Ordered as the Menemsha (AG-39) was built and launched as the Lake Orange by McDougall Duluth Shipbuilding Company, Duluth, Minnesota, in 1918; purchased as John Gehm by the Maritime Commission from her owners, Bison Steamship Corp., Buffalo, New York, in 1941; acquired by the Navy 19 September 1941; renamed Menemsha and classified AG-39 on 15 October 1941; converted from a lake cargo hauler to a weather patrol ship by Maryland Drydock Company.

Averaging about 3 weeks a patrol, she braved the perils of the storm tossed North Atlantic Ocean and the menace of German U-boats to gather valuable weather data from her isolated positions.

As she steamed about midway between the Virginia Capes and the Azores on the moonlit night of 11 August 1943, her lookout spotted a surfaced sub, U-760, about 6,000 yards off her starboard bow.

The determined weather patrol ship fired 20 rounds, one of which struck close aboard the fleeing sub's conning tower.

She rendezvoused with a hunter killer group, headed by USS Croatan, at noon the 12th; however, patrolling aircraft and escorting destroyers failed to flush U-760, who interned herself on the Spanish coast 8 September.