They missed the window of opportunity for locating the boat, certainly the one for finding it in good condition. That was no more than 48-72 hours. I do understand that it didn't merit the same search as if there had been remaining passengers and don't think they looked very hard. I believe the insurer is more concerned than the authorities were. I think the first two suspicions they had may be reasonable especially chop-shop. It doesn't seem to have any of the characteristics of revenge however. They wanted the boat and what was on it.
How deep was the water near where she was lost? Still traumatized? Say your prayers and move on,, or,, good play. How else do you get rid of a new SLOW boat? It's speculation (Soap Opera) time...