Patrols / Combat Midnight Rendevous

Just been tucking into this again and got stuck on Midnight Rendevous. From the statistics I've played this mission 73 times now, and everytime the resuply sub dives before I get enough torps to do the job, usually 15 - 17, I've tried stopping everywhere I possibly can, the couple of times I did get enough torps (25 Max), I got buggered by the destroyer escorts so is there a way to stop the coward from diving before I've been fully supplied.

Cheers

Ace

what faction is this mission for, and what mission number, and what edition of ERT are you playing, and what are the mission orders ?