[RustySubmarine]

Sticking to a 256 TC maximum, is about the best option, that's if you are not in too much of a hurry to get to your patrol area. You can set the maximum in SH Commander. I have mine set at 256 Maximum. After patrolling your grid area for 24 hours, move to more lucrative convoy routes. You don't need to stick to the shortest route from your base to the patrol area. Usually if I am allocated a North Atlantic patrol area just south west of Iceland, from my starting base at Lorient or Brest, I usually go through the Irish Sea and round the Northern Ireland coast. The Irish Sea is a haven for convoy traffic in and out of Liverpool or The Clyde Ports. Some convoys come in from the South Atlantic and head for Swansea, Cardiff & Bristol, so the chances of meeting something in these areas are as good as any where. You are the Captain, you decide where you want to patrol, within the limitations of your fuel and that you complete your 24 hours at your allocated patrol grid. Get out and find them, sink them and then come home to reap your rewards, have a bit of shore time before your next patrol. Then do it all again.