Though Operation Substance successfully resupplied Malta in July 1941, the Allies lost planes, ships and men. What followed was the Battle of Valletta, as the Italians try to finish off the convoy while in the Grand Harbor. Paying in kind, sub commander Shrimp Simpson will send 3 subs, HMS Unique, P32 and P33 to Tripoli to wipe out the latest Axis convoy, bound for Rommel. Both sides draw blood and many lives are lost. Learn more about your ad choices. Visit megaphone.fm/adchoices