At 00.51 hours on 29 Jun, 1941, U-103 hit a steamer of 6600 tons with its last torpedo in the engine room that sank by the stern after 21 minutes about 450 miles west of Las Palmas. The ship had been spotted at 16.42 hours the day before and was missed by a stern torpedo at 23.28 hours.
After the sinking, Schütze questioned some survivors but he did not believe them when they told him that they were from the Italian steamer Ernani en route from Las Palmas to Horta, because the course of the ship did not correspond with the mentioned route.

In fact, the U-boat had sunk the Italian blockade-runner Ernani, disguised as the Dutch steam merchant Enggano. Schütze was not blamed for his mistake because he was not informed about the presence of an own vessel in the area.