 "U-735" was anchored in the naval harbour at Horten.When the air raid alarm came at 21.30, "U-735" eventually succeeded in leaving the harbour, having had trouble starting her diesels.At 23.30 NE of Horten she caught the full force of a bomb, sinking just outside the harbour, south of Mølen Island, with 26 men killed and ten missing, including her captain.