On a close subject...
I've found women crew prefer inflatable PFDs. I asked one time why. The reply was they were more female anatomy "friendly." I carry two inflatable PFDs and, when handing out PFDs prior to sailing, make sure they go to the women onboard first.
As far as the bra question, I'd think a sports bra would be best. Sailing is, after all, a "Sport" ... isn't it? However, as a guy, no bra also works just as well on my boat.
I hadn't thought about an underwire messing with a compass. I guess any metal in clothing with a potential ferous content could do it. Thanks for the tip.
Skipper, J/36 "Zero Tolerance"