Events
On This Day - April 10
| 1906 | B8 | Completed |
| 1917 | K17 | Launched |
| 1940 | Thistle (N24) | Lost. In the belief that a German invasion of Norway was imminent Flag Officer Submarines ordered HMS Thistle to Stavanger with orders to sink any enemy vessel that she may spot in the harbour. On 10th April Thistle signaled her intentions in complying with this order and that she had two torpedoes remaining after an unsuccessful attack on a U-boat. With this in mind the Admiralty changed her orders to patrol off Skudenes. No further contact was made with the Thistle. It was later discovered that U4, the U-boat Thistle had previously attacked had, sighted the submarine on the surface and sunk her with torpedoes. |
| 1940 | Tarpon (N17) | Lost. On 5th April 1940 HMS Tarpon left Portsmouth for Rosyth in company with HMS Severn. The following day they were ordered to Norway. On the 10th Tarpon was signaled to take up a new position. Unknown to the Admiralty the submarine had already been lost. Post War German records showed that Tarpon attacked the Q-ship Schiff 40 at 0724: the first torpedo missed as did a second. The Q-ship picked up the Tarpon on her sonar and her periscope was sighted, depth charges were dropped. The counter attack went on most of the morning until finally at 1252 a pattern of depth charges brought wreckage to the surface. The Schiff remained on the scene until 0500 the next morning secure in the knowledge that she had sunk the submarine. |
| 1940 | Sunfish (N81) | HMS Sunfish torpedoes and sinks the German merchant Antares in the Kattegat. Earlier that day, around 1150 hours she missed the German merchant Hanau with a torpedo and around 1520 hours she missed a German auxiliary patrol vessel with two torpedoes. |
| 1940 | Trident (N52) | HMS Trident fires two torpedoes against the German merchant Wandsbek south-south-east of the Oslofjord. Both torpedoes missed. |
| 1940 | Triton (N15) | While operating in the Kattegat HMS Triton torpedoes and sinks the German merchants Friedenau and Wigbert and the auxiliary patrol vessel V 1507/Rau 6. |
| 1942 | Traveller (N48) | Completed |
| 1943 | Safari (P211) | HMS Safari intercepts an Italian convoy and torpedoes and sinks the Italian merchants Loredan, Entella and the Italian tanker Isonzo near Cape Torre delle Stelle off Cagliari, Sardinia, Italy. |
| 1944 | Sunfish (N81) | Transferred to Soviet Navy |
| 1944 | Sunfish (N81) | Transferred to Soviet Navy |
| 1945 | Stygian (P249) | HMS Stygian sinks two Japanese coasters with gunfire in the Java Sea. |
| 1945 | Statesman (P246) | HMS Statesman sinks two Japanese sailing vessels with gunfire in the Strait of Malacca. |
| 1945 | Thorough (P324) | HMS Thorough sinks a Japanese coaster with gunfire of the west coast of Sumatra, Netherlands East Indies. |
| 1963 | USS Thresher | The US submarine USS Thresher sinks off the coast of Cape Cod, Mass., claiming 129 lives |
