Falcon

I recently purchased a Kawasaki xl 1100 , 2002. It has a brand new battery and is in great condition. I recently took it out into the ocean and when I was coming back into the channel going idle speed I noticed the trim gauge was nit working. I tried turning the machine off and then back on. However when I turned it off it lost total power and would not start back up. Totally dead. Connections tight to battery everything inside engine comp looked fine. There was however about and inch of water in the bottom back area.
Any ideas what could be the problem? I even drove the ski home 2 hours with the seat off to air out the engine compartment.