My best evasion is to go
deep and make some bets with my crew. If I loose, no problem, if I win, all their money earned in that patrol is mine.
Next trick I started to use recently is to attack when surfaced in heavy rain or fog that we all have plenty of them. Evading in such weather is a piece of cake - you just sail away and wait for your torpedoes to be reloaded. Risky, yes, but it's really not as hard as it could seem to be.