"P" class Patrol Submarines

Name	Pennant	Builder	Completed	Fate
Parthain	75P	Chatham RDY	13/1/31	Probably mined off Brindisi, c. 31/7/43
Perseus	36P	Vickers	15/4/30	Mined off Zante, 6/12/41
Phoenix	96P	Cammell Laird	3/2/31	Depth-charged by Italian motor boat Albatros off Sicily, 16/7/40
Poseidon	99P	Vickers	5/5/30	Collisionn with merchant Yuta off Wei-Hai-Wei, 9/6/31
Proteus	29P	Vickers	17/6/30	Scrapped 1946
Pandora	42P	Vickers	30/6/30	Bombed by Germany off Sliema, 1/4/42. Salved 1943 & beached, scrapped 1955

These boats were very similar to the "O" classes of boats but slightly larger to accommodate more powerful machinery, and with a raked stem that would become a characteristic of later boats.
Some of the fuel tanks were moved inboard and the long range external tanks were of welded construction to cure the fuel seepage of earlier classes.
Like the "O" classes these boats were designed for the Far East and suffered heavy losses in the confines of the Mediterranean, with only 3 surviving the war.
In 1941 & 1942, Pandora and Parthian were operated as supply ships for Malta. One battery compartment & the spare torpedo compartment were turned over to supply areas, as were some of the crew's and storage areas. Some of the fuel, lubricant, water & ballast tanks were turned over to aviation fuel bunkers. HM s/m's Otus and Regent were similarly altered.
By 1944, Proteus carried one 20mm cannon and three 0.5" MG AA in place of her original AA armament of two 0.303" guns.

Dimensions
Surface Displacement	1760 tons	Length	88.4 m
Submerged Displacement	2040 tons	Beam	9.12 m
Ballast load	280 tons	Draft	4.9 m

Performance & Propulsion
Range	10500 nm, 40 days
Dive	? m
Speed	17.5 kts ( 8.6 kts submerged )
Machinery	2 x Admirality Diesels @ 4640 hp, 2 x Electric motors @ 1635 hp

Armament & Complement
Complement	6 officers & 47 ratings
Armament	Torpedo 6 x 21" bow tubes 2 x 21" stern tubes 14 x 21" torpedoes or; 18 x mines Gun 1 x 1 x 4" DP 2 x 1 x 0.303" MG AA