 The German torpedo boats split into five groups , with each attacking a different section of the shipping in the channel . The German 5th Half @-@ Flotilla sailed into the Dover Barrage and soon came into contact with five drifters of the 10th Drifter Division tending the anti @-@ submarine nets and attacked . After hearing gunfire , Flirt — the drifters ′ escort — approached the unidentified vessels and challenged them . The boats responded to the British signal with a similar signal . Confused , Flirt 's commander decided that the approaching vessels were Allied destroyers and that drifters had been attacked by a submarine . An open boat was also launched from Flirt to rescue survivors from the sinking drifters . The German boats attacked the destroyer , surprising the crew and outnumbered , Flirt tried to ram one of the German boats ; after a brief engagement it was sunk by gunfire and torpedoes . After sinking Flirt , the Germans continued the attack on the barrage , sinking two drifters each from the 8th and 16th Drifter Divisions . Six drifters were sunk and three others damaged , as well as the trawler H. E. Straud , before the Fifth Half @-@ Flotilla withdrew . 
