| Class overview | |
|---|---|
| Name | Dark class |
| Builders |
|
| Operators | |
| Preceded by | Gay class |
| Succeeded by | Brave class |
| Built | 1954–1958 |
| In commission | 1954–1971 |
| Planned | 35 |
| Completed | 26 |
| Cancelled | 9 |
| Active | 0 |
| Retired | 26 |
| General characteristics | |
| Type | Fast patrol boat |
| Displacement |
|
| Length | 71 ft 8 in (21.84 m) |
| Beam | 19 ft 5 in (5.92 m) |
| Draught | 6 ft 1 in (1.85 m) |
| Propulsion | 2 shafts, Napier Deltic 18 cylinder two-stroke opposed-piston diesels |
| Speed | 40 knots (46 mph; 74 km/h) |
| Complement | 15 |
| Armament |
|
The Dark class, or Admiralty "Type A", were a class of eighteen fast patrol boats that served with the United Kingdom's Royal Navy starting in 1954.[1] All were named with a prefix of 'Dark'. The class could be fitted as either motor gun boats or motor torpedo boats, depending on the type of armament carried. They were the only diesel engined fast patrol boats in the Royal Navy.[2][3] The class was fitted (along with the Nasty class) with the Napier Deltic two-stroke diesel engine.[1] This was of unique layout, an opposed-piston engine with a triangular layout of three banks, 18 cylinders in total.
- ^ a b "Here and There: A 2,500 hp Two-stroke" (PDF). Flight: 392. 2 April 1954. Retrieved 23 December 2009.
POWERING H.M. fast patrol boat Dark Hunter, launched on March 18th, is a Napier Deltic engine. An opposed-piston two-stroke diesel, it develops 2,500 s.h.p.; its power/weight ratio (4.2 lb/h.p.) is said to be the highest ever achieved in a marine diesel.
- ^ Olver, Jeremy. "Dark Class Fast Patrol Boats". Archived from the original on 12 October 2008. Retrieved 9 July 2009.
- ^ "Naval Review Vol.67 No.2 April 1979" (PDF). p. Page 113, Paragraph 2. Archived from the original (PDF) on 25 July 2011. Retrieved 9 July 2009.