The consensus on the Wooden Boat Forum, where one of the people has met the “Master Mariner”, is that this article is complete horse pucky. From what I’ve seen of the structure around the engine in the repowering pictures and gleaned in general, it smells that way to me.
Most older wooden vessels are hogged to some degree. It is a gradual deformation of the entire structure and does not necessarily cause weakness of the kind that would be significant in this event.
WBF brings up another mystery. There was a SPOT Beacon on board which I use consistently and this has an EPIRB function. It is small enough to carry in a pocket. Coverage is pretty good in that part of the world.
They don't appear to have been using the tracking feature which would have narrowed the search area considerably even if they had not gotten off an emergency message. If they were alive and the SPOT beacon was in a pocket, one push of the button and searchers would know where they were to within about 100 feet. It's the first thing that will go in my pocket if I see water over the floorboards.