I'm not sure this amounts to an analogous incident, but my Westerbeke
82B suffered what sounds like a similar fate a few years back. I purchased the boat in 2007 with only about 600 hrs. on the engine. Put another 600 hrs. on it over the next few years without incident. Had a 1000 hr. service
professionally done before sailing it from Miami
where I had planned to leave it on the hard
over the winter. When I went to have the boat winterized, the engine wouldn't turn over. Turned out that salt water
had infiltrated cylinders 3 & 4, and completely seized #4.
So again -- no inkling of any sort of problem all the way to the dock
. Boat sits on the hard for several months. Engine then found to be seized. WTF??
When there was no alternative but to replace the engine, it turned into a large insurance
claim due to the expense of getting the engine out of the boat, etc., and the most likely cause was ultimately determined to be a design defect in the exhaust system. The ins. co. surveyor
ruled out any snafu with the winterization process, and also ruled out seawater backing up from lengthy engine cranking with the r/w intake seacock left open. Instead, he concluded that a "fine mist" of salt water
had been back siphoning into the engine over a long period of time, and the last trip which involved a lot of motoring -- immediately followed by a lengthy lay-up -- had finally been enough to ruin the engine.
It turns out that when the prior owner had upgraded the original 70hp Westerbeke
with the 80hp one, the dealer who did the install had neglected to also upgrade the exhaust hose with the larger-spec'd ID hose. The muffler itself was also not replaced, and may have been undersized as well. The entire episode was quite a shocker given the engine's low hrs., and considering it had given no warning that anything was wrong until it had completely failed.