Quick and dirty: Before splitting the ships, send out one full salvo of torpedoes from each ship. Send one ship East and one ship South-West (to avoid the patrolling ships). It comes down to timing, but the ship sent directly to the east should haul ass and fire at any cargo ships in sight. Depending on where you park and what direction you're facing it is possible to hit as many as five ships without moving.
The ship sent to the south should wait until the patrol has fully entered the cove before approaching. Once again, have it swing North and fire at all parked ships. By this time the patrol should be taking out the first ship, so it won't be focused on you. By slightly entering the cove where the Southern-most ship is docked you can take out the rest of the ships without moving.
Originally Posted by demi
It's all luck and nothing but. There is no skill in Pinball.