A survival strategy for a 1945 U-boat captain

What tactics would keep a German U-boat captain alive until the end of the war in 1945?

Patrol cautiously in Arctic waters, hide near or under ice, avoid aircraft and convoys, and engage only when unusually safe.

The proposed survival strategy is to obtain an Arctic patrol area and remain beside a patch of ice. That would reduce the chance of being spotted by searching aircraft and make encounters with convoys less likely. If a convoy did appear, the captain could take a shot and then try to hide beneath the ice. This is a hypothetical avoidance strategy for reaching the end of the war.