The War Emergency Programme destroyers were 112 destroyer

Destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s built for the British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. They were based on the hull and machinery of the earlier J, K and N class destroyer

J, K and N class destroyer

The J, K and N class was a class of 24 destroyers of the Royal Navy launched in 1938. They were a return to a smaller vessel, with a heavier torpedo armament, after the Tribal class that emphasised guns over torpedoes. The ships were built in three flotillas or groups, eight each of ships with...

. Due to supply problems and the persistent failure by the Royal Navy to develop a suitable dual-purpose weapon for destroyers, they were fitted with whatever armament was available. Recent advances in radar and weaponry were incorporated as they came available. As a result they were a relatively heterogeneous class incorporating many wartime advances, but ultimately based on a hull that was too small and with an armament too light to be true first-rate vessels equivalent of their contemporaries. As such they are often described as "utility" destroyers. It was not until the Battle class destroyer

Battle class destroyer

The Battle class were a class of destroyers of the British Royal Navy and Royal Australian Navy . Built in three groups, the first group were ordered under the 1942 naval estimates. A modified second and third group, together with two ships of an extended design were planned for the 1943 and 1944...

 of 1944 that the Royal Navy returned to building larger destroyers. Many vessels were transferred to friendly navies.

Ship Classes

• O class
  O and P class destroyer
  The O and P class was a class of destroyers of the British Royal Navy. Ordered in 1939, they were the first ships in the War Emergency Programme, also known as the 1st and 2nd Emergency Flotilla, respectively...
  
   — "1st Emergency Flotilla"
• P class
  O and P class destroyer
  The O and P class was a class of destroyers of the British Royal Navy. Ordered in 1939, they were the first ships in the War Emergency Programme, also known as the 1st and 2nd Emergency Flotilla, respectively...
  
   — "2nd Emergency Flotilla"
• Q class
  Q and R class destroyer
  The Q and R class was a class of sixteen War Emergency Programme destroyers ordered for the British Royal Navy in 1940 as the 3rd and 4th Emergency Flotilla. They served as convoy escorts during World War II. Three Q class ships were transferred to the Royal Australian Navy upon completion, with...
  
   — "3rd Emergency Flotilla"
• R class
  Q and R class destroyer
  The Q and R class was a class of sixteen War Emergency Programme destroyers ordered for the British Royal Navy in 1940 as the 3rd and 4th Emergency Flotilla. They served as convoy escorts during World War II. Three Q class ships were transferred to the Royal Australian Navy upon completion, with...
  
   — "4th Emergency Flotilla"
• S class
  S and T class destroyer
  The S and T class was a class of sixteen destroyers of the Royal Navy launched in 1942–1943. They were built as two flotillas, known as the 5th and 6th Emergency Flotilla respectively and they served as fleet and convoy escorts in World War II.-Design features:The S class, introduced the CP ...
  
   — "5th Emergency Flotilla"
• T class
  S and T class destroyer
  The S and T class was a class of sixteen destroyers of the Royal Navy launched in 1942–1943. They were built as two flotillas, known as the 5th and 6th Emergency Flotilla respectively and they served as fleet and convoy escorts in World War II.-Design features:The S class, introduced the CP ...
  
   — "6th Emergency Flotilla"
• U class
  U and V class destroyer
  The U and V class was a class of sixteen destroyers of the Royal Navy launched in 1942–1943. They were constructed in two flotillas, each with names beginning with "U-" or "V-"...
  
   — "7th Emergency Flotilla"
• V class
  U and V class destroyer
  The U and V class was a class of sixteen destroyers of the Royal Navy launched in 1942–1943. They were constructed in two flotillas, each with names beginning with "U-" or "V-"...
  
   — "8th Emergency Flotilla"
• W class
  W and Z class destroyer
  The W and Z class was a class of sixteen destroyers of the Royal Navy launched in 1943–1944. They were constructed as two flotillas, with names beginning with "W-" and "Z-", respectively, although, like the preceding U and V class, two of the flotilla leaders were named after historical naval...
  
