NormanS
Well-Known Member
A little bit of water goes a long way inside a shallow fin-keeled hull, whereas with a long keel, you normally have a deep bilge. This might be significant depending on what type of shaft seal you have.
Considering a long keel...
- Thread starter MASH
- Start date
King Penguin
Well-Known Member
It's downwind in blustery conditions I notice the difference the most, my Rasmus tracks straight and true and makes passages when on my last fin keeler I'd be wrestling with the helm so much more relaxing and comfortable.
True, she is not as manoeuvrable in marinas but after a year or two of ownership I got the hang of it and I can now tuck her in most places now. She will turn in her own length (almost) as long as there is no weigh on her before you turn her.......it was a revelatory moment when I discovered this!
True, she is not as manoeuvrable in marinas but after a year or two of ownership I got the hang of it and I can now tuck her in most places now. She will turn in her own length (almost) as long as there is no weigh on her before you turn her.......it was a revelatory moment when I discovered this!
wotayottie
Well-Known Member
Its inevitable when you have lots of posters on here who are elderly and fixed in their traditional views. Its also the case that any boat, however much of a dog it is, will have someone on here who loves it dearly and will speak up for it. Sailors are romantics after all.
Just think - you get enthusiasts on here for Seagull outboards, something with the technology of a 1930s motorcycle. There are small numbers still going for things like dead eyes, and gaff rig. And for old style wooden hulls - a method of construction that had its heyday in the 1890s when there wasnt any real alternative. . And that era is of course where the long keel comes from . Its a keel shape and hull design which fits well with timber construction and the limitations this in its traditional form puts on shapes.
We know a great deal more nowadays about foil shape and hydrodynamics, one reason why no mass manufacturer feels the need to offer long keel boats. Avocet lists what he sees as the advantages of a long keel and some of them I can agree with - after all, even a Seagull o/b has some plusses. Most point are not in my view linked to a long keel shape.
So 1 is correct - a long keel will give greater directional stability or on the other side of the coin worse ability to turn and tack. 2& 3 are nothing to do with a long keel and 4 is only connected to encapsulated keels or to people who worry. 5 isnt related to keel length but 6 is correct if the rudder is attached to the keel - it isnt on all long keels like the Vancouver for example. 8 could be a long keel benefit if the long keel is nice and level. 7 and 9 are all about hull design as well as keel shape. But I reckon he has missed out the biggest single advantage , the way in which a long keel resists being blown sideways at low speed when the deep fin loses effectiveness.
As for disadvantages 1,3,6 and 7 are unarguable. 4 relates to encapsulated grp keels and would worry me more than keel bolts - I once saw a boat with an encapsulated keel legging it as fast as he could go to the travel hoist after just one night of being too near a shingle bottom. 6 is also an issue - I once saw Suffolk Yacht Harbour drop a new Island packet because the travelhoist slings slipped forwards and backwards along the keel.
But to me, the real issue is handling. I want my boat to handle with the same sort of lightness, ease and performance as I want my sports car or motorbike. I dont want a caravan with a keel that lumbers slowly along. I am never going to go anywhere near the southern ocean so I dont want a boat designed to cope with the southern ocean - I want a boat for coast hopping round the UK and france and spain and which gives me enjoyment through its handling whilst doing so.
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doug748
Well-Known Member
" Do people with long keelers find they have particular situations that they avoid because of handling difficulties or is it just a matter of doing it in a different way rather than not doing it at all? "
Only racing comes to mind.
You have to be very wary that a quick handling boat, with a novice helm, can force you into the tack under the impression that you can turn as quick as him. A midship t-bone spoils everyone's day.
Only racing comes to mind.
You have to be very wary that a quick handling boat, with a novice helm, can force you into the tack under the impression that you can turn as quick as him. A midship t-bone spoils everyone's day.
King Penguin
Well-Known Member
We do know a lot more about foil shapes, etc but the main reason there are not many companies offering long keels any more is due to costs, ie, they make the boats much more expensive to buy......not because they are old technology.
