the soapy water one would be the one i would do if i didnt have a hole to sink er in, but the hand over the intake, u'd have to have a 1.5in round hole somewhere for the eng to stay running, where are you worried about it leaking? where the snorkle actually go's into the box? i ended up cutting the facotry adhesive and putting on some that i got from home depot. its a rubber type ahdhesive that is ment for plastic and rubber and it is permently plyable. i actually have yet to sink mine:S i need a whench to pull me out haha.
bowz