On 12 March off West Schouwen a fighter-bomber gunned Lt Böhme’s boat. It burned and both crew perished.
On their return to base in U-5064, Kugler + Alois Schmidt reported having sunk a steamer of 3,000 to 4,000 tons.
On 10 March SKL had decided to use Seehund submarines to supply the starving German garrison at Dunkirk. K-Verband Command received orders to fit out three boats to carry transport cylinders of provisions, batteries, limpet mines and mail. The boats were to be ready at Ijmuiden on 15 March.
On their return to base on 13 March, Fröhnert + Beltrami reported having sunk a steamer in the Thames estuary. They had also survived a depth-charging.
The same day U-5377 was lost, von Neefe und Obischau + Pollmann were saved: U-5339 (Kempf + unknown) was depth-charged and sunk off Buoy NF5: off Harwich on the same day a Seehund ran into five boats of 165th Minesweeping Flotilla and after being forced to dive in a hail of 2-cm and 7.5-cm followed by depth-charges, the boat was lost at position 52°01′24″N and 01°53′24″E.
None of the three Seehund known to have been off Margate on 16 March returned. On 18 March B-Dienst reported a British signal describing large quantities of oil and wreckage found near the Margate coast, and four empty lifeboats. What ship this was and its cause of loss remains a mystery.
On 21 March in light fog, U-5366 (Hauschel + Hesel) discovered a convoy assembling in grid square AN 7663 between Lowestoft and Great Yarmouth. At 0330 Hauschel torpedoed a Liberty freighter which exploded three minutes later. The whole sea was lit bright as day, the victim must have been carrying munitions. U-5366 touched bottom at Egmond aan Zee during the night of 24 March but reached Ijmuiden undamaged.
Gaffron + Köster got caught up in a battle between German S-boats and British MTBs and MGBs on 22 March. The Seehund was fired on and the tower was damaged, making the boat undiveable. The crew abandoned and were picked up by the British. The same day Göhler + Kässler were attacked and sunk by a fighter-bomber shortly after leaving Ijmuiden.
At 0452 on 22 March, MTB 394, while lying stopped on listening watch about 23 sea miles south-east of Great Yarmouth, was rammed by a Seehund. The British opened fire into the mist, heard cries for help and picked up two German submariners.
At 1920 on 24 March U-5264 fired two torpedoes at a destroyer near the South Falls sandbanks and missed.
On 25 March the British motor launch ML 466 was torpedoed by a Seehund and exploded. There were no survivors. The attacker may have been the boat of Meyer + Schauerte which had left Ijmuiden two days previously and failed to return, although Wagner + Wegner or Plottnik + Mayer who were in the area on 24 March are also possibles.
At 1200 the same day Warnest + Nöubeling came under attack from motor launch ML 1471 near Tamarisk Buoy. Warnest decided that attack was the best form of defence and responded with two torpedoes which missed. He escaped, however, and returned to base.
On 26 March in grid square AN 7956, Küllmeyer + Raschke torpedoed the steamer Newlands, 1,556 tons, which sank at once. The boat returned to Ijmuiden on 27 March.
On 25 March at 1440 Beaufighter Q of RAF 254 Squadron sank a Seehund about 17 sea miles north-west of the Elbow Buoy.
At 0231 on 26 March the escort destroyer HMS Puffin pinpointed a Seehund by Asdic about seven sea miles off Buoy 4. The submarine surfaced, rammed the stern of the destroyer, slid along the hull and exploded, tearing a great hole in the destroyer’s forecastle, damaging the keel. Puffin remained afloat and picked up the two Germans from the water. After an inspection ashore, the destroyer was declared a constructive total loss.
On 27 March ML 586 sank a Seehund west of Walcheren.
On 30 March a Seehund sank the coaster Jim, 833 gross tons southeast of Orfordness. Twelve of her crew of twenty survived. Another Seehund was sunk by the harbour defence vessel HDML 1471.
On 27 March three Seehund left Ijmuiden to supply the German garrison at Dunkirk. The boat of Fröhnert + Beltrami began to food and being undiveable returned to base. They sailed again the following midday. Weather was extremely bad with enormous seas. The storm lasted seven days: Fröhnert’s boat reached Dunkirk on the last day of the tempest and was guided through the coastal minefield by the stern light of a naval trawler. Both crewmen were admitted to the military hospital with exhaustion. After their recovery they were received by Admiral Frisius. On 9 April they sailed, and reached Ijmuiden despite air attacks and a flooded diesel.
