| Build Group: | H21 |
| Fate: | Cancelled |
| 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 |
Early in 1915 an experiment took place in the Firth of Forth of a C class boat being towed submerged by a powerful tug. The submarine was towed along at various depths, using a towing slip to enable her, at the opportune moment, to release herself and so make the attack. It was C27 which carried out these experiments which proved quite a success, she and C19 were sent to Aberdeen for actual operations.
An account of the development and use of the human torpedoes, semi-submersible and midget submarines mainly in WW2 but including some of the developments that took place in 1918, with many half tone photo ills. and brief accounts of many of the actions involving these craft
12 pages added or updated in the last 2 month
Please help to maintain this site by reporting any Errors, Broken Links, Information or Site Issues on this page using this button
If you find this site useful, please consider supporting my work with a small Donation.
Please Note: Donations made using this option go directly to the site owner and not to the Submariners Association.
Thankyou for your support.
| 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 |
Early in 1915 an experiment took place in the Firth of Forth of a C class boat being towed submerged by a powerful tug. The submarine was towed along at various depths, using a towing slip to enable her, at the opportune moment, to release herself and so make the attack. It was C27 which carried out these experiments which proved quite a success, she and C19 were sent to Aberdeen for actual operations.
An account of the development and use of the human torpedoes, semi-submersible and midget submarines mainly in WW2 but including some of the developments that took place in 1918, with many half tone photo ills. and brief accounts of many of the actions involving these craft
12 pages added or updated in the last 2 month
Please help to maintain this site by reporting any Errors, Broken Links, Information or Site Issues on this page using this button
If you find this site useful, please consider supporting my work with a small Donation.
Please Note: Donations made using this option go directly to the site owner and not to the Submariners Association.
Thankyou for your support.

This form is for you to comment on, or add additional information to this page. Any questions will be deleted. If you wish to ask a question contact the Branch or the Webmaster using the Contact Us page or ask your question on our Facebook Page