 During that time, "U-107" sank 39 Allied ships, in addition to damaging another four ships.The U-boat was launched on 2 July 1940, based at the U-boat port of Lorient, with a crew of 53 under the initial command of Günther Hessler.She was later commanded, in order, by Harald Gelhaus, Valker Simmermacher and her final commander, Karl Heinz Fritz.