Brit-
Mount the ZX450.2 high and dry and it will go fine for ya. Mount it on standoffs, in a storage compartment, up high, and away from ballast hoses or other sources of dripping.
If you get it wet mounted with these recommendations in mind, my experience is that you have bigger worries than a wet amp; namely a sinking or sunk boat.
Go for it and have fun!
Phil
Kicker