Fin Keel? Long Keel?

There's long keel, and longish keel...and there's the question of beam. Long keel designs often have a narrow beam and are very easily driven to windward, with no slamming and little if any load on the helm when heeled. Add a cut-away forefoot and good size rudder (think Folkboat) and you really do have the best of all worlds. It's a pity there are so few available like this now...
 
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a cut-away forefoot and good size rudder (think Folkboat) and you really do have the best of all worlds.

[/ QUOTE ]You are very correct if you are referring to sailing performance. I grew up on a Folkboat and I think it is still a sailing design hard to beat. However, we have all grown older and more desiring our creature comforts. My first two Folkboats did not have engines nor heads. I love the comforts of my modern cruiser/racer while I treasure the memories of my Folkboats. But there is no going back.
 
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"I love the comforts of my modern cruiser/racer while I treasure the memories of my Folkboats. But there is no going back."


Well now there isn't but I was very luck that when I grew out of the folkboat I got a chance to buy a 32' version. Not in fact a contessa etc but a real wooden one that is exactly the same dimensions and profile as the origional and sails just like one to. So all the fun of a folkboat but with stove, fridge, shower and HEADROOM!! She is called a checkstone 32 but unfortunatly is the only one they ever built.
 
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Nobody has really mentioned the "in between" types of hull configuration here, what's the consensus on the sort of 70s/80s boats typified by Westerlys, older Bavs, Gib'sea etc. A lot of these don't have the long keel and wine glass cross section of a classic cruiser, but nor do they have the sailplane wing style keel and half a teacake cross section of the most modern AWBs.

Do these compromise boats have any credibility as long distance cruisers or any as comfortable liveaboards with reasonable performance.

How do they compare for stability with the boats at the extremes for example..

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Hi
Check out the thread "Plugging in the numbers" , there is a spreadsheet link in there to dl.
It is a great starting point to answer some of your questions, the basic answer for me is YES, some of the older bavs, gibseas etc etc can and DO make superb crusing travellers / homes for good reason, they are a great compromise, check out the gibsea 441 for example. Even the 402.

Our choice was based on the fact we didnt want modern fin and skeg, flattish hull etc.. the ideal compromise for us was a long fin or modified full keel.
As to the question of comfort, the basic ideas of motion comfort can be seen in the figures in the spreadsheet, the actual comfort and space to live aboard for you and your toys is a personal preference. Note my spreadsheet although including LOTS of boats is based on boats with Load water line >= 25 and <=35, you may want something larger depending on crew numbers, choices etc.
What the Numbers" do, is give you a way of ruling out many boats based on your own wants and preferences. The sheet also allows you to plug in numbers for any design not listed, the only ones listed there are the ones I could obtain accurate data on.
Our first "rule out" decision was anything with CSR > 1.95 , then we looked at CR, then looked at examples of boats that looked good on paper to compare one with the other for our needs. Even then, extremes of figures are susually for a reason !
Hope that helps.. we are very happy with the approach we have taken.

Joe
 
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>a passing wave will produce differing forces at the bow and stern (far more so than on a shorter keel) so the long keel is more easily disturbed in a seaway.

Don't know where you read/got that from but having sailed both types of boat the exact opposite is true. Waves shove fin keelers around (the wider the aft sections the worse it is), long keelers just plough on

[/ QUOTE ] I got the comment from the physics of the subject.

The experience driving your (correct) observation would be of a high displacement long keel against a low displacement fin keel.

Quite deliberately, I avoided the question of inertia in my post just to simplify what I was saying. You'd certainly be correct to say that boats with high rotational (yaw) inertia react much less to wave disturbances than those with lower yaw inertia.

It just so happens that most long keel boats not only are heavier for their length, but also have more weight in their ends. So, sure, they just plough on. Distribute weight (and the amount of it) in the same way in a fin keel, and it would plough on too! And the probablity is it would plough with even less disturbance.

