HMS Terrapin (P323): Brought Home by an American Submarine

The Build: Barrow

HMS Terrapin was built by Vickers-Armstrongs at Barrow, with components supplied by Bellis and Morcom, launched on 31 August 1943 and commissioned on 22 January 1944 under Lieutenant Desmond Samuel Royce Martin, a third-group T-class submarine that would go on to fight hard in two very different theatres.

Third-group T boats were the last and best of the class, built with all-welded pressure hulls instead of riveted ones, and that detail is about to matter a great deal. A welded hull is stronger and more forgiving, and several of her sisters were later cut open and rebuilt because of it, as HMS Truncheon describes. Terrapin was welded too. It was not enough.

From Norway to the Far East

Terrapin's first patrol, off southern Norway in March and April 1944, saw her torpedo and damage the German catapult ship Schwabenland and strike the tanker Wörth near Lista.

The catapult ship deserves more than her name, because Terrapin ended the career of a genuinely famous vessel. Schwabenland was a freighter of 1925, renamed in 1934 and converted by Deutsche Luft Hansa into a catapult ship, a floating airbase that could launch and recover flying boats in mid-ocean for the transatlantic mail.

In December 1938 the German government chartered her for the German Antarctic Expedition. She sailed from Hamburg on the 17th with eighty-two scientists and crew and two Dornier flying boats on her catapults, reached the Antarctic coast a month later, and spent weeks flying aerial surveys over mountains no one had ever seen. The Germans named the region Neuschwabenland, after the ship, and she was home again by February 1939.

Then the Luftwaffe took her over, fitted her with long-range Blohm und Voss reconnaissance flying boats, worked her out of occupied France and moved her to Tromsø in August 1942, from where those aircraft searched for the Arctic convoys. In March 1944 she was in a convoy off Stave in southern Norway when Terrapin put a torpedo into her, and that was the end of her service. A boat commissioned six weeks earlier had finished off the ship that named a quarter of Antarctica.

Redeployed to the Far East that summer, she bombarded the pier at Gunung Sitoli, destroyed coasters, and, working repeatedly alongside HMS Trenchant, sank the Japanese minesweeper W 5, the auxiliary minesweeper Reisui Maru, the submarine chaser Ch-8 and numerous sailing vessels and coasters across the Malacca Strait, one of the more effective operational partnerships of the Far East submarine campaign.

It was, and it is worth knowing what became of the other half of it. HMS Trenchant, the wartime boat of that name, was commanded by Arthur Hezlet, and three weeks after Terrapin was crippled he took her into the Bangka Strait and found the Japanese heavy cruiser Ashigara. On 8 June 1945 he fired a full bow salvo of eight torpedoes at four thousand yards. Five of them hit. It is generally reckoned one of the finest submarine attacks of the war for range and accuracy, and it cost Hezlet a bar to his DSO and the American Legion of Merit.

Ashigara was carrying troops out of Batavia. Most of her crew were picked up; of the sixteen hundred soldiers aboard, only about four hundred were. That is the shape of the war in those waters by the middle of 1945, and HMS Tradewind carries the worst example of it on this site. Terrapin was a thousand miles away in a dockyard by then, being surveyed.

A Devastating Final Patrol

On her seventh patrol in the Java Sea, Terrapin was badly damaged on 19 May 1945 by depth charges from Japanese escort vessels while attacking a tanker under escort, sustaining severe pressure hull damage that forced her to abandon the patrol. She survived only with the assistance of the American submarine USS Cavalla, which escorted her back to Fremantle in Australia.

Six Days on the Surface

Escorted her back does not convey it. The depth charging was on 19 May 1945, west of Batavia. Cavalla found her on 21 May, and what she found was a submarine that could not submerge and could not make full speed. They reached Fremantle on 27 May.

That is the better part of a week on the surface, in daylight, in the Java Sea, in 1945. A submarine that cannot dive is the most helpless warship afloat. She has no armour, almost no anti-aircraft armament worth the name, a top speed slower than most escorts and a silhouette that any pilot in the theatre had been trained to recognise. Every hour of those six days, the entire safety of eighty-odd men rested on nobody happening to look in the right direction. The one thing a submarine does when threatened, she could not do.

What Cavalla could actually offer was not much and was everything. She could not tow her, and a second submarine on the surface doubles the target rather than halving it. What she could do was stay: keep a second set of lookouts on the horizon, be there to take Terrapin's people off if she went down, and make sure that if anything happened somebody would know where and would tell somebody else. There is no tactical justification for it. Cavalla's captain simply did not leave.

And Cavalla was not just any boat. Eleven months earlier, on 19 June 1944, on her first war patrol, she had caught the Japanese fleet carrier Shokaku recovering aircraft during the Battle of the Philippine Sea and fired six torpedoes for three hits, and Shokaku, a veteran of Pearl Harbor and the Coral Sea, blew up and sank. She is still afloat. Cavalla has been a museum ship at Seawolf Park in Galveston, Texas, since January 1971, and anybody can walk through the compartments whose crew spent six days in May 1945 shepherding a broken British submarine across the Java Sea.

The End of Her Story

On inspection at Fremantle, HMS Terrapin was declared a constructive total loss, her pressure hull damage too severe to justify repair, and she was scrapped in June 1946, never sailing operationally again after that final, nearly fatal patrol.

Constructive total loss is an insurance phrase and it means exactly what it says: not that she was destroyed, but that repairing her would cost more than she was worth. The pressure hull is the one part of a submarine that cannot be approximately right. It is a tube designed to be squeezed by tons per square foot, thousands of times, for years, and once it has been distorted by a close explosion nobody can certify that it will keep doing that. Straightening and re-welding a pressure hull is close to building a new one around the old machinery, and by mid-1945 Britain had more submarines than crews.

So she sat at Fremantle, and then she was scrapped in June 1946, aged two and a half. It is worth being clear that this counts as a good outcome. HMS Stonehenge went into the same kind of water and simply never came back, and nobody knows why to this day. Terrapin was hurt badly enough to be written off and did not lose a man doing it, which in the Far East submarine campaign was a considerably better result than most. HMS Thule and HMS Subtle were working the same strait in the same weeks.