Re: Bolt on Keel
Bolted-on keels never just fall off. That would randomly contradict the laws of physics.
But like anything else, if they are improperly designed or implemented (as in Hunter's Thursday's Child, or the more recent Bavaria plague) they can fail. If they are improperly maintained by some bozo who uses his bilge as a koi pond, they can fail.
By and large, they just don't fail. Maintaining them is no more of an issue than fixing leaks in the many kinds of encapsulated keels, where any damage to the "capsule" can create a leak that is impossible to fix without hauling the boat and doing extensive glass work. And then, heaven help you if they need to raise that ballast, which probably was put in place before the deck was attached.
I'd suggest that anyone who has a problem with the choice of encapsulated or external ballast, should probably be looking at a multihull, that simply doesn't have one of those damned problematic keel things under it at all.