One of the less obvious results of the outbreak of the Second World War was a shortage of naval tugs and, to remedy this deficiency, the "Assurance" class was ordered from Cochrane & Sons of Selby (Yorkshire) in 1940. Adept was one of the first to be completed (in 1941) and, like her identical sisters, measured 156½ feet in length with a 35 foot beam and a 16½ foot draught. Registered at 630 tons gross, she was powered by a single screw driven from a 1,350ihp. triple expansion steam engine and could make 13 knots. No information is available concerning her wartime services but her career proved a short one when she ran ground on the south-western side of Paterson's Rock in the Mull of Kintyre, apparently in fog, on 17th March 1942, and became a total loss.