Phone in a dry bag has proven to be a little too difficult to use as a tactical device so far IME, but... I have been using RaceQs to go back and compare ourselves to other boats that day. Recently also added KattackMobile and am interested to see what it does.

As far as the original question, I've tried several apps and have ended up only keeping one or two b/c they didn't suck as bad as the rest. but it looks like I got suckered into installing a couple of new ones and I don't remember which is which...