Hello Fabrizio,

The Malta records are not very detailed but the closest account appears to be the tug EMILY on inshore patrol which opened fire on a submarine. This said, the Malta war diaries record the action on 14 July but I would not be surprised given their sketchiness that the date recorded is in error.
There is also records of an attack by the A/S trawlers CORAL and JADE in July but the attack was with depth-charges and CAPPONI does no report being depth-charged.

Best regards,

Platon