Advantages/Disadvantages of Fin/Shoal

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Ron Mills

What are the advantages/disadvantages of a fin(deep) vs. a shoal in regard to handling,performance,heeling,etc. The question is directed at H34 but I assume is generic.
 
Dec 2, 2003
4,245
- - Seabeck WA
In regards to a H34, let me TEEEELL YOU!

I don't know. :) Mine's deep. Runs great. Never compared her to a shoal keel. We aren't on a lake Ron, so we should have run across one. But then too, our water is deep and shoal draft boats aren't needed here. Seems that logic is all we can go by. The 34 shoal option didn't have a wing keel. Just a shorter and heavier modified fin. That means you're stuck with more weight, all the time. Whether that makes that option more tender, again, don't know. But, I would bet on it. I would also bet that I would kick butt racing one too. The only advantage is skinny water. That's what dingies are for. :) P.S. While we are on the subject, I have a question for all you guys with wing keels. Why? What is the advantage of a wing keel? Sure, one won the Americas Cup, but that was a rule beater. The 12 meter rule had a draft limit. When heeled, the wing, on the Leeward side was lower than the draft would have otherwise been. Prevented leeway too. But for cruising and buoy racing how do you stack up to a fin, (whale tail, bulb or conventional) And if you're in skinny water, doesn't the wing make it near impossible to back off? And what about weeds?Just wondering.
 
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Don Alexander

Shoal Advantage

When you go aground you can usually walk home. Fred, Even the wing keel's designer reckoned a deeper fin keel of the same weight and area would have been superior.
 
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David Robinson

Keels

Deep keels point higher, have less leeway, but draw more water. Winged keels draw less water, the wing theoretically is more efficent when heeled. The combination winged bulbs on Hunters help get you into shallower whater while giving up the least performance. Dave Robinson S/V Quiet Wings
 
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Cliff Ruckstuhl

Deep Draft is King & Australia II not a rule Beater

Ther usually is quite a bit of difference in the shoal verses Deep keel. It is all in the pointing, a deep keel will out point a shoal keel plain and simple all day long. Only advantage or need for a shoal keel is thin water. If this is not a need than the deep keel is the better boat. It will out sail the shoal keel. I disagree that Australia II was a rule beater. It had been measured and approved way before it ever reached New Port. If you get a chance to read the book by John Bertrand called "Born to Win' You would find that the Hull shape was over looked. It alone was a deciding factor in the boats performance. Look at the new inovation's that come out every time ther is a Cup Match. Even all the new IACC boats have a wing keel of some kind or another. Also for the 87 AC Dennis Conner had a Wing Keel that was almost identical to the Australia II boat. The Wing Keel is a good design for a shoal keel, but the wings are nothing but drag for down wind. They allow allot of weight to be added low but the biggest down fall is they are not as efficient of a wing section. They offer shoal draft with a good righting arm. Catalina, Benuateau, Hunter all offer a shoal draft boat. For some the Wing Keel is the only option, for Hunter it is ther shoal keel. If you went to some of the boat shows over the winter and looked under the tarps the Glenn Henderson's new Hunter boats have a very different Wing Keel design. The Winglet's are actually almost in the mid section of the keel compared to the aft end of the keel like on previous designs. All the designs are very different from one another. But over all the deep keel design is the most efficient design for a keel. The 34 deep keel has a 15" deeper keel meaning a lower center of gravity meaning a stiffer boat. They add more ballest to a shoal draft boat trying to off set the center of gravity and get it to where the deep keel boat is. Walking along in our Marina I knew ther was a Shaol Draft and deep draft Hunter 28.5 but not knowing which was which. Just standing on the toe rail it was obvious as to which was which. The shoal rolled and the deep did not. Cliff Hunter 28.5 "Red Dog"
 
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Barrie Mcdonald

Deeper Keel is Definately Better

On the Hunter Legend 37 for example I have the deep blade keel. My neighbour with the same model of boat has the Shoal keel with the large bulb weight. Performance wise there is no comparsion. I out sail him with ease. My boat points much higher and best of all, I don't heel over nearly as much. For example in a 15 knot broad reach I may lean 10 to 12 degrees, my friend in the same wind is way over, 20 degrees plus. Comfort and speed wise. go deep.
 
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Alan

Lets not kid ourselves.....

the wing keels of production sailboats have absolutely nothing in common with AC or any other race boats!!! As already stated, the "wings" simply allow for more weight lower down. Their inherent increase in drag due in no small part to bad design and added wetted surface area make them a very poor choice. If they had been well designed and built that would be a different story. They make a very bad choice for cruising because running aground with a wing is very tough to get off (no pun). I dumped my "wing" for a fin and totally changed the sailing characteristics of my boat. A very big plus in all categories.
 
