File:HMS Tobago (1918) Model.jpg

English: Contemporary builder’s model of the S Class destroyer HMS Tobago at the Science Museum, South Kensington, 15 November 2008.

The standard RN destroyers built during WWI were the M, R and Modified R classes, both to Admiralty and builders’ designs. Towards the end of the war it was thought Germany were building some larger, more heavily armed destroyers and the Admiralty’s response was to build the highly successful V&W Class of 1917-18 and Modified W Class of 1919-23.

In the event, the large German destroyers never materialised (except for a couple at the very end of the war) and the V&W’s were too expensive to build in the large numbers required by the RN. Thus it was decided to build an updated Modified R Class, which could be built more quickly and more cheaply than the V&W’s. The result was the S class, 67 ships being built in 1918-24 in 3 versions: 55 Admiralty designed ships completed in 1918-24, 5 Thornycroft designed ships completed in 1918 and 7 Yarrow designed ships built in 1918-19. Most saw service in the last stages of WWI and were very highly regarded.

HMS Tobago was one of the 5 Thornycroft-designed S Class ships launched and completed at the Woolston yard, Southampton in 1918, which had 29,000 shp turbines, had a designed maximum speed of 36 kts (though often reached 38 kts on trials), measured 267 ft x 27.3 ft x 9 ft and had a displacement of 1,087 tons. They were armed with 3x4”, 1 x 2 pdr AA guns and 4x21”TT (in two twin sets on turntables) and, on the first few only, 2x14” TT singles (soon removed as useless). The Tobago was mined in the Black Sea in 1920 and so badly damaged that she was scrapped in 1922.

After the end of WWI it looked as if the S Class would remain in RN service or in reserve for a long time. However, the London Navy Treaty of 1930 led to the decision to scrap most of the 58 survivors which would have been found very useful in WWII. Nonetheless, on the expiry of the Treaty in 1936 there were still 20 survivors and the international situation suggested that they would soon be needed. However, on looking at those in reserve it was found that they hadn’t been mothballed correctly and had suffered severe corrosion; 9 had to be scrapped in 1937-38 but 11 (all Admiralty type) survived (as did 1 R) to fight in WWII (5 being lost), most modified to serve as A/S escort vessels. The survivors were scrapped in 1945-48. The S Class were one of the RN’s most successful destroyer classes.