At 02.51 hours on 2 Aug 1940, U-99 fired one G7e torpedo at the biggest tanker in convoy OB-191 about 340 miles west of Inishtrahull and hit the Strinda (Master Nicolay Jørgen Dahl) amidships on the port side in the #9 wing tank and bunker oil tank. All power was lost because the explosion had stopped the engines. One of the port lifeboats was destroyed and the crew abandoned ship in the remaining boats. Waiting nearby, the master and some men reboarded the tanker after four hours, brought her on an even keel by shifting the ballast and restarted the engines. The rest of the crew rejoined some time afterwards and the lifeboats were hoisted up at 09.00 hours. The ship returned to port under her own power with two other torpedoed tankers from the same convoy and arrived at Gourock in the evening of 4 August. On 21 October, the Strinda arrived in Cardiff for repairs and returned to service in March 1941.