You'd have to be pretty unlucky to have the keel fall off. It's bolted very nicely into steel
plates that are then welded to transverse steel
stringers that bolt onto the wooden ones. It's also encapsulated in fibreglass and glassed into the hull
. You could remove all of the keel bolts
and it would probably still not go anywhere. However, if you're worried about keel bolt corrosion
(galvanic or otherwise) take a good look at the keel bolts by backing off the nuts one at a time. You can do this in the water
. Just back off one nut so you can see the bolt properly where it comes through the bottom of the boat. If it's good, tighten it back up again and move on to the next one.
One of the problem i did have was with mast
. It's a problem that other WI36 owners have also reported (i think you have the same boat yes?). The aluminium mast
sits on an aluminium plate which is then bolted onto a mild steel I-beam using stainless bolts. The aluminium mast step plate can corrode very quickly indeed, but in my case thankfully took the brunt of the damage before i fixed it permanently.
Sounds to me like your friend had a serious electrical
leak perhaps, and had wired each of his through-hulls into the negative ground? Whatever the cause, what you've described is very rare, especially in such a short period of time.