Join Date: Feb 2000
Location: Annapolis, Md
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performance of sailing boats having a Schelling keel
I assume that you have a Heritage One Ton rather than a Heritage West Indies. Simply loping a foot off of the keel of a Heritage One Ton probably is not an option for a variety of reasons both from a construction and sailing capability standpoint.
The Heritage One Tons were constructed during a period when keel bolts were made as long ''J'' shaped bars that were cast into the lead. Generally these bent bars extended very close to the bottom of the keel so that lopping off a foot of keel will also cut several (if not most) of keel bolts.
Unfortunately there is no easy way to re-establish the structural connection between the keel bolts and lead once the cut has been made. There are ways of roughly mapping the vertical keel bolt positions.
Then there is the whole performance issue. The Heritage One Tonners were high vertical center of gravity IOR era boats. Cutting off a piece of the keel without any other change would make the boats even more tender and more prone to extreme rolling than they already are. It would also greatly change the horizontal position of the apparent center of lateral resistance which would increase weather helm pretty dramatically, which of course would also increase the likelihood of wiping out.
Assuming that the structure was capable of taking the load, a bulb can be bolted to the keel tip to improve stability, but that comes with a high price in performance since the keel spand gets reduced and wetted surface increases, both serious issues with upwind performance.
If you really want to decrease draft on a boat like the Heritage One Ton, then you probably will need to consider a keel swap. In that case you would probably be trading a bulb keel for your current fin. (The discussions that I have seen suggest that roughly 10%- 15% decrease in keel span is cited as being posible for a deep draft fin without increasing the keel root and chord lengths.) Since the Heritage has a comparatively deep canoe body, the keel span is comparatively less than your 7 foot draft and amount of shortening would also be less than your one foot goal.
Increasing the keel root length would require significant changes to the structure of the boat, probably more than would be practical.
Lastly, you are talking about putting a whole lot of money into modifying this boat. While these boats have a pretty strong following, they do not have a whole lot of resale value. The cost of doing the custom keel would be a major proportion of the value of the boat and frankly would probably hurt rather than help resale value in most other sailing venues. (My thinking here is that old race boats that have further had their performance handicapped generally drop in value.)
In any event, should you go either the bolt on bulb or replacememt keel route, I would suggest that you contact Mars Metals, <http://www.marsmetal.com/newpages/keelhome17.html>
who has an excellent reputation for working with owners to produce shallower draft keels.