Went to pull my boat out the other day and sunk the back end of my boat with my 80 Merc 2/3's under the water after the trailer sank in some muck. An hour went by before we could get it out so I am wondering would my gas tank vents prevent water from getting in the tank? Its a round chrome vent that sits up about 1/2 an inch with 2 holes in the side. What do you call the stuff that checks for water in gas? Thx for any help.