I think a helmet cam could work. When you have the camera on, you just restrict your head movement and/or edit out the parts where you need to look around. But on a distance race a helmet cam could work. I could see it getting in the way on a buoy race, plus you are looking around a lot more. We'll keep the thing tucked away after the start, when we are likely to be looking around where to go. But once we've "made our bed", so to speak, and with long tacks, some opportunities might arise.
Also, the crew can hold it (provided the seas aren't too nasty).
I can imagine, though, no one is going to want to look at video unless it is blowing at least 15k...unless it involves bikinis (and, no, I ain't wearin' no bikini!!!).
Good point about the batteries. We are already bringing a ton for the toys (compass, GPS, VHF, etc.).