CAPTAIN FANTASTIC
Well-Known Member
... and therefore are tossed about much more easily because they dont "slide" sideways
westernman
Well-Known Member
No particular situations I avoid (except beating back from Spain into the teeth of a F9 - magic doing it the other way round though). I reckon I can park pretty much anywhere - mostly backwards as the bow sprit means we end up too far from the dock when parking forwards.
pvb
Well-Known Member
Mine doesn't get "tossed about" much.
john_morris_uk
Well-Known Member
I am not sure that is entirely true. Long keels were as much a product of the technology available in boat building terms in times gone as they were anything to do with efficiency. There is also (traditionally) a very large element of conservative thinking in ship/yacht/boat design.
Before the advent of modern construction techniques there were always compromises in terms of hull and keel shape according to what was possible along with what was economically feasible with the construction methods available.
And to answer the previous points re slamming etc. There are plenty of fin keeled boats that do not have pronounced canoe bodies which slam. For example lots of the early Nicholsons/Contessas etc didn't slam in a seaway and yet they would be considered fin keeled boats.
People conveniently forget that long keeled boats are quite capable of wave slap against the forefoot.
There's too much blind prejudice and not enough serious thought in some of the answers people tend to trot out. I will stick my neck out and suggest that the only positive attribute I can find regarding long keels is their ability to track,, and maintain a course without constantly being on the helm but even that is a two edged sword as tracking well means that they can be a pig to tack and manoeuvre.
One also ought to remember that not all fin keeled boats are as twitchy as some of the long keeled addicts would like us all to believe... The non-radical pleasantly mannered fin keeled cruising boats are often conveniently ignored by those who defend the long keels of their chosen boat.
wotayottie
Well-Known Member
Very much doubt this - the cost of a keel casting is trivial in comparison to that of the rest of the boat. On my boat I happen to know that the keel ( and its lead not iron) id just 4% of the boat selling price. In any case, no way would a Bav with a long keel get anywhere near the cost of a Swede.
I can see no reason why a long keel production boat would cost any more to make than a deep fin one - less if anything since the stresses in a long keel structuire are less.
Rossynant
Well-Known Member
One thing of great importance that people forget while discussing longkeel - a definition 
- what actually they are talking about? 
Should I say that popular boats of Folkboat kind for instance are not a longkeel?
They were defined when designed as "finkeel" - keel length less then 1/2 of waterline (keel, to be precise, measured on 'bottom of keel'
).
So some opinions here are for "longkeel boats", some for "rudder attached" boats, some for "V-bottomed", or for "Cut-away forefoot" etc.
This boat - is it long or fin? Originally had rudder on keel, later fitted with spade. This is a RORC racer design
https://picasaweb.google.com/lh/photo/iWhGPx4BXC0Xa2fLejOtTdMTjNZETYmyPJy0liipFm0?feat=directlink
Longkeel: https://picasaweb.google.com/lh/photo/guqhQEbeMtD3eSzbUR3I6dMTjNZETYmyPJy0liipFm0?feat=directlink
Deadwood-cut-away: http://www.timloftusboatbuilding.co.uk/images/pilot-cutter-lines-2_sml.jpg
Forefoot -cut-away: http://boatdesign.files.wordpress.com/2010/01/100122-1.jpg?w=479&h=299
https://encrypted-tbn0.gstatic.com/...0hzMjlfKZc9-k67El7QLuKhWgof51T7ADqKcnRbC1gMuz
Finkeel - and today everyone will call this a "Longkeel" - but hydrodynamic characteristics will be of finkeeled boat: tighter turn, less wetted area, faster and better closewinded, poor controll downwind; only steering under power astern very poor on this config indeed http://easternyachts.com/jaynor/images/inslings.jpg
Handling characteristics depend on particular design feature, not on classification. For instance astern under power - old sailboats were never meant for it - depends on prop position, aperture, rudder configuration; old fishing boats, meant as 'motor-sailers' were behaving better than some modern finkeels because they were designed for it.
