HMS L12 was at sea with an Officer Training Class; at the same time H47 was on independent exercises in the Irish Sea. At 0800 both submarines were off the Pembrokeshire coast with L12 ahead of H47. L12 suddenly altered course to starboard. H47 at once went full astern and to collision stations. The two submarines crashed together with L21 bow penetrating about 2 feet. In only 15 seconds H47 began to sink. L12 also began to take in water but her crew managed to control the flood.
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Boat Classes
Boats In Class
H21 Specification
Length overall
171 ft 9 inch
Beam
15 ft 9 inch
Depth
15 ft 4 inch
Displacement
438 tons (surface)
504 tons (submerged)
Diving Depth
150 ft
Speed
Surface 13 knots (design)
Surface 11.5 knots (service)
Submerged 10 to 10.5 knots (design)
Submerged 9 knots (service)
No. of shafts
2
Armament
4 x 21 inch bow tubes (6 torpedoes carried)
Endurance
Surface: 2000 miles at full power (design)
Surface: 1100 miles at full power or 1600 miles at 10 knots (service)
Submerged: 70 miles at 3 knots (design)
Submerged: 9 miles at 8 knots or 34 miles at 3.5 knots (service)
Complement
22
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This compelling story is the result of many hours spent recording the memories of Fred Henley. His life at sea is at the centre of his being and his own words are at the heart of the book.
At the age of 14 Fred worked on a Thames sailing barge, then after his training at HMS Ganges, he joined his first ship which took him from the icy Arctic Ocean to the heat of West Africa where the Bismarck and her support ships were hunted.