the four ships remained part of the nore and portsmouth flotillas in july 1914, on the eve of the outbreak of the first world war. during the first world war they served with local defence flotillas at the nore and portsmouth, being limited to local defence duties owing to their small size and limited endurance. on 13 october 1914 "tb 116", part of the portsmouth defence flotilla, spotted the german submarine off culver cliff on the east coast of the isle of wight. "tb 116" opened fire on the submarine and attempted to ram, but the submarine dived to safety. "tb 117" was sunk in a collision with a merchant ship, the ss "kamouraska", in the english channel on 10 june 1917. the three remaining ships of the class remained in service with local defence flotillas in december 1918, but by january 1919, only "tb 116" was in service, as a tender at portsmouth. "tb 114" and "tb 115" were sold for scrap in 1919, with "tb 116", which had been used for cadet training, being sold in 1921.