In summary it may be said that the fighting between hunters and hunted became particularly bitter and resolute in March 1945. Seehund boats sank or damaged five steamers of about 15,000 tons. A patrol boat was torpedoed and a destroyer written off as a total loss after being rammed. On the debit side, 5 K-Division lost at least 15 Seehund and 30 men dead or prisoner.
Before the beginning of April 1945, Anglo-American forces reached north-west Germany and were virtually surrounding Festung Holland. Additional Seehund at readiness in Wilhelmshaven naval base and U-boat bunkers on Heligoland island prepared to sail for Holland, transport by road or rail being no longer possible. Heavy air attacks on K-Verband bases caused damage to buildings but the midget submarine force escaped unscathed. After the weather improved sorties were sailed from 4 April with great determination. By the end of the month 36 individual missions had been been sailed to the English east coast, the Scheldt Esturary and to Dungeness near Dover.
On 8 April, 5 K-Division had 29 boats at Ijmuiden, only half of them operational. Four others arrived on 20 April, 14 on 1 May from Wilhelmshaven, and another two from Heligoland.
Two boats sailed, one each on 5 and 6 April respectively, for the Thames-Scheldt route. U-5366 (Hauschel + Hesel) returned on 8 April with no successes to report, the other boat was sunk, probably on the 6th. Nine Seehund sailed at 2130 on 7 April to attack convoys between Dungeness and Boulogne. Bischoff + Hellwig failed to return and were presumed killed in action on 19 April. U-5332 (Wolter + Minetzke) ran aground at Calais. After destroying the boat, they surrendered. Rosenlöcher + Musch remain missing. The boats of von Pander + Vogel, Ross + Vennemann and U-5074 Schöne + Sass returned to base, the latter boat being undivable after a Martin Marauder bombed it at 0630 on 8 April.
The operations of these and a number of other boats can only be assembled in fragmentary form:
9 April, 0531. A Seehund torpedoed the tanker Y17 from convoy TAC 90 eight cables off North Foreland Buoy NF5. The tanker burst into fl ames after an explosion and sank. There were no survivors.
9 April: Near Dungeness, Buttmann + Arno Schmidt attacked convoy TBC 123. Buttmann sank the freighter Samida, 7,219 gross tons with one torpedo, and seriously damaged the US freighter Solomon Juneau, 7,116 gross tons, with the other. The Seehund was subsequently sunk by ML 102 east of Dover. The body of Schmidt drifted across the North Sea and washed up on the island of Föhr, to be interred at Wyk cemetery.
Another Seehund was sunk this day by Beaufighter W of 252 Squadron RAF.
Off Orfordness, a Seehund sank the British cable-layer Monarch, 1,150 gross tons.
10 April: Pander + Vogel reported having sunk a tanker of about 1,000 tons. Penzhofer + Schulz attacked a destroyer in the South Falls area. The torpedo failed to release and dragged the submarine to the target, where a collision ensued. The destroyer stood off and machine-gunned the Seehund. The submarine escaped and made Ijmuiden on 12 April.
11 April: East of Dungeness a Seehund attacked convoy UC63B, damaging the freighter Pat Wyndham, 8,580 gross tons. The same day the attacker was sunk by ML 632.
U-5071 (Hullmann + Schiffer) was heading for home when attacked from the air. Splinters damaged the torpedo warhead, which did not explode, and the boat made Ijmuiden on 12 April.
U-5070 (Markworth + Spalleck) discovered a destroyer escorting a refrigerator ship of about 3,000–4,000 gross tons off Dungeness near buoy C6. Markworth fired both torpedoes and dived immediately to 15 metres. After 50 seconds there was a deafening explosion. The Seehund settled on the bottom at 26 metres, screw noises overhead. A four-hour long depth-charge inferno began. U-5070 survived.
At 0828 a Seehund was seen by escort vessel HMS Guillemot three miles off North Foreland Buoy 1. ML 586 gave chase and sank the submarine at 1330 hrs. Later, at 1945, ML 585 sank another Seehund near the South Falls.
