If you've had any GOOD results with convoy attacking, please let us know.
Should I perhaps do it with surface ships?
I'm of the opinion that because Convoys are so cheap and fast to build, subs are a wasted diversion of resources for Germany. I'd rather use NAV and older surface ships. It costs less in research and has more versatility (subs are only useful for convoy attacking nowadays).
The caveat to subs being useless is this: Is the UK rebuilding its convoys? If it's not, then even slow attrition will have an impact.
Can anyone speak to that in their games? Does the UK rebuild convoys? Does it escort convoys with the Royal Navy (because this would make it a little safer for the Kriegsmarine to venture forth).