If you have water in the engines it is going to have to be drained pronto, or it will rust the cranks. Being that it's a big boat as opposed to a pwc they should be equipped with drain plugs, if not pull the plugs, ground the plug wires and crank the thing over until it clears somewhat, start the engines and burn the rest of it out, spray some WD-40 down into the carbs while it's being cranked, that will dispearse the rest of the water.
you need to take it out to the water and run it and burn the rest of the water out.
I know this is an old post, but I just found it again, been out of the loop for while.
first off, fogging oil is to prevent the accumulation of moisture, it doesn't disperse water. WD-40 is "Water Dispersant" hence the name of the formula "WD". you should use fogging oil for strorage of the craft, after the initial treatment of WD-40 and complete removal of water from the engine.
sorry it took so long to reply, computer issues, moving to various locations, etc... lost all my links and contact info..