12 April: Two Seehund including U-5366 (Hauschel + Hesel) headed for the Thames-Northbound and Thames-Scheldt crossing point. In U-5366 the bilge pump failed, but Hesel carried out repairs under difficult circumstances. On 13 April Hauschel sighted a convoy. Both torpedoes were fired and missed. The boat put into Ijmuiden at 1700 on 18 April.
Between 0758 and 1020, aircraft attacked several Seehund at position 52°N 02°E and claimed one sunk.
At 1630 Mosquito H of 254 Squadron RAF, Wellington V of 524 Squadron and Beaufighters M and U of 236 Squadron attacked and sank a Seehund 25 sea miles west of the Hook of Holland.
13 April: Barracuda L of 810 French Squadron sank a Seehund.
U-5090 (Kunau + Jäger) arrived at Ijmuiden after finding no targets around Dungeness and surviving a day-long depth-charge attack. During the delivery voyages from Wilhelmshaven to Ijmuiden, the boat of Schäfer + Wurster was sunk. The boats had sailed after being informed that 500 RAF bombers had attacked Heligoland in waves.
14 April: Four Seehund including U-5074 (Schöne + Sass) and U-5364 returned to Ijmuiden from unsuccessful sorties.
The losses continued. The destroyer HMS Garth sank a Seehund off Orfordness: on 18 April a land battery at Blankenberghe sank another. A third boat was found beached and abandoned on the 19th. The Konrad + Kaldenberg Seehund which had sailed on 10 April began to founder after being attacked by a fighter-bomber. Konrad was killed. Kaldenberg threw the body of his commander into the sea intending to use it as a float in an attempt to swim for shore. On the way he was found by a British patrol boat and rescued.
At midday on 16 April the tanker Goldshell, part of convoy TAM 40, sank north of Ostend after a violent explosion: it could not be attributed definitely to a Seehund.
While running for Ijmuiden a Seehund ran out of fuel and battery power. After drifting for days the rations came to an end. The current took the boat towards the minefields off Katwijk. On 24 April the crew, having written their farewell messages and put the bottle into the sea, abandoned the submarine. Wehrmacht shore personnel spotted them. Their voyage lasted ten days and is the longest Seehund patrol on record.
On 29 April off Walcheren the steamer Benjamin H Bristow was sunk either by a mine or Seehund torpedo. The last definite torpedoing of a ship by a Seehund occurred on 23 April 1945 near the South Falls. This was the Svere Helmersen. The last Seehund to be lost to enemy action was sunk in a depth-charge attack south-east of Lowestoft on 29 April by the corvette HMS Sheldrake.
Because of the war situation, K-Verband Command cancelled the Seehund training programme on 27 April. Under the protection of the two auxiliaries Frida Horn (Kptlt Hugo Holm), and Meteor, the VP boat VS 517 (Kptlt Paul Masch), the naval trawlers KFK 203 (Lt Otto Klähn) and KFK 204 (Lt Alfired Laon) and a few air-sea rescue boats, the training Seehund were escorted from Neustadt to Eckernföurde and then to Grafensteen in Denmark. The Danes refused to admit them and referred the German convoy back to Neustadt. The training division eventually surrendered at Surendorf.
On 28 April 1945 the Dutch operations terminated, although several Seehund continued to act as blockade breakers into Dunkirk. On 2 May 1945 four boats undertook the dangerous journey and reached the port before the capitulation. On 6 May 1945 the German units in Holland struck their flag. The Royal Canadian Hastings and Prince Edward Regiment of 1st Canadian Division took over Ijmuiden. About 5,000 Wehrmacht personnel went into captivity.
The Seehund pocket U-boats sailed 142 missions from Holland and accounted for about 93,000 gross tons of shipping (British sources estimate 120,000 tons). They were therefore the most successful German midget submarines. These results could not affect the outcome of the war, but if the Seehund had been developed and operational as little as six months earlier, it could have caused Allied shipping grave problems, particularly at the time of the invasion of Normandy. In any case they forced the continuing use of hundreds of escort vessels to protect convoys. The operations led to high losses in personnel and materials. The greatest respect is due to the brave men who accepted the challenge to fight an overwhelmingly superior enemy dominating the sea and air.