At 21.20 hours on 16 Oct 1942, U-160 fired torpedoes from the starboard side at convoy TRIN-19 50 miles east-northeast of Trinidad. One torpedo struck the Castle Harbour in station #81, which lost her bow and sank within 20 seconds and another struck 30 seconds later the Winona in station #72, which was damaged but reached Port of Spain under own power.

The Winona (Master John Beale Rynbergen) was hit on the starboard side in the #2 hold. The explosion blew the hatch covers off and opened a hole 68 by 28 feet, flooding the #2 holds and causing leaks in #1 and #3 holds. After returning from securing the confidential documents, the master found the helm unattended so he stopped the engines and tried to evade the other ships in convoy, but her bow grazed the stern of the Norwegian steam merchant Austvangen (2420 grt), slightly damaging both ships. The eight officers, 33 crewmen and 15 armed guards did not abandon the badly listing ship, brought the leaks under control by the pumps and steered her into Port of Spain under own power the next day.

On 3 Feb 1943 the Winona left Port of Spain after temporary repairs in convoy TAG-40 to Mobile for repairs and returned to service in April 1943.