I almost always leave the escorts alone and do repeated runs after sneaking of to reload. I favour firing as many torps at as many targets as I can line up shots for in each run. Between runs I usually sit about 4km off the outer escort just keeping him in view while I dash infront for another run using the time to get the external reserves inboard.
Most runs I've been able to on a single convoy is 4 before running out of eels. I managed to sink 6 ships in that series of attacks over a 12hr gametime period using GW1.1.
