At 07.30 hours on 22 May 1942 the unescorted and unarmed schooner E.P. Theriault was stopped by U-753 with machine gun fire across her bow about 55 miles west of Dry Tortugas. The Germans ordered the crew to abandon ship in a lifeboat and then sent a boarding party of three men aboard to place demolition charges because the deck gun of the U-boat had been disabled in an accident four days earlier. The explosions set the ship on fire and caused her to settle by the bow, but her cargo of pitch pine did not burn well and kept the sailing vessel afloat. The U-boat did not wait for her to sink and left the area. On 27 May, the survivors arrived in Havana and two days later the badly damaged E.P. Theriault drifted ashore in the Bay of Cárdenas, Cuba.

On 3 June 1942 the E.P. Theriault was refloated after her cargo was salvaged. The wreck was sold to Cuba, repaired and returned to service as Ofelia Gancedo for B.P. Gancedo, Havana.