Events
On This Day - December 23
| 1915 | G 2 (I A4) | Launched |
| 1919 | Thames 1885 - 1920 | Paid off at the Nore |
| 1939 | Undine (N 48) | HMS Undinewas undocked at Blyth. |
| 1940 | Unique (N 95) | Arrived Gibraltar, she was the first U class boat to attack shipping in the Med, albeit unsuccessful. |
| 1941 | U-79 | German submarine U-79 was sunk by HMS Hasty and HMS Hotspur south of Crete. |
| 1941 | Torbay (N 79) | HMS Torbay torpedoes and further damages the Italian destroyer Aviere at Navarino harbour. The Aviere was already grounded. |
| 1941 | Untiring (P 59) | Laid Down |
| 1941 | Varangian (P 61) | Laid Down |
| 1942 | Seraph (P 219) | HMS Seraph tries to ram the Italian submarine Alagi about 40 nautical miles north-east of Bone, Algeria. |
| 1942 | Tally-Ho (P 317) | Launched |
| 1943 | Sportsman (P 229) | HMS Sportsman torpedoes and sinks the Bulgarian troop transport Balkan south of Moudros, Lemnos Island, Greece. |
| 1943 | Strongbow (P 235) | Completed |
| 1944 | Thorough (P 324) | HMS Thorough lays mines in the Strait of Malacca. |
| 1949 | Vigorous (P 74) | Sold for scrapping. |
| 1949 | Ultimatum (P 34) | Sold and subsequently scrapped at Port Glasgow. |
