In order to commute to offshore oil rigs via helicopter you need to do a training course to learn how to escape a helicopter should it need to be ditched in the water. A large reason for this is that if its ditched it will likely invert as they are top heavy, which makes escape disorienting.

This is one certification: https://en.wikipedia.org/wiki/Helicopter_Underwater_Escape_T...

I've always wondered if folks commuting by helicopter like this have to undergo any sort of training. Given the nature of non-redundant systems in a helicopter it seems like having an emergency plan is prudent. I've never been on a helicopter except to go to an offshore platform though.