Events
On This Day - August 20
| 1906 | C 5 (I 35) | Launched |
| 1906 | C 6 (I 36) | Launched |
| 1917 | E 47 | Lost for reasons unknown. |
| 1919 | L 54 | Launched |
| 1934 | Grampus (N 56) | Laid Down |
| 1940 | Cachalot (N 84) | Torpedoed and sunk U-51 in the Bay of Biscay west of Nantes, France. |
| 1940 | Undaunted (N 55) | Launched |
| 1941 | Thrasher (N 37) | HMS Thrasher sinks the Greek sailing vessel San Stefano with gunfire off Cape Malea, Greece. |
| 1941 | Unique (N 95) | HMS Unique torpedoes and sinks the Italian troop tansport Esperia 11 nautical miles off the Tripoli lighthouse, Libya. Consequently attacked by aircraft and damaged resulting in her return to Malta. |
| 1941 | Upholder (N 99) | HMS Upholder torpedoes and sinks the Italian merchant Enotria 5 nautical miles off Cape San Vito, Italy. |
| 1943 | O 24 (Dutch) | Torpedoed and sank the Japanese auxiliary gunboat Chosa Maru 8 nautical miles southwest of Penang, Malaya. The Chosa Maru had left Penang a few hours before when the Japanese heard of the attack on the German Quito the day before. |
| 1944 | Satyr (P 214) | HMS Satyr fires four torpedoes against the German merchants Bochum and Emma Sauber off Skudesnes, Norway. All torpedoes missed their targets. |
| 1962 | Otter (S 15) | Commissioned |
| 2015 | Artful (S 121) | Arrived at Faslane for the first time |
