At 07.14 hours on 29 May, 1940, U-37 fired three warning shots across the bow of the unescorted Telena (Master Harold Fitch Gosling) off Muros, Cape Finisterre and opened fire with the deck gun when the ship used its radio. Soon her cargo caught fire and the crew was forced to abandon ship which went aground in shallow water. The master and 17 crew members were lost. 18 crew members were picked up by the Spanish trawlers Buena Esperanza and Jose Ignacio de C. and landed at Mari and El Grove near Vigo.

Later the wreck was seized by Spain, salvaged and brought into the harbour of Vigo, where 7400 tons of the oil was salvaged. On 17 Aug, 1940, the tanker arrived in Bilbao and was repaired at the Seatoa Naval Yard. On 7 Oct, 1940, sold to Compañía Española de Petroles, Madrid and renamed Gerona. In May 1975 broken up by Desguaces Cataluna S.A., Barcelona.