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Cliff Ruckstuhl

Not really good choice

The Current AC keels are really just a bulb with winglets. Like Alan said there is really no compersion to AC Keel's and current wing keel's. Catalina makes some really bad wing keels in my opnion. I raced against a Catalina 30 wing keeled boat. When we went up wind for him it was over. So giving the choice of a shoal keel or a deep fin ther really is not a choice. Again deep keel is king when it comes to performance. If I decide to move up sometime to a bigger boat like a Hunter 37 that draws 6'6" draft on Lake Erie would only be a problem at the dock. A few marina's that I know of will not accept a boat drawing more than 5 feet. Cliff
 
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Alan

Well I guess I wont...

...be visiting those marinas, Cliff. I draw 6' with the custom keel on my 35.5, but I wouldn't sacrifice my performance for the sake of a marina. I would recommend shoal draft with bulb to cruisers who are worried about depth, but never a wing.
 
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Cliff Ruckstuhl

Thats Lake Erie Sailing

The last few years Lake Erie has gone down in depth. It is part of the cycle lot's of dredging at all the Marina's. It has affected all the Great Lakes. Sailing on the lake's has not been a problem, I draw over 5 feet and know of allot of boats that draw over 6 feet. Just need to pick a deep water marina. I agree I would not trade performance for anything. But draft needs to be taking into consideration. Would be nice if a shoal draft with a bulb was an option but all depends on what your doing with the boat. I need to have a boat that performs well with in my needs. But some do not look for the same as Alan and I. I on a regular basis look at the Tripp 33's for sale loved my Tripp 26 it has the best of both worlds. Deep lifting Bulb Keel. Cliff
 
Dec 5, 2003
92
Hunter 380 Fort Lauderdale
don't plan on going to the Bahamas

At least down here in south Florida you don't have much of a choice but have shoal draft if you want to do the Bahamas or most of the Keys..Not hat it can't be done by playing the tides in some cases or bypassing anchorages etc... For us the shoal draft and the access that comes with it more than outweighed any performance loss.. Brian s/ CREW REST
 
Dec 2, 2003
4,245
- - Seabeck WA
Well, we seem to have something going here

Brian, no argument about south Florida and the Bahamas. An H34 is suppose to draw 5.5 feet. I think Hunter was trying to sell them to south Florida cruisers. No matter how we measure, we get six feet. That's great, I'm not complaining. Cliff, you're right about Australia IIs' wing keel not being a rule beater. That was a poor choice of words on my part. We all know how the AC game is played. They were just playing it better. My point about 12 meter AC boats is that the 12 meter rule limits the debth of the keel, (to what, 5.5 feet? I forget.) The wings tried to get an edge under that rule. that's why DC used it in '87. AC boats were still 12 meters. Well, we seem to agree, production wing keels are not highly thought of,,,,OK, they suck. I'm thinking that folks with center boards would be LOL at this thread. But, lots of disadvatages with those too. That's one of the reasons water ballast was developed. Ah, Winter.
 
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Richard

more bulbs and fins

I must be slightly confused. If simple fins were the best use of water foils then AC boats would not use bulbs with or without wings. For a given cross-sectional area the maximum mass for ballast would be some sort of sphere. Hydrodynamics stretches this into our popular bulbs. My understanding is keels need to provide BOTH lift and a righting moment. A low down bulb is optimal. A shallow bulb....not so good. But there must be some trade-off on keel foil length, otherwise full keel boats would outpoint fins. Oh, my guess is that placing a bulb on the fin bottom reduces vortex shedding,e.g. "drag". So bulbs cannot be that bad. The devil is in the execution. Happy Days
 
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Marcus

Anyone else know a friend who................

....accidentally grounded his boat on a sandbar, only to have the bulb keel start acting more like a Bruce anchor? Ask any BoatUS tow operator what they think. A real keelboat ain't got no anchor attached to the bottom of its keel. Go deep-go fast!
 
Dec 2, 2003
4,245
- - Seabeck WA
Yes Richard

And that is the principal used on whale tail keels. Whales evolved those tails and we finally took note. 'Course, more trade offs, no bulbs, or they wouldn't work. P.S. Too bad we can't drive around in boats with keels a deep as AC boats. If we did, we would only be able to visit deep water ports.
 