Same goes for tacking: finkeel will turn on a dime, longkeel goes in big circle. Fin is better to round the buoy in race, but for tacking up narrow channel give me longkeel - will outrace it, because of this long circle - forereaches in tacking going straight upwind even with small speed, when finkeel is stalled and sags back...
Whole explanations need a book on hydrodynamics
But enough to say that nobody would design a racer with longkeel, for it has a lot of wetted area, so drag; efficiency, in terms of drag versus lift is a lot less. Only way to overcome this is to use more sail area, but this not only is limited by racing rule, more by sailcarrying ability which depends on displacement also, so light boat cannot carry enough, while heavier boat will have more wetted area again and this may still keep her slower in light wind.
Then again longkeel boats often were - and still are - designed for bluewater sailing as for this longkeel offers advantages, while light wind/flat water performance is of less concern - so in such a boat we may expect a lot of other features desirable for offshore going as well. Not having anything to do with keel length.
I'd take my coat...
- what actually they are talking about? Should I say that popular boats of Folkboat kind for instance are not a longkeel?
They were defined when designed as "finkeel" - keel length less then 1/2 of waterline (keel, to be precise, measured on 'bottom of keel'
). So some opinions here are for "longkeel boats", some for "rudder attached" boats, some for "V-bottomed", or for "Cut-away forefoot" etc.
This boat - is it long or fin? Originally had rudder on keel, later fitted with spade. This is a RORC racer design
https://picasaweb.google.com/lh/photo/iWhGPx4BXC0Xa2fLejOtTdMTjNZETYmyPJy0liipFm0?feat=directlink Longkeel: https://picasaweb.google.com/lh/photo/guqhQEbeMtD3eSzbUR3I6dMTjNZETYmyPJy0liipFm0?feat=directlink
Deadwood-cut-away: http://www.timloftusboatbuilding.co.uk/images/pilot-cutter-lines-2_sml.jpg
Forefoot -cut-away: http://boatdesign.files.wordpress.com/2010/01/100122-1.jpg?w=479&h=299
https://encrypted-tbn0.gstatic.com/...0hzMjlfKZc9-k67El7QLuKhWgof51T7ADqKcnRbC1gMuz
Finkeel - and today everyone will call this a "Longkeel" - but hydrodynamic characteristics will be of finkeeled boat: tighter turn, less wetted area, faster and better closewinded, poor controll downwind; only steering under power astern very poor on this config indeed
http://easternyachts.com/jaynor/images/inslings.jpgHandling characteristics depend on particular design feature, not on classification. For instance astern under power - old sailboats were never meant for it - depends on prop position, aperture, rudder configuration; old fishing boats, meant as 'motor-sailers' were behaving better than some modern finkeels because they were designed for it.
Same goes for tacking: finkeel will turn on a dime, longkeel goes in big circle. Fin is better to round the buoy in race, but for tacking up narrow channel give me longkeel - will outrace it, because of this long circle - forereaches in tacking going straight upwind even with small speed, when finkeel is stalled and sags back...
Whole explanations need a book on hydrodynamics
But enough to say that nobody would design a racer with longkeel, for it has a lot of wetted area, so drag; efficiency, in terms of drag versus lift is a lot less. Only way to overcome this is to use more sail area, but this not only is limited by racing rule, more by sailcarrying ability which depends on displacement also, so light boat cannot carry enough, while heavier boat will have more wetted area again and this may still keep her slower in light wind.
Then again longkeel boats often were - and still are - designed for bluewater sailing as for this longkeel offers advantages, while light wind/flat water performance is of less concern - so in such a boat we may expect a lot of other features desirable for offshore going as well. Not having anything to do with keel length.
I'd take my coat...
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Conachair
Guest
More hull to scrub and paint
And pig in reverse but you get used to that. They probably start coming into their own more long distance cruising, drying out against walls with unknown bottoms, simplicity of a rudder strapped to the transom, easier life for a wind vane etc. Single handed you not so strapped to the tiller either.
john_morris_uk
Well-Known Member
What exact advantages are offered? People always make this claim, yet I have sailed across oceans in various keel configurations and I am not sure I buy into this 'long keeled myth' any more. I suggest that a moderate fin can be just as seakindly yet much faster than a long keeled 'classic'....
