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post #1 of 25 Old 04-05-2011 Thread Starter
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Changing weight in keel

I could put more lead weights in my keel. I am assuming this would give me a longer water line. I also assume this would be illegal for racing?
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post #2 of 25 Old 04-05-2011
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It might give you a longer waterline.... it will also make the boat heavier, obviously, and created more wetted surface. If you're putting it high in the keel cavity it's debatable how much more righting moment you'd get, and whether that would be advantageous against the increased drag of surface and weight.

Illegal for racing? If PHRF there are mechanisms in place to adjust your rating with the ultimate effects of what you've done in mind. (of course, if you do something like this and don't tell them it would be considered cheating if in fact it helped you on the course)

It's rarely effective to tinker with the original design unless it's a real bad one to start with....

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Last edited by Faster; 04-05-2011 at 11:26 AM.
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post #3 of 25 Old 04-05-2011
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Zzzooms PO had a keel done to change the draft from 5'3" to 7' BUT i sure would not have wanted to pay the bill

We take a 13 second hit for the change

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post #4 of 25 Old 04-06-2011
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Lapworth-

There's a lot we can do to your boat to make it faster before going to such lengths as adding to your ballast.

Better sails, clean the hull, upgrade some hardware...

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post #5 of 25 Old 04-06-2011
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Quote:
Originally Posted by BubbleheadMd View Post
Lapworth-

There's a lot we can do to your boat to make it faster before going to such lengths as adding to your ballast.

Better sails, clean the hull, upgrade some hardware...
New skipper?



Just teasing, lap.


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post #6 of 25 Old 04-06-2011
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When I was younger, it was not uncommon to see yacht designed for lighter air venues add a lead "shoe" to the bottoms of their keels for sailing in windier locales. An example of this is the Thunderbird 26 designed by Ben Seaborne in the early 1950's. T-Birds were designed under a commission from the WPWA (Western Plywood Association) as a means of promoting the use of plywood materials following the end of WWII. The boats were originally designed with sailing in the Seattle area but their ease of construction, speed and versitility made them popular in many areas with much more wind. My first "real" sailboat (ie keelboat) was a 1957 era T-Bird when we lived in San Francisco in the early 1960's. Because the wind was so great, however, the boat was fitted with a 500# lead "shoe" that allowed her to stand up to her canvas better and go like a scalded cat in comparison with her lighter weight sisterships.

Unless you have a very light yacht indeed, the addition of a few hundred pounds to your keel isn't going to have much influence on your waterline. It will however, make the yacht "stiffer" but will also make her motion in a seaway much faster--and in some cases uncomfortably so.

FWIW...

"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."
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post #7 of 25 Old 04-06-2011
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I used to have a Victory 21, a design that came in two versions; one with a bulb on the bottom of the keel, and one without. As I recall, the bulb added about 150 lbs., which was about 10% of the empty weight of the boat. The models with the bulb keel were actually preferred by most Victory owners, as they were considerable stiffer boats, but were a bit more sluggish in calmer conditions.

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post #8 of 25 Old 04-06-2011
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I once owned a well known Canadian built 26 footer. It drew 4' and was rather tender in heavier air and therefore would not go to weather competively.
I built a mold and added 5.5 inches which was 200 pounds of lead and attached it to the bottom of the keel. You could not tell that it had been modified. It made a huge diffrence, the C&C 27 MK1s that were easily beating us before were no longer a challenge and I did not detect any poorer performace down wind.

I raced in MORC at the time (still do actually) and took a modest hit for the modification but it was well worth it.

Last edited by Gary M; 04-06-2011 at 07:34 PM.
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post #9 of 25 Old 04-06-2011
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This is similar to changing design of hull, since added keel weight would significantly change how hull sits in water.

Unlikely to be good idea.
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post #10 of 25 Old 04-06-2011
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The San Juan 7.7 info I was just looking at shows a picture of a shoe .Quote,
"On the east coast in particular, light weight is essential for light air performance,however, the SJ 7.7 as initially design, was simply over powered. The fix was a keel‘shoe’ which was added to the bottom of the keel. The shoe added 4.5" of keel extension and 125 pounds to the weight. The 7.7‘s fixed keel drew four feet without theshoe, approx 4’ 6” with it." http://sanjuan21.net/clark_boat_company_5.pdf
They have a pic of shoe before installation.

Last edited by sidney777; 04-06-2011 at 08:25 PM. Reason: add info
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