This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "O and P-class destroyer" – news ·newspapers ·books ·scholar ·JSTOR(January 2013) (Learn how and when to remove this message)

HMSOribi in 1946
Class overview
Name	O and P class
Operators	Royal Navy  Pakistan Navy  Turkish Navy
Preceded by	L and M class
Succeeded by	Q and R class
Subclasses	4 inch O, 4.7 inch O, P
Completed	16
Lost	4
Retired	12
General characteristics P class[1]
Type	Destroyer
Displacement	1,690tons (1,717tonnes) standard 1,640tons (1,666tonnes) 2,250 tons (2,286 tonnes) full load
Length	345 ft (105 m)o/a
Beam	35 ft (10.7 m)
Draught	9 ft (2.7 m)
Propulsion	2 x Admiralty 3-drumwater-tube boilers,Parsons geared steam turbines, 40,000 shp on 2 shafts
Speed	36.75kt
Range	3,850nmi at 20 kt
Armament	5 ×QF 4 in Mk.V (102 mm L/45), single mounts HA Mk.III 4 ×QF 2 pdr Mk.VIII (40 mm L/39), quad mount Mk.VII Up to 6 xQF 20 mm Oerlikon, single mount P Mk.III 4 (1x4) tubes for21 inch torpedoes Mk.IX 4 × throwers and 2 x racks for 70depth charges
General characteristics (4.7 inch O class)
Displacement	1,610 tons (1,636 tonnes) 2,270 tons (2,306 tonnes) full load
Complement	176 (217 in leader)
Armament	4 ×QF 4.7-inch (120-mm) Mk IX guns, single mounts CP Mk.XVIII 1 ×QF 4 in Mk.V (102 mm L/45), mount HA Mk.III 4 ×QF 2 pdr Mk.VIII (40 mm L/39), quad mount Mk.VII Up to 6 x QF 20 mm Oerlikon, single mount P Mk.III 4 (1x4) tubes for 21 in torpedoes Mk.IX
Notes	Other characteristics as per P class
General characteristics (4 inch O class)
Displacement	1,540 tons (1,564 tonnes) 2,220 tons (2,255 tonnes) full load
Armament	4 ×QF 4 in Mk.V (102 mm L/45), single mount HA Mk.III 4 ×QF 2 pdr Mk.VIII (40 mm L/39), quad mount Mk.VII Up to 6 x QF 20 mm Oerlikon, single mount P Mk.III 8 (2x4) tubes for 21 in torpedoes Mk.IX Up to 60 mines (where fitted-for)
Notes	Other characteristics as per P class

TheO and P class was aclass ofdestroyers of theBritishRoyal Navy. Ordered in 1939, they were the first ships in theWar Emergency Programme, also known as the1st and2nd Emergency Flotilla, respectively. They served asconvoy escorts inWorld War II, and some were subsequently converted to fast second-rateanti-submarine frigates in the 1950s.

The O and P class were based on the hull and machinery of the precedingJ class, but with more sheer forward to counter the poor riding qualities of the Js. These ships used theFuze Keeping Clock HA Fire Control Computer.^[2]

The O-class ships were built in two groups of four. The first group had 4.7 inch guns. They were in low-angle mounts which could elevate to only 40 degrees, and were additionally fitted with a 4-inchanti-aircraft gun in place of one set of torpedo tubes. The second group had 4-inch (102 mm) guns in high-angle mounts and were fitted to act as minelayers; they could be recognized by the flat "beaver tail" stern over which the mines were dropped.

When carrying mines they had to land Y gun, their torpedo tubes and depth charges. The designed anti-aircraft armament was one quadrupleQF 2-pounder "pom pom" and a pair of quadruple0.5-inch Vickers A/A machine guns. The latter proved to be outdated, and were replaced by20 mm Oerlikon guns as they became available, with a total of six single mounts eventually being carried.

The P class were repeats of the O class, armed entirely with 4 inch guns, in high-angle mounts fitted with a new tall design of shield which did not require the ships to lose a set of torpedo tubes to take on further AA guns.

All ships survived the war. Five of them were involved in theBattle of the Barents Sea,Onslow being badly damaged. After the battle, the ships were refitted with tall lattice masts instead of the normal mast.

All of the O-class ships with 4-inch armament were fitted for minelaying.

They served mainly in theMediterranean, where four ships were lost.

• Type 16 frigate: postwar conversion of some O and P class vessels into second-rate fast anti-submarine frigates.

• Destroyers of the Royal Navy, 1893–1981, Maurice Cocker, Ian Allan,ISBN 0-7110-1075-7
• Connell, G. G. (1982).Arctic Destroyers: The 17th Flotilla. London: William Kimber.ISBN 0-7183-0428-4.
• English, John (2001).Obdurate to Daring: British Fleet Destroyers 1941–45. Windsor, UK: World Ship Society.ISBN 978-0-9560769-0-8.
• Friedman, Norman (2006).British Destroyers & Frigates: The Second World War and After. Annapolis, Maryland: Naval Institute Press.ISBN 1-86176-137-6.
• Lenton, H. T. (1998).British & Empire Warships of the Second World War. Annapolis, Maryland: Naval Institute Press.ISBN 1-55750-048-7.
• March, Edgar J. (1966).British Destroyers: A History of Development, 1892–1953; Drawn by Admiralty Permission From Official Records & Returns, Ships' Covers & Building Plans. London: Seeley Service.OCLC 164893555.
• Raven, Alan; Roberts, John (1978).War Built Destroyers O to Z Classes. London: Bivouac Books.ISBN 0-85680-010-4.
• Rohwer, Jürgen (2005).Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Third Revised ed.). Annapolis, Maryland: Naval Institute Press.ISBN 1-59114-119-2.
• Whitley, M. J. (1988).Destroyers of World War Two: An International Encyclopedia. Annapolis, Maryland: Naval Institute Press.ISBN 0-87021-326-1.

Wikimedia Commons has media related toO and P class destroyer.

• Destroyer classes
• O and P-class destroyers
• Ship classes of the Royal Navy

• Articles with short description
• Short description is different from Wikidata
• Articles needing additional references from January 2013
• All articles needing additional references
• Use dmy dates from April 2023
• Use British English from July 2013
• All Wikipedia articles written in British English
• Commons category link is on Wikidata