Grampus 1939
| Name | No | Builder | Laid down | Launched | Comp | Fate |
| Grampus | M56 - N56 | Chatham DYd | 8/1934 | 25/2/1936 | 3/1937 | sunk 16/6/1940 |
| Narwhal | M45 - N45 | Vickers-Armstrong, Barrow | 5/1934 | 29/8/1935 | 2/1936 | sunk 30/7/1940 |
| Rorqual | M74 - N74 | Vickers-Armstrong, Barrow | 5/1935 | 21/7/1936 | 2/1937 | BU 3/1946 |
| Cachalot | M83 - N83 | Scotts, Greenock | 5/1936 | 2/12/1937 | 8/1938 | sunk 30/7/1941 |
| Seal | M37 | Chatham DYd | 12/1936 | 27/9/1938 | 5/1939 | captured by Germany 30/5/1940 (UB) |
| P411 | Scotts, Greenock | 1941 | --- | --- | cancelled 9/1941 | |
| P412 | Scotts, Greenock | 1941 | --- | --- | cancelled 9/1941 | |
| P413 | Scotts, Greenock | 1941 | --- | --- | cancelled 9/1941 |
|
Displacement standard, t |
1520 |
|
Displacement normal, t |
1810 / 2157 |
|
Length, m |
89.3 |
|
Breadth, m |
7.77 |
|
Draught, m |
5.13 |
|
No of shafts |
2 |
|
Machinery |
2 Admiralty diesels / 2 electric motors |
|
Power, h. p. |
3300 / 1630 |
|
Max speed, kn |
15.75 / 8.75 |
|
Fuel, t |
diesel oil 119 - 147 |
|
Endurance, nm(kts) |
5880(9.3) / 64(4) |
|
Armament |
6 - 533 TT (bow; 12), 1 x 1 - 102/40 QF Mk XII, 50 M3 mines |
| Sensors | sonar |
|
Complement |
59 |
| Diving depth operational, m | 60 |
Ship project history: Unique British purpose-built minelaying submarines. Porpoise was built under the 1930 program. Design was created on basis of "Ð" class. Saddle-tank submarine had an operational diving depth 60m, maximal depth 95m. Fuel tanks out of a pressure hull were welded. Two horizontal mine tubes placed in a superstructure and extended from an aft end in a bow on about 70m.
After a lead boat 5 more were followed (1932-1935 programs), built on changed design. They had double-hulled construction similar accepted on Thames class fleet submarines. Hull lines which have streamlined at the expense of this decision allowed to raise speed a little at same engine power. Fuel tanks have placed in a pressure hull, the truth, for it was necessary to pay by reduction of fuel stowage.
Already after a beginning of war, under the "War emergency" program it was decided to built 3 more submarines of this class and in January, 1941 even the order has been given out. Soon, however, it have cancelled, as necessity in specialised minelayer has disappeared after working out of the special mines put through TT.
Modernizations: 1940s, Rorqual: can carry 12 M2 mines in TT instead of torpedoes
1942 - 1943, Rorqual: + 1 x 1 - 20/70 Oerlikon
Naval service: One of submarines, Seal, has appeared the unique British ship which has surrendered to the enemy (4/5/1940 was mined in Skagerrak, badly damaged and surrendered to German patrol ships; subsequently she served in German navy as UB; she was scuttled 3/5/1945). Grampus was sunk by DCs of Italian torpedo boats Circe and Clio at coast of Sicily 16/6/1940. Narwhal was sunk by German aircraft at coast of Norway 30/7/1940. Cachalot was sunk by ramming of Italian torpedo boat Generale Achille Papa at Bengasi 30/7/1941.
© Ivan Gogin, 2008-10