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post #61 of 847 Old 02-29-2012
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Originally Posted by Jeff_H View Post
Wing keels
Wing keels are a specialized type of bulb keel. Instead of a torpedo shaped bulb there are small lead wings more or less perpendicular to the keel. These concentrate weight lower like a bulb and properly designed they also can useful in reducing tip vortex. There has been some discussion that wings increase the effective span of the keel when heeled over but this does not seem to be born out in tank testing of the short wings currently being used in production sailboats. Not all wings are created equal. They potentially offer a lot of advantages, but they are heavily dependent on the quality of the design and I really think that many wing designs are not really working to their potential.
Jeff
Interestingly enough, if we consider the bulb keel to be the oldest design, the wing keel is one of the newer designs. And I tend to agree it has yet to reveal its full potential.

On the other hand, I think Catalina has done a very good job of succeeding in the effective design of the wing keel. The wing is quite big almost as much area as the keel itself. This would appear to actually increase the vertical projection of surface area to lateral movement. Not to mention the change in form with heel angle. The only keel design I know of that has this feature.

Interestingly enough, it is often the racing rules that either directly prohibit or otherwise descriminate (girth measurements) against an effectively designed wing keel. And since racing rules often dictate or influence sailboat design, we find ourselves with sometimes marginal designs for our boats.

This fact has been pointed out for well over 150 years as sailboat designs were even then often compromised by racing regulations. Sadly enough, the bulb design is actually the optimal design to comply with a girth restriction as opposed to an optimal design for a keel.
Bryce

Last edited by BryceGTX; 02-29-2012 at 12:18 AM.
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post #62 of 847 Old 03-05-2012
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Re: Full or fin keel?

LOL, this argument is always fun. Generally both work as advertised, but full keels rarely fall off.
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post #63 of 847 Old 03-06-2012
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Re: Full or fin keel?

Bryce, you said :
Sadly enough, the bulb design is actually the optimal design to comply with a girth restriction as opposed to an optimal design for a keel.

We have been given the opportunity to modify the full keel of a 38 ft Sabre we are in love with to a bulb keel by Mars metal. What would the consequences be? We would be choosing this option because we are very inexperienced sailors looking to learn on our liveaboard. The modification would take 1 1/2 feet off of a 6'6" keel and allow us coastal cruising and maybe a trip south.

Thanks,
newbee
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post #64 of 847 Old 03-06-2012
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Re: Full or fin keel?

Newbee, While there were a number of keel options on the 38, I think a little more research is required. If there's no "real" available information, or even if there is; I think a professional opinion from a naval architect would be in order.
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post #65 of 847 Old 03-06-2012
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Re: Full or fin keel?

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Originally Posted by killarney_sailor View Post
Some responses - based on our experiences
1. I think the bluewater board folks need to get out more. From what we see there are more fin-keeled (think Bob Perry, fairly conservative fins) boats that full-keeled boats (lets say attached rudder types).

...
More important to see what is still out there is to see what are the boat designers (that know more than you or me about boats) are designing now for bluewater cruising boats: Malo, Halberg Rassy, Najad, Moody, Oyster, Tartan, Morris, Amelů.all bluewater boats, all boats that in a distant past used to be full keelers are now fin keelers.

Regarding designs made now (and not old designs that are still made) there are not a single major designer that is proposing a full keeler or any production shipyard that is making one.

Well, not so many years ago a British shipyard had tried that and went bankrupt rapidly.

Regards

Paulo
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post #66 of 847 Old 03-06-2012
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Re: Full or fin keel?

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More important to see what is still out there is to see what are the boat designers (that know more than you or me about boats) are designing now for bluewater cruising boats: Malo, Halberg Rassy, Najad, Moody, Oyster, Tartan, Morris, Amel….all bluewater boats, all boats that in a distant past used to be full keelers are now fin keelers.
Fin Keels have nothing to do with seaworthiness; they're about speed/production costs = profits. Do a "loses keel" on Google. Check out the images too.
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post #67 of 847 Old 03-06-2012
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Re: Full or fin keel?

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Originally Posted by sea_hunter View Post
Fin Keels have nothing to do with seaworthiness; they're about speed/production costs = profits. Do a "loses keel" on Google. Check out the images too.
You seem to have a trauma with losing the keel. Do you know how many Benetaus were produced? Well, they make between 1000 and 2000 a year, make a guess!

Do you know how many keels where lost? I never heard about a single one


If you make radical very low weight racers the chances are that if something goes wrong on the construction or the architect calculations are too optimistic, they may have problems with the keel. But anyway on those boats keels should be checked regularly and they are not designed for bluewater cruising.

I have given you an example with Benetau and that is not a boat designed specifically with bluewater cruising on mind. Now regarding those bluewater boats that I was talking about : Malo, Halberg Rassy, Najad, Moody, Oyster, Tartan, Morris, Amel, do you ever heard about any problem with a keel?

So why a fin keel if properly designed and produced is lesser safer or make a boat less seaworthy? Fin keels are more efficient and they do the job better than full keels and that’s why NA are not using full keels anymore.

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post #68 of 847 Old 03-06-2012
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Re: Full or fin keel?

I agree with Paulo.

Of all the sailboats sailing today I would guess about 80 to 90% are fin keel boats. The full keel boats like the Albergs, Cape Dory, etc are a very small percentage and very few full keel boats are produced today.

Very few have ever lost their keel.

They have everything to do with seaworthiness. A boat that sails efficiently and is easy to maneuver is always a better choice.

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post #69 of 847 Old 03-06-2012
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Re: Full or fin keel?

That would be an interesting list..

What manufacturers currently producing boats still build 'full keel' boats?

Island Packet and ?????

Ron

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post #70 of 847 Old 03-06-2012
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Re: Full or fin keel?

Cape George is one I can think of, for those wanting a modern (fiberglass) version of a 50 year old Atkins design. There are a few others, but not many.

Early fiberglass boats were essentially copies of the wooden boats that preceded them. A plank on frame boat is not as structurally able to carry a fin keel and most had full keels with the ballast attached to the deadwood.
Modern construction allowed design to change and allowed fin keels to be produced that were stronger than the full keel wooden boats of the past.

The Valiant 40 is a good example of a fin keel boat that has proven itself over the last 39 years.
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