I bet that when the impeller went bad and the engine overheated, thats when the head gaskets bit the dust.
Just remember, its just a small "speed bump". Dont let it ruin all of the good times with your family out on the lake forever!

These things happen, its unfortunate-yes, it sucks- yes. But a lesson is always to be learned from these kinds of experiences. That lesson = B.O.A.T. - Bust Out Another Thousand

Trust me, we've all been there, done that when it comes to boating.
Just a little tidbit here. When I bought my 99 Vista 258 this past January the VERY FIRST thing I did along with the obligatory oil change(s) and tune up was replace my impeller. Its something that should be on the list to check/replace annually, IMO.