All my fin keeled yachts have dried out alongside a wall without any problem at all. Rather better than some 'long keeled yachts' have done in fact...More hull to scrub and paint
And pig in reverse but you get used to that. They probably start coming into their own more long distance cruising, drying out against walls with unknown bottoms, simplicity of a rudder strapped to the transom, easier life for a wind vane etc. Single handed you not so strapped to the tiller either.
Conachair
Guest
Was thinking more of the increase in piece of mind as the water goes down tied up to some rickety pier in the back of beyond far from assistance and with no idea what lies beneath the oozing mud...
Rossynant
Well-Known Member
First to the last - yep, but as I said - you may be thinking of finkeels, or rather "cut forefoots" - even could say the names
Well, mine stands at the moment in the open (with her legs, no wall needed), no falling on the nose... On oceans - depends what conditions you talk. Any boat will make by tradewinds route, no prob.
And once again - it's length of keel, geometry, that matters - not to be confused with "attached rudder", though rudder attached to something is less prone to stall so better in turbulent, confused flows.
Advantages?
- Roll damping depends on keel area and length. Longkeler may have more area and usually have more length by definition. So motion easier, less risk of knock-down, broach etc.
- Range of angles of incidence at which the keel works - depends also on other things, but on aspect ratio mostly. Also on speed, strictly speaking on relation between speed and length of keel - Reynolds number, "flow velocity". Re depends on speed x length of keel, you may check what stall angle is in various coditions for given length of foil. Like for instance in average going AR 2-3 stalls at 20 degrees, AR 1 at 40, AR 0,3 works almost to 80 deg. Roughly, just to show difference. In seaway on big waves, boat rolling and crossing orbital currents at rather small speed, you can imagine what angles may happen. Stalled fin makes boat unmanageable and drifting, if only for part of time.
- Smoothing the flow, by mechanism probably called "memory effect" in english, or Wagner's effect. Roughly: flow of water will not change - even if boat or water around changes direction or angle, or speed - for some distance flown, say about 6-10 times the length of travel, so a length of keel
This is exactly the reason why longkeelers are slow to respond to change. For flow around the keel (or rudder or whatever, sails included) to change they have to travel some 6-10 lengths of keel. This works the other way around when you want a boat to behave correctly in unsteady flow conditions. Changes in flow for less than 5 times keel chord, or for a time shorter than this distance is travelled, will not affect the boat. And all the rest of 1200 pages on aerodynamics...
PS. Effective aspect ratio (of keel or any foil attached from one side, sealed base) = 2 x height / length in case someone is curious; height - vertical measurement (so not to confuse); length should be mean of horizontal measurement.
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Rivers & creeks
Well-Known Member
They make nice family boats. Or boats for nice families, I forget which.
Avocet
Well-Known Member
I don't think it's fair to say that some of the advantages (and disadvantages) are "nothing" to do with a long keel. Whilst it's true that they're not STRICTLY functions of keel design alone, it becomes very difficult to actually completely separate the two, (on any kind of boat) and as the OP was (presumably) intending to buy the whole boat, and not just a long keel, I think they'd "go with the territory"! The worse ability to tack can be an advantage if single-handed. it all happens that bit slower, giving a bit more time to get the job sheet hauled-in. Obviously not an advantage when racing round the cans with an experienced and energetic crew though.
Yes, I suppose I should have made more of the lack of leeway. It is pretty good. I see it as part of No. 7 really. The thing is, looking at the whole boat, although Avocet doesn't make much leeway, she can't point quite as high as a more modern boat with the latest rig design. Again, you might say that's nothing to do with the keel - which, of course, it isn't, but taking the "whole boat" into account, I think it is truer to say that long keeled boats GENERALLY aren't going to have high performance rigs.
