# Dark-class patrol boat

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. 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. The class was fitted (along with the Nasty class) with the Napier Deltic two-stroke diesel engine. This was of unique layout, an opposed-piston engine with a triangular layout of three banks, 18 cylinders in total.

## Construction

The boats were constructed with alloy framing and wooden decks and skin. The exception was Dark Scout which had all aluminium decks, skins and frames. Originally 27 units were ordered by the admiralty from seven builders. Nine were eventually cancelled in 1955, including Dark Horseman which at the time was partially completed and on the stocks in the builders yard.
The all-aluminium version was exported to Burma (five units), Finland (two units), and Japan (one unit) by builders Saunders-Roe.

## Design

With no previous experience of using diesel engines in vessels of this size, it was not fully understood how dirty they would get from the exhaust fumes. Originally launched in the normal Royal Navy grey, they eventually had their hulls painted completely black to disguise the staining from exhaust emissions . For a short while, a compromise half grey/half black combination was used.

## Fate

An Admiralty decision in 1957 took nearly all fast patrol boats out of commission, with nine of the new Dark-class to be laid up. On 20 December 1960, the Admiralty stated that the Coastal Forces would not be completely abandoned in case it needed to be expanded in the future. A special boat squadron was nominated, but it did not include any of the Dark-class.
Several of the ships were sold to Wessex Power Units for sale onto the Italian Customs Service (8 hulls) in February 1966. Two were used for target practice, with Dark Gladiator sunk by HMS Amazon and HMS Naiad off Portland in December 1975. At least two, Dark Clipper and Dark Fighter, managed to survive up to as recently as June 2001 when they were broken up in Malta.

## Legacy

The Dark class would be the final commission of this quantity for patrol boats of this size and speed. The following classes had greatly reduced numbers with the Brave class numbering only two vessels and Scimitar class numbering only three.
A similar hull design was used by Saunders-Roe in a prototype, R-103, which led to the development of the experimental hydrofoil, HMCS Bras d'Or, for the Royal Canadian Navy.

## Ships

| Operator | Name | Pennant | Builder | Launched | Fate |
| Royal Navy | Dark Adventurer | P1101 | Saunders-Roe | 28 October 1954 | Sold January 1970 |
| Royal Navy | Dark Aggressor | P1102 | Saunders-Roe | 9 December 1954 | Sold on 3 October 1961 |
| Royal Navy | Dark Antagonist | P1103 | Saunders-Roe | 11 December 1954 | Sold February 1966 |
| Royal Navy | Dark Avenger | P1105 | Saunders-Roe | 6 September 1955 | Sold February 1966 |
| Royal Navy | Dark Biter | P1104 | Saunders-Roe | 23 June 1955 | Sold February 1966 |
| Royal Navy | Dark Buccaneer | P1108 | Vosper & Company | 30 September 1954 | Sold February 1966 |
| Royal Navy | Dark Clipper | P1109 | Vosper & Company | 9 February 1955 | Sold on 16 March 1967 Broken up June 2001 |
| Royal Navy | Dark Fighter | P1113 | Taylor (Chertsey) | 4 October 1955 | Sold on 16 March 1967 Broken up June 2001 |
| Royal Navy | Dark Gladiator | P1114 | Taylor (Chertsey) | 5 December 1956 | Used as target and sunk December 1975 |
| Royal Navy | Dark Hero | P1115 | McGruer (Clynder) | 16 March 1957 | Used as target 1977 Sold 1985 |
| Royal Navy | Dark Highwayman | P1110 | Vosper & Company | 29 March 1955 | Sold on 16 March 1967 |
| Royal Navy | Dark Hunter | P1116 | Miller (St. Monance) | 18 March 1954 | Sold on 13 April 1962 |
| Royal Navy | Dark Hussar | P1112 | Thornycroft | 16 May 1957 | Sold February 1966 |
| Royal Navy | Dark Intruder | P1118 | Morgan Giles (Teignmouth) | 6 July 1955 | Sold February 1966 |
| Royal Navy | Dark Invader | P1119 | Morgan Giles (Teignmouth) | 6 September 1955 | Sold February 1966 |
| Royal Navy | Dark Killer | P1111 | Thornycroft | 26 September 1956 | Sold February 1966 |
| Royal Navy | Dark Rover | P1107 | Vosper & Company | 30 August 1954 | Sold February 1966 |
| Royal Navy | Dark Scout | P1116 | Saunders-Roe | 20 March 1958 | Sold on 2 July 1961 |
| Myanmar Navy | | T201 | Saunders-Roe | 24 March 1956 | Stricken 1975 |
| Myanmar Navy | | T202 | Saunders-Roe | | Stricken 1975 |
| Myanmar Navy | | T203 | Saunders-Roe | | Stricken 1975 |
| Myanmar Navy | | T204 | Saunders-Roe | | Stricken 1975 |
| Myanmar Navy | | T205 | Saunders-Roe | | Stricken 1975 |
| Finnish Navy | Vasama I | | Saunders-Roe | | Stricken 1977 |
| Finnish Navy | Vasama II | | Saunders-Roe | | Stricken 1979 |
| Japan Maritime Self-Defense Force | | PT9 | Saunders-Roe | | Stricken 1972 |

### Cancelled ships

| Operator | Name | Builder |
| Royal Navy | HMS Dark Attacker | Saunders-Roe |
| Royal Navy | HMS Dark Battler | Saunders-Roe |
| Royal Navy | HMS Dark Bowman | Saunders-Roe |
| Royal Navy | HMS Dark Chaser | Vosper & Company |
| Royal Navy | HMS Dark Chieftain | Vosper & Company |
| Royal Navy | HMS Dark Crusader | Vosper & Company |
| Royal Navy | HMS Dark Defender | Thornycroft |
| Royal Navy | HMS Dark Explorer | Thornycroft |
| Royal Navy | HMS Dark Horseman | McGruer (Clynder) |