   — "9th Emergency Flotilla"
• Z class
  W and Z class destroyer
  The W and Z class was a class of sixteen destroyers of the Royal Navy launched in 1943–1944. They were constructed as two flotillas, with names beginning with "W-" and "Z-", respectively, although, like the preceding U and V class, two of the flotilla leaders were named after historical naval...
  
   — "10th Emergency Flotilla"
• Ca- class — "11th Emergency Flotilla"
• Ch- class — "12th Emergency Flotilla"
• Co- class — "13th Emergency Flotilla"
• Cr- class — "14th Emergency Flotilla"

Design changes

• The P, and 3 ships of the O, flotilla were fitted with 4-inch guns with a new design of tall gunshield. As a result they carried only the Rangefinder-Director Mark II(W) for fire control.
• From the Q and R class onwards a transom stern was incorporated.
• From the S and T class onwards the bow was revised to a design based on that of the Tribal class destroyer
  Tribal class destroyer (1936)
  The Tribal class, or Afridi class, were a class of destroyers built for the Royal Navy, Royal Canadian Navy and Royal Australian Navy that saw service in World War II...
  
  , to improve sea-keeping.
• From the Q and R class the main gun calibre returned to 4.7 inches.
• From the R flotilla onwards the officer's accommodation was forwards, instead of aft as was traditional Royal Navy practice
• The S flotilla altered the position of the searchlight between the torpedo tubes with the medium anti-aircraft position abaft the funnel. This more logical arrangement gave the anti-aircraft gun improved arcs of fire in the forward field.
• The S class introduced the new mounting CP Mark XXII for the 4.7-inch guns. This could readily be distinguished from the older mounting CP Mark XVIII of the O, Q and R by its sharply raked face, allowing increased elevation.
• S-class Savage incorporated the new 4.5-inch gun Mark III, in a prototype twin dual-purpose turret BD Mark IV forward and 4.5-inch gun Mark IV in single mountings CP Mark V aft. The former would be introduced in the Battle class destroyer.
• The T flotilla introduced the lattice foremast, to support the ever-increasing weight of masthead electronics.
• The W flotilla introduced the dual-purpose Director Mark III(W), replacing the low-angle Destroyer DCT and High-Angle Rangefinder-Director Mark II(W) in use since the Q and R class.
• The Z flotilla introduced the new dual-purpose Director Mark I Type K and the 4.5-inch gun in single mountings CP Mark V as trialled in Savage. These mountings were based on the CP Mark XXII used in the later 4.7-inch gunned ships; there was no obvious difference.
• The Ch- flotilla introduced the dual-purpose Director Mark VI with full remote-power control (RPC) for gunlaying. As a result one set of torpedo tubes was removed to counter the increased topweight.
• All ships used the Fuze Keeping Clock
  Fuze Keeping Clock
  The Fuze Keeping Clock was a simplified version of the Royal Navy's High Angle Control System analogue fire control computer. It first appeared as the FKC Mk1 in destroyers of the 1938 Tribal class, while later variants were used on sloops, frigates, destroyers, aircraft carriers and several...
  
   High Angle Fire Control Computer.

See also

• Type 15 frigate
  Type 15 frigate
  The Type 15 frigate was a class of British anti-submarine frigates of the Royal Navy. They were conversions based on the hulls of World War II-era destroyers built to the standard War Emergency Programme "utility" design.-History:...
  
  : postwar full conversion of Wartime Emergency Programme destroyers into first-rate fast anti-submarine
  Anti-submarine warfare
  Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....
  
   frigate
  Frigate
  A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...
  
  s
• Type 16 frigate
  Type 16 frigate
  The Type 16 frigates were a class of British anti-submarine frigates of the Royal Navy. They were based on the hulls of World War II-era destroyers that had been rendered obsolete by rapid advances in technology...
  
  : postwar partial conversion of Wartime Emergency Programme destroyers into second-rate fast anti-submarine frigates