Do fin keel boats make for decent blue water cruisers or should they only be used for coastal crusing? What advantages do full kell boats have over a fin keel boat?
Full Keel vs. Fin Keel ?
- Thread starter Tai Chi Sailor
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Different strengths
Traditionally, most "blue water" cruisers had full keels while "coastal" cruisers had fin keels. While there are several boats out there cruising offshore with fin keels, they can be a little squirrely in a large following sea. Full keels offer more directional stability but give up windward performance and maneuverability. A compromise is the modified or elongated full keel that many modern cruisers employ, along with a partial or fully skeg-hung rudder. Examples are Bob Perry's Valiant 40, Passport 40, etc. This is a compromise but has worked for many models. Again, you can go offshore in just about any design but boats are designed to excel in certain types of seas and points of sail (along with the associated cargo carrying capacity etc). Hope this helps, Trevor
Traditionally, most "blue water" cruisers had full keels while "coastal" cruisers had fin keels. While there are several boats out there cruising offshore with fin keels, they can be a little squirrely in a large following sea. Full keels offer more directional stability but give up windward performance and maneuverability. A compromise is the modified or elongated full keel that many modern cruisers employ, along with a partial or fully skeg-hung rudder. Examples are Bob Perry's Valiant 40, Passport 40, etc. This is a compromise but has worked for many models. Again, you can go offshore in just about any design but boats are designed to excel in certain types of seas and points of sail (along with the associated cargo carrying capacity etc). Hope this helps, Trevor
a little more detail
Fin keels turn easier. That means that they handle better in tight areas and much harder to go into irons. Full keels, since they are harder to turn, go straight easier which makes it easier (because they tend to want to go straight) on the auto-pilot, especially the mechanical types. I'm not sure why a fin keel points better but I've heard that too as Trevor has said below.
Fin keels turn easier. That means that they handle better in tight areas and much harder to go into irons. Full keels, since they are harder to turn, go straight easier which makes it easier (because they tend to want to go straight) on the auto-pilot, especially the mechanical types. I'm not sure why a fin keel points better but I've heard that too as Trevor has said below.
Fin vs. Full Keel
One of the chief reasons for better performance of a fin keel is that if it is angled correctly the fin keel will yield *lift* (to windward) while on a beat or close reach. Conversely the full keel provides mostly drag and essentially no lift. Directionally, the full keel is more stable at holding course. Full keels usually have *unbalanced* attached rudders, requiring lots of helm pressure (drag) when turned into the slip stream.
One of the chief reasons for better performance of a fin keel is that if it is angled correctly the fin keel will yield *lift* (to windward) while on a beat or close reach. Conversely the full keel provides mostly drag and essentially no lift. Directionally, the full keel is more stable at holding course. Full keels usually have *unbalanced* attached rudders, requiring lots of helm pressure (drag) when turned into the slip stream.
Definition please
What is the difference between a "full" keel and a "fin" keel? Where do "wing" keels fit into the mix and how do they compare with the others?
What is the difference between a "full" keel and a "fin" keel? Where do "wing" keels fit into the mix and how do they compare with the others?
Pointing ability of fins
Having been in a few severe blows with shallows to my lee, I'd have to give a high priority to pointing ability. If I'd of been in full keel boats they'd of been lost. That being said, for an offshore boat, the rudder had better be very well protected.
Having been in a few severe blows with shallows to my lee, I'd have to give a high priority to pointing ability. If I'd of been in full keel boats they'd of been lost. That being said, for an offshore boat, the rudder had better be very well protected.
Wing Keel
I believe a wing keel is just a fin keel with a wing on the bottom. I believe that wing helps give it more control but I would love to hear more about it because that's what I have.
I believe a wing keel is just a fin keel with a wing on the bottom. I believe that wing helps give it more control but I would love to hear more about it because that's what I have.
Hey Tai Chi
There's a lot more to boat design than fin vs. full keel. I've seen some of your postings - they are ambitious and that's great - but if you're planning a major expedition I suggest you do some serious reading before buying a boat. There's a lot of well-informed opinion on this board that can help you, but I'd try and nail down the basics before pulling the trigger on a particular boat. One place you may start is www.sailnet.com - they've got a library of articles on boat design and selection. Good luck to you.
There's a lot more to boat design than fin vs. full keel. I've seen some of your postings - they are ambitious and that's great - but if you're planning a major expedition I suggest you do some serious reading before buying a boat. There's a lot of well-informed opinion on this board that can help you, but I'd try and nail down the basics before pulling the trigger on a particular boat. One place you may start is www.sailnet.com - they've got a library of articles on boat design and selection. Good luck to you.
