R-class destroyer (1916)

The first R class were a class of 62 destroyers built between 1916 and 1917 for the Royal Navy. They were an improvement, specifically in the area of fuel economy, of the earlier Admiralty M-class destroyer destroyers. The most important difference was that the Admiralty R class had two shafts and geared turbines, compared with the three shafts and direct turbines of the Admiralty M class, but in appearance the R class could be distinguished from its predecessors by having the after 4-inch gun mounted in a bandstand. The Admiralty ordered the first two of this class of ships in May 1915. Another seventeen were ordered in July 1915, a further eight in December 1915, and a final twenty-three in March 1916 (of which eleven were to a slightly modified design).

As well as these fifty ships to the standard 'Admiralty' design, twelve more R class were designed and built by the two specialist builders Yarrow Shipbuilders and John I. Thornycroft & Company to their own separate designs. Three were ordered from Thornycroft and four from Yarrow in July 1915, and two from Thornycroft and three from Yarrow in December 1915.

They were the last three-funnelled destroyers ordered by the Royal Navy (although HMS Bristol (D23) commissioned in 1973 had three funnels, these were not all on the centreline). All of these ships saw extensive service in World War I. Some saw service as minelayers. Eight R-class ships were sunk during the war and all but two of the surviving ships were scrapped in the 1920s and 1930s. One Admiralty R-class vessel, HMS Skate (1917), survived to see service in World War II as a convoy escort, making her the oldest destroyer to see wartime service with the Royal Navy. A second, HMS Radiant (1916) was transferred to the Royal Siamese Navy as Phra Ruang in September 1920.

Ships in class
The ships of this class were ordered under the 5th through 8th War Emergency Programmes through which the government funded the United Kingdom's increased ship production during World War I. The first two prototypes of this class were ordered in May 1915 as part of the 5th War Programme and larger numbers followed, as summarized in the following table:

Admiralty Modified R-class destroyers
The remaining eleven ships ordered in March 1916 were of the Admiralty Modified R class with a slightly increased breadth of 27 ft, a draught of 11 ft, and a tonnage of 1,085. These ships had two funnels.

Thornycroft R-class ships
Only a single R-class destroyer was passed on from the Royal Navy for service in another service:

Yarrow R-class ships
These seven ships built by Yarrow Shipbuilders were sometimes classified as the Yarrow Later M-class destroyer. These ships had two funnels.