On 23 May he spotted a convoy of two tankers. Looking through the periscope he saw that one ship carried French colours, and consulted his identification books to determine her identify. The crew identified the name on her hull—"Damieni". The second ship was called "Alberta". There was no intelligence of neutral shipping in the area and both ships sounded Italian. After some thought, Wanklyn attacked. Three torpedoes were fired and "Capitaine Damiani", a Vichy French vessel travelling under Italian charter, sank by the stern roughly 5 nautical miles (9.3 km) south-west of Punta di Pellaro. "Alberta" carried out evasive action and the escorting vessels dropped 26 depth charges and hunted "Upholder" all afternoon. The following afternoon a further 21 were dropped. None came close. With no Asdic, Wanklyn dived to 150 feet, as he could not easily determine enemy movements. The enemy abandoned the attacks and at dusk "Upholder" surfaced.