the hand-protectors like on new wipi or all slinger bars make it float.
but if you ride with a snap shackle, it is not very important, i think - i don't know if my airush bar floats - because i never came into the situation
as far as i know, the naish arx bar does not float, but the cabrinha sinks like a stone ...
the 'floaters' are very good for short bars - i've seen situations, where the leader lines could have hurt rider's hands but with this protection, nothing happened.