I'll have to disagree on them being less likely to get stuck when grounded. Whilst there might well be some designs of long-keeler that could get themselves stuck, most of the ones I've seen seem to have the right sort of shape for sliding backwards off the obstruction - particularly if you just send a bit of weight forward for a few minutes.
As for worries about encapsulated keels rather than bolted ones, I think there are more threads on here about keel bolt problems than encapsulated hull problems. I've hit the rocky bottom of Windermere quite hard once and only needed a bit of epoxy filler before the next antifouling. You'd have to try quite hard to actually pierce it! (AND I never have to worry about my keel rusting)!
Finally, I'd (strenuously!) maintain that you don't need to go as far as the Southern Ocean to reap the benefits! The boat we had prior to Avocet was a fin keeler. Same waterline length (give or take), much broader beam, and only about half Avocet's displacement, so I can't make direct comparisons, but even in the short steep waves of Morecambe Bay, there were huge advantages in terms of both comfort and progress, to having a fine-lined long keeler.
LittleSister
Well-Known Member
The need for compromises didn't stop with the advent of 'new' technologies! (And the old ones were new once.!)
Long keels are less fashionable now, and I would expect the additional cost of moulding a long keel would likely outweigh the strengthening needed to cope with the stresses of all but the most extreme fin keels.
If you want to maximise your speed above other considerations, don't buy a long-keeler, but they are not inherently as slow as some would have you believe, especially in real world cruising terms. All boats are compromises. The slight 'cost' in speed is insignificant to me, but I really enjoy the gentler motion and 'little ship' feel of our little long keeler. Our boat was rather expensive new. If long keelers were more fashionable we probably couldn't afford to have bought it second hand.
The value of deep 'bilges' has been mentioned but easily overlooked. Have a look at where the weight of the fuel and water is in the drawing of the long-keeler above, compared to the average modern fin keeler. (I'm definitely NOT saying fin keelers are bad - I'd be happy to have one - there's just a different set of compromises
There is no doubt that in general long keelers will be less prone to slamming, though quite likely there are some that do, just as there are fin keelers that don't. But the average flattish bottomed white boat will slam more than the average manky auld long keeler. (On an Atlantic trip I really began to fear for the integrity of the hull, let alone my nerves, from the slamming of the AWB we were on.)
The argument that long keels are obsolete because they are older technology - like 1930's motorbikes, someone said - is nonsense. 1930's motorbikes still used wheels. Sails and hulls are prehistoric technology. Are they obsolete?
Hope the OP enjoys whatever he chooses.
Rossynant
Well-Known Member
Should have mentioned the most important 'compromise' connected with keel length
Deep, high AR fin is more efficient close-hauled, for windward beating; while long, low AR - for reach or downwind going. So choice is also about which direction we want to go more often (and we all know gentlemen... etc).
To clarify: for windward we need big lift force (sideforce) generated with small drag. Deep fin is more efficient with this, producing, typically, twice more lift per area at normal angle of drift. As the force must be obtained (or boat will not go at all) longkeel needs twice more area for this, causing more drag.
But when the boat is not going upwind, so 'pressed aside' - the angle on which keel is working is less, or 0 and in such situation longkeel makes less drag.
The same principle which applies to 'gaff rig versus bermudian' controversy; which one is "better" depends on what point of sailing.
Lets keep in mind that finkeelers were designed in XIX century, exactly because of this reason - they were made specially for 'round buoys' racing - it's not a "modern technology" at all...
To illustrate the idea: https://picasaweb.google.com/lh/photo/8HG1_0adPKMYE6puboqDkdMTjNZETYmyPJy0liipFm0?feat=directlink
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MASH
N/A
Wow!
So now I know what sort of keel I need I just have to decide what sort of hull and rig to stick on top of it. We're getting there!
But seriously, thanks to all for an entertaining and very informative discussion.
Now, about these gaff thingies...
So now I know what sort of keel I need I just have to decide what sort of hull and rig to stick on top of it. We're getting there!
But seriously, thanks to all for an entertaining and very informative discussion.
Now, about these gaff thingies...