Pete, this sucks bro... I feel for ya! At least it happened at the end of the season and by the sounds of it you had a great riding season.
Its kinda hard to give an exact guarantee of whathuge cause was since you know you had multiple issues. There's no doubt the crank bearings were bad and thats what the large pits are in your piston and head dome. I agree with Nuclear on most of his statements I also notice the head has 1 black dome with carbon buildup (normally indicates a lean condition) and the rod is bent (could have been from hydrolocking or could have bent just from the lower rod bearing coming apart and breaking the rod). I do think this may have had a lean condition with possible detonating because the piston looks very chalky from heat and deto as well as the head dome that's black (shiny dome stays shiny from fuel or water wash down). There's a lot of variables since there was water ingestion with hydrolocking, timing jumping all over, and a high hour stroker crank all in salt water. I think the high hour crank with water ingestion brought the bearings to it's final hours of service life. The sporadic timing likely caused detonation and the hydrolocking may have caused a bent rod which would throw the engine off balance and possibly even causing a weak crank seal to leak and lean out that immediate cylinder. I don't have a fully detailed scenario of how everything went down any this is just my thought, could have gone down differently but I think that crank was already weak and the water ingestion/hydrolocking caused permanent damage and the engine only ran for a few hours before these characteristics caused a full engine failure.
Pete, on a side note I will buy the cylinder if you sell it. Your last post said you would put a new engine in there...
And I'll buy the Thrust trim
