Need help with electrical gremlins

I have a 1999 Nordic Flame with 1999 Merc 502 MPI Mags. The starboard engine has been suddenly dropping out the last two outings. It seems that the engine quits when we hit a wave or any time the boat jolts onto the surface of the water. I am trying to make a list of connections to check and see if there is anything else that I haven't thought of or if any of these are in no possible way the problem. Here's my list so far...

Connections at battery
Connections at battery switch
Connections at starter
Connections at coil and distributer
Connections at ignition kill switch
Connections at ignition key switch
Connections at supply to circuit breaker panel board

Every time this has happened so far, the boat slams...my volts drop, and as the engine dies the oil pressure drops. I really want to get this fixed this week, any other suggestions on what the problem may be would be greatly appreciated.

Thanks