[BryceGTX]

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

 

[sea_hunter]

LOL, this argument is always fun. Generally both work as advertised, but full keels rarely fall off.

 

[newbee]

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

 

[sea_hunter]

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.

 

[PCP]

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, Amel….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

 

[sea_hunter]

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.

 

[PCP]

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.

Regards

Paulo

 

[mitiempo]

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.

 

[Faster]

That would be an interesting list..

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

Island Packet and ?????

 

[mitiempo]

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.

 

[mitiempo]

The first large (42') fiberglass cruising sailboat was called Arion. Designed in 1950 by Sidney Herreschoff she had both a fin keel and a spade rudder. She is still sailing. damian mclaughlin corporation - Arethusa

It is not that new an idea and well proven.

 

[ccriders]

utchuckd,
So there; see what I meant when I said "if you can decide in your own head" full vs fin keels?
There really is now way to simplify this decision but to think hard about the kind of sailing you are going to do and where you are likely to do it and then mentally start building the boat of your dreams. Then comes the hard part of finding that boat without having to commission a naval architect.
And then you come to uderstand that saying "every boat is a compromise."
I think very very few people ever got their last boat with their first boat. So don't kill yourself trying to find that perfect boat right out of the box.
Have fun with this journey.
John

 

[killarney_sailor]

Arion is a very pretty boat. I imagine a modern version of that would sell a few copies.

 

[souljour2000]

that's a nice sailboat...thanks for posting MiTiemp...My own boat has an 8 foot beam too...but she's only 29-feet long ! This is interesting...Perhaps alot more 40-foot+ boats would be speedsters like this one if folks didn't have that understandably strong desire for roominess....that canoe stern helps her get out of her own way too though....

 

[Brent Swain]

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.

The single keel on my 36 footer has over 4.6 million pounds of tensile strength in the steel supporting them. Not much chance of that breaking. Keel loses are on high aspect ratio , minimum design racing boats , not on longish fin keels, common on cruising boats.

 

[BryceGTX]

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

If I were you, I would talk to Sabre. The new Sabres show a wing keel for a shoal. Probably a smaller wing though. Not sure about the year of your boat, but the Sabres appear to be a great example of a typical American cruising design. A lot of keel weight, good solid hull.

No doubt anyone can design a bulb keel to create the same righting moment as your existing keel. Unfortuneately, such a keel only adds drag with no hydrodynamic benefit. You will clearly lose some pointing with the bulb. If you want to do something useful with the bulb mass, reshape it to a wing.

My feelings are that a good wing design needs considerable area to gain some hydrodynamic benefit. The benefit to gain is the same or increasing resistance to leway movement with heeling. And possibly some benefit to resistance to vertical moment.

The problems I see with adding a wing to the bottom of an existing shortened keel deals with vertical forces. Movement of the hull vertically creates large forces on the keel-wing joint.

The wing keel is unique in that it can create large resistance to vertical moment. Like a huge rocker stopper. It resists downward movement (same as the hull). And more interestingly enough, it resists upward movement unlike any other keel design.

Again, I would contact Sabre.
Bryce

 

[BryceGTX]

The first large (42') fiberglass cruising sailboat was called Arion. Designed in 1950 by Sidney Herreschoff she had both a fin keel and a spade rudder. She is still sailing.

It is not that new an idea and well proven.

Boy, it is pretty tough to compare this to newer fin keel boats. This boat only has an 8 foot beam and its 40 feet long. And 50% of its mass is in its keel. And its hull is more V shaped than flat. The keel is longitudinally long rather than vertically long like a newer fin keel.

Because its so narrow and v-shaped, this will have a lot in common with the full keel boats. The full keel boats owe much of there sea handling capabilities to the hull design, not necessarily to the keel design.

I think the Valiant is probably very similar. Its hull design is more v-shaped than flat. This contributes immensely to its sea handling.

But you are quite right, the fin design and even the flat hulls have been around for centries.
Bryce

 

[mitiempo]

Fin keel or full keel, a boat doesn't have to be fat.

The Valiant of course isn't quite as narrow as Arion. But after almost 40 years it helps prove a full keel isn't necessary for a boat to be "offshore" capable. There are also many others that have traveled far and wide with fin keels.

I can't think of many full keel boats with high efficiency keels - just large ones with a great deal more wetted surface than necessary.

 

[MarioG]

With in the matter of a year I went from swing keel (Chrysler 22) to fin keel (Chrysler 26) to modifed full keel (Endeavor 32) is my only claim to knowadge.

The swing keel was great for the lake sailing we did and it being our 1st sailboat made learning what running aground meant with the ease of dealing with it. I could see sailing it on the coast in fairer weather. Also great for getting in and out of the water. we stored it on the hard between outtings with mast up.

The fin keel was on our coastal/sound boat that we sailed long weekends on unfamiliar waters. Great for the rougher larger waters but it didn't stop me from thinking how nice if it was also the swing keel version when we ran aground a few times. Fun all around thou I'm never sure the other boats knew we were racing at times.

Now that we are liveaboard cruisiers the modified full keel meets our needs very well.
With the experiance we gained with the other 2 boats, We have been able to cruise the east coast sailing alot on the outside or even sailing the ICW due to its shallow draft. I guess we have learned how to handle it well enough that I have been able to back it out of tight spaces with out much trouble. I know I don't sail as fast as the fin keel boats but I'm in no hurry and it is my home. I don't think I would like it as much if I was only useing it on weekends and I was out to play.

So me being NO expert can only say that it really depends on what type of sailing you do as to what type of keel is better.

 

[barefootnavigator]

This is just my 2 cents and all its worth. I must have missed it but did anyone mention the safety factor of being able to heave to? If you have ever been in a third world boat yard you will appreciate the ease and safety of hauling out a full keel vs a fin keel. A full keel boat can be safely careened for a quickie bottom job, try that with a fin keel. If you haven't seen what happens when a fin keel hits a reef at 6 knots you should come to the Pacific North West and visit any boatyard, its pretty scary. Just a few thoughts