# War Emergency Programme destroyers

The War Emergency Programme destroyers were destroyers built for the British Royal Navy during World War I and World War II.

## World War I emergency programmes

The 323 destroyers ordered during the First World War belonged to several different classes and were the subject of 14 separate War Programmes between 1914 and 1918. 40 of these were cancelled at the end of the war. The total excludes destroyers building in UK for other navies which were purchased for the Royal Navy following the outbreak of war.
| Programme | Date ordered | Design | No of ships | Notes |
| 1st War Programme | 10 September 1914 | Admiralty M-class design | 16 | Six more had been built under pre-war 1913-14 Programme |
| 1st War Programme | September 1914. | Yarrow M-class design | 4 | Three more had been built under pre-war 1913-14 Programme |
| 2nd War Programme | early November 1914 | Admiralty M-class design | 9 |
| 2nd War Programme | | Yarrow M-class design | 1 | Nerissa |
| 2nd War Programme | | Admiralty L-class design | 2 | Lochinvar and Lassoo |
| 3rd War Programme | late November 1914 | Admiralty M-class design | 22 |
| 4th War Programme | February 1915 | Admiralty M-class design | 16 | including 8 of "Repeat M-class" with raking stems |
| 4th War Programme | | Thornycroft M-class design | 2 | 2 others had been built under pre-war 1913-14 Programme |
| 5th War Programme | May 1915 | Admiralty M-class design | 16 |
| 5th War Programme | | Thornycroft M-class design | 2 | Rapid and Ready |
| 5th War Programme | | Yarrow M-class design | 2 | Relentless and Rival |
| 5th War Programme | | Admiralty R-class design | 2 | Radstock and Raider |
| 6th War Programme | July 1915 | Admiralty R-class design | 17 |
| 6th War Programme | | Thornycroft R-class design | 3 | Rosalind, Radiant and Retriever |
| 6th War Programme | | Yarrow R-class design | 4 | Sabrina, Strongbow, Surprise and Sybille |
| 7th War Programme | December 1915 | Admiralty R-class design | 8 |
| 7th War Programme | | Thornycroft R-class design | 2 | Taurus and Teazer |
| 8th War Programme | 5 March 1916 | Admiralty R-class design | 12 | |
| 8th War Programme | | Yarrow R-class design | 3 | Truculent, Tyrant and Ulleswater |
| 8th War Programme | | Admiralty Modified R-class design | 11 | last 5 actually ordered on 19 April 1916 |
| 9th War Programme | July 1916 | 23 Admiralty V-class design | 23 | Vortigern and Vectis were ordered in August 1916 |
| 9th War Programme | August 1916 | Thornycroft V-class design | 2 | Viceroy and Viscount |
| 10th War Programme | 9 December 1916 | Admiralty W-class design | 19 |
| 10th War Programme | | Thornycroft W-class design | 2 | Wolsey and Woolston |
| 11th War Programme | 9 April 1917 | Admiralty S-class design | 24 |
| 11th War Programme | | Thornycroft S-class design | 2 | Speedy and Tobago |
| 11th War Programme | | Yarrow S-class design | 7 | |
| 12th War Programme | June 1917 | Admiralty S-class design | 33 | 2 of which were cancelled in 1919 |
| 12th War Programme | | Thornycroft S-class design | 3 | Torbay, Toreador and Tourmaline |
| 13th War Programme | January 1918 | Admiralty Modified W-class design | 14 | 7 of which were cancelled in 1919 |
| 13th War Programme | | Thornycroft Modified W-class design | 2 | Wishart and Witch |
| 14th War Programme | April 1918 | Admiralty Modified W-class design | 38 | 31 of which were cancelled in late 1918 or 1919) |

## World War II emergency programme

The 112 destroyers built during the Second World War were based on the hull and machinery of the earlier J-, K- and N-class destroyers of the 1930s. Each of the fourteen flotillas produced consisted of eight destroyers. 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. 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 of 1944 that the Royal Navy returned to building larger destroyers. Many vessels were transferred to friendly navies.
| Class | Flotilla | Date ordered |
| O class | 1st Emergency Flotilla | 3 September 1939 |
| P class | 2nd Emergency Flotilla | 2 October 1939 |
| Q class | 3rd Emergency Flotilla | end March 1940 |
| R class | 4th Emergency Flotilla | early April 1940 |
| S class | 5th Emergency Flotilla | 9 January 1941 |
| T class | 6th Emergency Flotilla | March 1941 |
| U class | 7th Emergency Flotilla | 12 June 1941 |
| V class | 8th Emergency Flotilla | 1 September 1941 |
| W class | 9th Emergency Flotilla | 3 December 1941 |
| Z class | 10th Emergency Flotilla | 12 February 1942 |
| Ca- class | 11th Emergency Flotilla | 16 February 1942 |
| Ch- class | 12th Emergency Flotilla | 24 July 1942 |
| Co- class | 13th Emergency Flotilla | 24 July 1942 |
| Cr- class | 14th Emergency Flotilla | 12 September 1942 |
The 15th Emergency Flotilla, which would have had ships with names starting with Ce, was cancelled in favour of building the Weapon-class destroyers. The two ships being built, Centaur and Celt, became Tomahawk and Sword.

### 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, 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. One set of torpedo tubes was removed to counter the increased topweight.
* All ships used the Fuze Keeping Clock High Angle Fire Control Computer.