manufacture of a prototype was well underway at the end of the war. It was not related to the Type 3 developed for use ashore.

There was also an attempt to produce a dual-purpose destroyer system to control 12.7cm/50 guns. This Type 2 (1942) system replaced pre-war LA fire-control systems. Unlike Type 3, it entered service, but was never considered satisfactory for HA fire. The Japanese described it as grossly over-complicated, because its designers refused to compromise by emphasising either HA or LA fire (i.e., large or small angular rates). Instead, the same mechanism was used for both high and low angles, with change-over gears and clutches to shift function. Change-over required a complicated lining-up procedure. The associated Type 2 director was fully enclosed and trained hydraulically, but the optics were not cross-levelled (director outputs were adjusted for cross-level). On top it carried a 3m rangefinder which could train independently. In addition to the usual pointer and trainer it carried a target inclination operator (Japanese surface fire-control systems included elaborate inclination devices). The computer maker, Aichi, considered the associated Type 2 computer the most complicated it had ever made. Prediction was based on rate integrators. The computer used a three-dimensional cam to correct LA elevation to super-elevation for HA fire.

By 1944 there was an urgent requirement for a radar director to replace the Type 2 director; the result was the Type 5 (1945) director, which was intended as a minimum modification to Type 2 for destroyers and light cruisers. The Japanese described it as a means of blind fire, but that was not true in Western terms, since their radars did not provide good enough bearing and elevation data. Type 5 never entered service.

The standard Type 95 machine-gun director was modified with scooter control (probably based on British technology acquired when Singapore fell). By the end of the war the associated ring sights provided for target speeds of 900, 800 and 700km/hr (900km/hr equated to 492kts). Given production problems, a simplified version was produced, designated Type 4 (1944) Mod 3. It had range rings only for 800 and 700km/hr (800km/hr is 437kts), with a central area to be used for speeds of less than 600km/hr (328kts).53 Because the new device was simpler, it was available in larger quantities, and it could be used more extensively, and also ashore. Initially it was intended for 12cm rockets (see below) in addition to 25mm machine guns, but use was later extended to the war-built Matsu and Tachibana class escort destroyers.

Massive anti-aircraft rearmament began in the spring of 1944. The two superbattleships had their wing 6.1 in anti-destroyer mounts replaced by anti-aircraft weapons. Many 25mm guns were added. For example, in the superbattleships the original 25mm mountings were in closed shields to protect them from the blast of their 18.1in guns. The new mountings were the standard unshielded type. The big fleet destroyers had their after superfiring twin 5in guns replaced by triple 25mm guns. Note that, unlike fleet destroyers, the Matsu and Tachibana class escort destroyers all had 12.7cm/40 guns, which were truly dual-purpose.

Two new weapons were deployed. After a short development programme, 12cm anti-aircraft rockets were deployed in 28-round launchers on modified 25mm machine-gun mounts, controlled by standard 25mm machine-gun directors. These launchers were installed on board the battleships Ise and Hyuga and on board several carriers including Zuikaku. These shrapnel incendiary weapons were used at Leyte Gulf, but results were not recorded. The Japanese did say that they valued them as a deterrent and as a way of increasing anti-aircraft firepower at relatively low cost – much as the Royal Navy had adopted rocket weapons in 1940.

The second new weapon was the Model 3 incendiary anti-aircraft shell, which was fired by low-angle guns up to and including the 18.1in guns of the two superbattleships. Shells were filled with steel tubes containing an incendiary mixture. The shell was burst by a mechanical time fuse, the tubes igniting about half a second later, burning for 5 seconds. An alternative Model 4 was phosphorus-filled. Much effort was directed at production of these shells during the run-up to the Guadalcanal campaign. Gunnery officers considered these shells more effective than the usual common shells when fire was directed at approaching targets, because the tubes and fragments formed a cone beyond the point of burst. The post-war US view was that the officers were misled by the impressive appearance of bursts; the projectiles were apparently ineffective. Among other problems, the ballistics of the special shells was different from that of standard HE. Moreover, the shells should have been burst higher than HE shell, because shrapnel drops as it is ejected by the shell. Gunnery officers were given special ballistic charts and cards giving the necessary corrections. In many ships, some turrets were loaded with HE and some with incendiary shrapnel, to be prepared to engage either approaching or retiring targets.

There was also an attempt to improve the performance of anti-aircraft guns by improving and streamlining the shells. By the end of the war, tests had been completed on the destroyer 5in shell, the standard 4.7in shell, and the 3.9in shell, of which the 4.7in had gone into production.

