worst I've had was about 200km west of Gibraltar, I get a plane spotted! turns out it's one of our Kondor's that's apparently way off course, so it freaked me out it was heading west outbound from Gibraltar as well so i assumed it was hostile, so i crashdived, for a friendly, I did get him to damage a merchie for me by radioing in not 20 minutes later, he turned around and bombed it for me
so if there's a plane or airbase close enough you can make them help you out, same goes for friendly ships, but that's a lot more work and takes a lot longer
Also in the Med near Italy it's easy to get air-support, but you always get more than you bargained for, have seen a bunch of stukas blow up a nice fat passenger liner that I was just about ready to shoot my eels at
Conversely if you sink anything elsewhere in the med it's usually no more than a few minutes before some sort of allied plane shows up, they're very reliable that way
