Skip Gundlach wrote:

So, we're looking at boats, and Henry Scheel comes to light. He's patented
a keel that several manufacturers are paying royalties to use, and what I
read suggest that rigorous tank testing holds out the superiority to
straight keels, so, presumably, it must be worth *something*...

The Scheel keel is "superior" in the sense that it allows less draft for roughly
similar righting moment and windward performance. If draft is not an issue then
there's no point.


...Now to the question. Have any of you done, or know someone who has, an
addition of such a bulb/wing to an *existing* - not shortened - keel?

Yes, a few.


The
benefits I'd see are better holding, and more ballast, as low as possible,
against a minimal overall increase in weight

"More ballast" isn't a benefit except with respect to greater righting moment,
and there are issues there like the strength of the hull & rig, as Matt has
said. The only vehicle that benefits from added weight is a steamroller.

"Better holding" I think you mean increased hydrodynamic efficiency ie less
leeway. Adding a bulb isn't going to do anything for this. Adding a home-brew
wing keel is not likely to help either, it takes very sophisticated design to
produce a wing that doesn't add more drag than increased lift.



I'm more interested in experience stories, if there are any, or engineering
reasons for or against, as opposed to 'I think it would...' information.

The boats Ive seen this done to were all relatively small, from 19 to 28 feet,
and none showed any improved performance IMHO and all suffered from reduced
reserve bouyancy and were slower in light air.

I have seen a few boats have shoal keels with wings put on to reduce draft, one
was a remarkable success in keeping the same sailing performance and losing 2
feet off the bottom of a 7' keel. But it turned out a good bit more expensive
than the owner thought it would be.

BTW I definitely second (or is it third) the suggestion to ask the people at
Mars Metals.

Fresh Breezes- Doug King