Franklin, we had a thread on the winged-fin last
summer. The winged keel reached production boats when Australia II won the Americas Cup. The 'rule' at the time, governed 12 meter yachts. The rule for '12s' says that they are limited in keel draft. I recall the maximum depth can't exceed something like five and a half feet. That is the 'straight up'- standing measurement of 12 meter yachts, under the rule. Well, good 'ol Ben Lexen, (sp?) had the idea of 'winglets' on the keel. When these boats heel, the winglet extends the keel deeper and also reduces leeway. It wasn't a new idea but he made it work in competition. The problems that held it back were the usual stuff like DRAG. So, American business, being American business thought, 'lets sell more stuff with this idea'. After all, it won! Americans love a winner. Wing keels appeared on production boats. Are they better than fin keels? We tossed that around here. It was unanimous. NO! They're nothing more than a shoal draft keel with winglets that get stuck in the mud. The worst of both worlds. To go fast, check out Alans' setup. The hot design today copies a very highly evolved mammal. Not surprisingly, it's named the 'whale-tail' keel. Anybody want to form a group and order a bunch of them from Mars?
summer. The winged keel reached production boats when Australia II won the Americas Cup. The 'rule' at the time, governed 12 meter yachts. The rule for '12s' says that they are limited in keel draft. I recall the maximum depth can't exceed something like five and a half feet. That is the 'straight up'- standing measurement of 12 meter yachts, under the rule. Well, good 'ol Ben Lexen, (sp?) had the idea of 'winglets' on the keel. When these boats heel, the winglet extends the keel deeper and also reduces leeway. It wasn't a new idea but he made it work in competition. The problems that held it back were the usual stuff like DRAG. So, American business, being American business thought, 'lets sell more stuff with this idea'. After all, it won! Americans love a winner. Wing keels appeared on production boats. Are they better than fin keels? We tossed that around here. It was unanimous. NO! They're nothing more than a shoal draft keel with winglets that get stuck in the mud. The worst of both worlds. To go fast, check out Alans' setup. The hot design today copies a very highly evolved mammal. Not surprisingly, it's named the 'whale-tail' keel. Anybody want to form a group and order a bunch of them from Mars?
The choices are subjective
Tai, when you do enough reading on this you'll find the choices are not which is "best", but rather how each behaves and what purpose it was made for. The other answers to this string so far haven't filled in all the details about why fin (thin, flat, deep)and full (runs all along the bottom) keels behave differently, and I'm not going to go there, but it's worth hearing some opinions about the choices: I agree with Fred that for a cruiser you want to avoid keels with winglets sticking out (unless your purpose is exploring in shallow waters, when they will help you have a very shallow draft); and I agree with Trevor that longish fin keels look like a nice compromise for coastal cruising that occasionally takes you offshore. People who cruise oceans seem to go for the stability that full keels provide in rough conditions, but most full-keel models are deemed sluggish or unresponsive by coastal cruisers accustomed to fin keel cruiser/racers. And we haven't even talked about swing keels, which were hugely popular at one time and will be found on the market, and bilge keels, those special-purpose beach squatters that are so popular in Britain and so unloved here. On top of all that, if you're buying a used boat you'll find that the marketplace rarely offers you the exact hull/keel/rig/accomodations plan that you're looking for in one boat (that you can afford). There's no right answer, just factors to consider...
Tai, when you do enough reading on this you'll find the choices are not which is "best", but rather how each behaves and what purpose it was made for. The other answers to this string so far haven't filled in all the details about why fin (thin, flat, deep)and full (runs all along the bottom) keels behave differently, and I'm not going to go there, but it's worth hearing some opinions about the choices: I agree with Fred that for a cruiser you want to avoid keels with winglets sticking out (unless your purpose is exploring in shallow waters, when they will help you have a very shallow draft); and I agree with Trevor that longish fin keels look like a nice compromise for coastal cruising that occasionally takes you offshore. People who cruise oceans seem to go for the stability that full keels provide in rough conditions, but most full-keel models are deemed sluggish or unresponsive by coastal cruisers accustomed to fin keel cruiser/racers. And we haven't even talked about swing keels, which were hugely popular at one time and will be found on the market, and bilge keels, those special-purpose beach squatters that are so popular in Britain and so unloved here. On top of all that, if you're buying a used boat you'll find that the marketplace rarely offers you the exact hull/keel/rig/accomodations plan that you're looking for in one boat (that you can afford). There's no right answer, just factors to consider...
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