Under post-war interrogation, the Japanese professed themselves satisfied with their anti-aircraft weapons. Few records of shipboard performance had survived, so most naval records were of the air defence of Japan itself. The subject is complicated further by the fact that, during and after the Bougainville Island engagement, the Imperial Japanese Navy was extremely short of ammunition. As a result, it shot down many fewer aircraft. For example, 25mm machine guns were limited to ten rounds per plane against diving targets, fire being held until the aircraft closed to 1000 metres. The Japanese claimed that US aircraft were so predictable that such figures were adequate, but it turned out that they grossly overclaimed aircraft shot down. The one ship figure which emerged in interrogation was that the carrier Zuikaku, armed with three twin 12.7cm guns and sixty to seventy machine guns required 150 RPB with her 12.7cm and 1000 RPB with her 25mm at ranges of 1000 to 2000m in the South Seas Battle (presumably Philippine Sea). These were not far from generally accepted figures, which may represent hoped-for rather than achieved standards. The Japanese also stated that effective range for the 12.7cm anti-aircraft gun was 8000m and below 3000m altitude, and for the 25mm machine gun, 2000m range and 1000m height (1500 RPB). Attempts were made to predict the effectiveness of various weapons, but they were not backed by operational data of the sort used by the US Navy. Other remarks made under interrogation were that no planes were claimed by 10cm and heavier batteries for ranges beyond 8000m, and the best results were obtained at 4000m and below. For medium ranges between 4000 and 7000m, the 10cm high-velocity gun was considered the best medium-calibre weapon. No kill claims were made for ‘jinking’ targets.

Papal Navy (Eighth-Nineteenth Centuries)

Capitana Pontificia (flagship of the Papal Navy which fought at the Battle of Lepanto, 1571)

An occasional force in the containment of Islam. From the early eighth through the late nineteenth centuries, what can be termed a papal navy existed sporadically. The chief purpose for such a navy was to halt the spread of Islam in the Levant and the Mediterranean. This navy was, more often than not, a collection of men and ships subsidized or authorized by the papacy but operated by other Christian powers to support papal policies.

For centuries the Muslim Saracens raided Christian territories and captured them to use as slaves. Popes and emperors were concerned about such depredations but usually did not maintain any type of standing force to stop them. There were a few exceptions. In 877, for example, Pope John VIII raised a fleet of galley-like ships, known as dromone, to defend Christian interests. This fleet, however, was short-lived and did not solve the problem.

After the popes preached the crusades, a renewed interest in building naval assets to further this effort emerged. In 1201 the Venetians agreed to transport the crusaders of the ill-fated Fourth Crusade to Egypt, whence they would then launch themselves on the road to Jerusalem. This crusade went awry, and the crusaders seized first a portion of the Adriatic coast and then Constantinople itself, but it illustrated how the pope might put naval resources to use.

In 1213 Pope Innocent III authorized King Philip II (Augustus) of France to cross the English Channel and invade England, after he had excommunicated King John and declared him deposed. This invasion did not occur, as John made amends and Innocent lifted the ban; but, again, this was an instance of papal intent to use a naval force.

With the fall of Constantinople to the Ottoman Turks in 1453, papal concern over possible Islamic domination increased. Pope Pius II (1458-1464) wanted to create an actual papal navy that might stem the Islamic tide. This navy did not materialize, but the pope believed a need existed and hoped to lead the charge against Islamic expansion into Europe.

One of Pius II’s successors, Pius V (1566-1572), brought the concept of a papal navy to its highest point. On his election in 1566, Pius V immediately provided funds to Philip II of Spain to strengthen the Spanish Navy in order that it might contain the Turkish fleet, which then threatened to dominate the Mediterranean. Spain, the Holy Roman Empire, and the papacy had a common interest in suppressing the Islamic impulse, but France and England had their own strategic interests vis-a-vis the Spanish and Catholicism respectively. Thus, the leaders of the Christian world were divided. By 1570, however, Pius V had emerged as the dominant voice in anti-Turk negotiations, and he brought the Venetians into the fray. These negotiations resulted in first a temporary alliance with papal subsidies for the Venetian navy and then a formal alliance in early 1571, the Holy League.

Ultimately, the Holy League went to war against the Turks and defeated them in the greatest battle of galleys since Actium, the 7 October 1571 Battle of Lepanto. It was, unquestionably, the high point of the papal navy. The Christian fleet at the battle comprised 207 galleys, 6 galeasses, and 24 cargo vessels. All but a few were from the pope. The Ottoman fleet was made up of about 250 galleys. The Christians had upwards of 44,000 seamen and 28,000 soldiers from Venice, Spain, Genoa, Savoy, Malta, and the Papal States. Turkish seamen numbered some 50,000, along with some 25,000 soldiers. The casualty count, both in men and ships, is widely disputed, but the Turks lost over 200 galleys and 20,000 dead. The Christians put their own losses at 12 ships, with 7,500 dead and 15,000 wounded.

Although the Ottoman fleet was rebuilt, after the Battle of Lepanto the papal navy was essentially involved with curbing the activities of Muslim pirates who haunted the waters of the Mediterranean until 1830. A papal navy, either subsidized or authorized, managed to survive until the late nineteenth century when Pope Leo XIII (1878-1903) dismantled it as a useless vestige of the times when the popes competed stridently for temporal power.

References Braudel, Fernand. The Mediterranean and the Mediterranean World in the Age of Philip II. Vols. 1, 2. Trans. Sian Reynolds. New York: Harper & Row, 1966. Guglielmotti, P. Alberto. Marcantonio Colonna alla battaglia di Lepanto. Firenze: Felice Le Monnier, 1862. —. Storia della Marina Pontificia. Vols. 1-10. Rome: Tipografia Vaticana, 1886-1893.

Papal Naval Flag