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Clyde Lichtenwalner

Another problem with shoal draft

Since you asked, according to Cortland Steck, the designer of the H-34 and many mid-80s Hunters, the H-34 was designed fist and foremost as a shoal draft boat. The hull was optimized for the 4'-3" long fin keel. Can you name any other non-centerboard 34 footer that draws less? They are few. The deep draft keel was designed to fit in the exactly same receiver in the hull, so as you might notice, it is a bit longer at the top of its aft section than appears necessary. The prevailing philosophy of the time at Hunter was that everybody else started with a deep draft and optimized it for race winning performance. The shoal version of the same boat ends up being a poor compromise. For the H-34, 40, 28.5, and 45, all with similar keels, this philosphy was reversed. The shoal version was optimized to perform as well as possible, and then the deep keel was added. That said, H-34 is beamy, as expected in a shoal draft boat, and sails fairly well with the 4'-3" shoal draft keel. But with the deep keel (5'-6" is not really that deep - most 34 fotters of the time had 6' deep keels) the H-34 turns in superior windward performance. Mine passes almost everything its size to weather under the right (<15 knot) conditions. I would be interested in seeing how the shoal H-34 sails against one of the new generation bulb/winglet keel hunters of the same size. Of course, there are lots of other differences, so it might not be a fair comparison. One problem not mentioned, and a big factor to be considered when looking at shoal draft boats, is the draft of the rudder compared to the keel. Spade rudders are vulnerable to damage when grounding. Even the stoutest designs can jam easily, or at worst, break their attachment points and sink the boat. That is one of the main reasons I chose deep draft. The keel is about 1'-3" deeper than the rudder. I am much more likely to ground without damaging the rudder. This vulnerability is the same for most of the wing designs I have seen. In fact, some manufactures have their rudders deeper than the shoal draft keel. That is a major repair waiting to happen.
 
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Stu Sauer

Shoal Draft Performance?

Having sailed aboard and raced on and against shoal and deep draft mid to late 1980's Hunters, I am missing the point of your statement that the 34 was optimized as a shoal draft boat, then a deep keel was developed. Based on my own experience, the shoal draft 34, 31 and 28.5's don't come close to the up wind performance of their deep keeled counterparts. The shoal draft versions have more weather helm, since the longer shallow keel has its center of lateral resistance further aft. There also appears to be a design difference within the '80s Hunter family wherein the deep draft 25.5,31, 34, 37 and 40's have similar trapezoidal shaped keels with a forward sloping trailing edge while only the older style 27 and newer style 28.5 have a vertical trailing edge which promote a more forward center of lateral resistance. I believe that for each model with both shoal and deep draft keels , the leading edges are exactly the same and extend from exactly the same location on the hull. I'm looking thru a 1986 Hunter Owner's Manual which shows all models from 22' to 40'. Obviously, most racers favor the pointing ability of the deep keel models, but racers might also optimize the boat with folding prop, faired keel, rudder and hull and better sails, so an accurate comparison is difficult from deep draft racer to shoal draft cruiser.
 
Dec 2, 2003
4,245
- - Seabeck WA
Stu, give me deep any time

Now as far as who developed what/when, as I recall, BRUCE KING invented the delta keel for Ericson. It was in Sail Magazine. A year or so later, it was on our Hunters. Ericson also came up with the idea of the ice box in the port cockpit locker. It showed up on Hunter at the same time as the keel. One more! The internal grid was invented by King and first appeared on their 36. That was also in the early 80s. I can still quote the ads. Ericson took the high road and hid the grid under and behind the woodwork. They also charged 20K more than Hunter, size for size. I bought a Hunter, Ericson moved production to Mexico and then went out of business. P.S. Clyde, I think the H34 was Cortlands finest work. IMHO. If he was working for Swan, it would still be in production. The depth you list for the shoal keel is the actual measurement of the deep keel, hull to bottom. I get 6' draft with every measure. (good) (and fast) My wife and I had the boat and raced for 2 years before we were in a race that we weren't first to finish. And you noticed those rudders too, scary.
 
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Cliff Ruckstuhl

shoal/deep keel

We have optimized our deep draft 28.5 for racing. UK Tape Drive Sail's Folding prop faired keel and 400 grit wet sanded bottom. I race against a Shoal draft 31 of the same design year's. He has also optimized his boat with the same. When he bought is boat he did not race and the shoal was not a problem. Now that he does race he wishes he had the deep keel. When we race against him he knows he can not point any where close to what we do. So he foots hoping for more speed but only needs to give us 3 seconds a mile. We have a regatta we do that is a wind ward leeward course. He never does this regatta I think because he is not competitive. The shoal keel kills him up wind. (Again this is just what I think) It all comes down to a shoal keel will not point with a deep keel. We could hash it out all day but that is just how it is. I think the shoal will give up at least 5 degree's minium to the deep keel of the same boat. I also think the Hunter boats of the 80's the 28.5,31,34,37 and so on were the finest boats Hunter has produced to date. The are some of the finest boats I have ever sailed on. I think the 33.5,35.5 and the boats with the awful bulb wing keel could be killer race boats if they had gone with a Fin Keel Like Alan has installed. But not just for racing he has taken a great boat to the level it shoud have been coming out of the box to make it a great sailing boat. I true Cruiser/Racer which is what the boats from this design era where. Cliff H 28.5 "Red Dog"
 
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