Bill Kearney wrote:

But something that will affect how the boat actually SAILS when it's
navigating out of the shallows is not just a simple mechanical task.
As others have suggested, it's worth seeking out an actual naval
architect and/or someone that's actually DONE THIS to THAT MODEL boat.

As a naval architect, I would say just go ahead and do it. When you look at
the incredible variety of keel sizes and shapes, you'll realize that it is
actually hard to come up with something that flat out won't work. If you
were racing and obsessing about gaining or losing an eighth of a knot in
identical conditions, it would be one thing. The chance that you won't like
the way the boat sails if you do a modification like this half way
intelligently is finite, but small.

The Sponberg solution linked in the other post is elegant. If the OP's
husband did all the other stuff and can avoid poisoning or burning himself
with the lead, he should be able to do this successfully with not much more
guidance than that and some volume calculations he should be able to manage
with a quick look at a geometry or naval architect text book.

If he just cut the keel off and carried more gear and stores or put the
weight in the bilge, the boat would not be as powerful or fast to windward
but quite possibly not by an amount that he would notice without careful
comparison. There have been many boats offered in two versions with keel
configurations that vary by this amount. I wouldn't recommend this as the
course to take but just to point out that this is hardly as critical an
issue as some responders are maintainng.

Still, it's a big, messy, and dangerous job. I'd focus on that instead of
the results.

--
Roger Long