The inertia effect is obvious when you look just at boat size. Other things being equal, bigger boats are less disturbed by waves . . . simple really.
 
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First, lets all agree that long keels don't do windward efficiently. So, if you want to be able to do windward, don't do long keel.

I agree with most of what you say Jim, but would take issue (a little ) with the above,

[/ QUOTE ] And why not? I accept your point that that a good helmsman in one boat (and not the other!) can cancel the difference.

Especially if the long keeler is a knife edge design, like the Baltic 8m and 12m yachts of the 30's. Now, they really did go to windward efficiently. But they were hardly live-aboards (too narrow down below) and their ptich and yaw inertia was so high that, in a seaway to windward, too much time was spent with the helmsman under water! But, boy, they went straight.

No wonder, then, that they were a success in the flat water of the Baltic.
 
Personally, I find it great fun overtaking (theoretically) faster boats to windward with a 11 ton/27ft LWL long keeled ketch /forums/images/graemlins/grin.gif As we shall want to up-size at some point, it's quite a useful comparison performance-wise to sail against potential 'new' boats. It's also disappointing, in some ways, to leave them behind as we're not changing for a larger boat only to find inferior performance!

My main point was that the uninitiated should not be led to believe the bald statement that "if you want to be able to do windward, don't do long keel."
 
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First, lets all agree that long keels don't do windward efficiently. So, if you want to be able to do windward, don't do long keel.

I agree with most of what you say Jim, but would take issue (a little ) with the above,

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Also,my tuppence....

firstly, WHY do you WANT to go to windward efficiently. ?.. yes, we have all learnt about lee shores etc etc... but in reality, the oft used term "gentlemen dont go to windward" is more than a bar room boast.. its NOT comfortable.. so why do it unless absolutely necessary ?.

Look at the theory of modern keel design and lift.. the reason the modern boat, and many older designs too !.. were fatter aft ?.. on a heel, it tilts the keel giving a lift and righting moment not designed in by sheer ballast.

Then, there is heave to situations et al... most modern underwater profiles dont.. cos they are designed to be driven, and as said, stall inneficiently when no motion is applied.


as for the "good helmsman".. an interesting take... yes, many a helmsman can make a boat do wonders in a dicey situation, but not many helmsmen / women ? exist, or, are awake and alert enough to do so on a passage maker with minimal crew. the reliance on AP´s is very great, for very great reasons.

The doubtful windward capabilites of certain designs are oft´misinterpretted imho. Pounds, slams, makes headway.. yes ?, but first you HAVE to be in the situation you WANT or NEED to do this, often simple good seamanship (Also called basic common sense) negates this.. if the excrement hits the rotary oscillator, you often have a modern type yacht diesel to make passage to "windward"...

Joe /forums/images/graemlins/wink.gif
 
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firstly, WHY do you WANT to go to windward efficiently. ?..

[/ QUOTE ] Well, it does depend a lot on the type of sailing you like to do. Once I've arrived in a new cruising area, I love doing lots of day sails to explore the area thoroughly. Circling a 20nm island inevitably means windward time. And working north past the Rias where you are is strong wind windward work, mercifully, in flat water. And I prefer to do without engine if possible - a sort of pride in doing without. And, being impatient ot see more, I prefer not to be held up waiting for headwinds to abate (which doesn't happen much in the areas above!)

Ignoring tide elements, the angle between tracks of a fin keel is going to be about 100 degrees, of a long keel about 120 degrees. The resulting speed made good to windward in a fin keel is going to be nearly 30% quicker - for a vessel that makes 6kts on the wind, the difference between 3kts and nearly 3.9kts to windward.

Now half an hour in three hours isn't too much to worry about, but if you're butting into even a small a current, the picture is very different - 2kts vs 2.9kts.

Working north along the Portuguese coast is a case in point. It's not really feasibe in a long keeler under sail alone with the current running at about a knot, making only 2kts to windward, so long keelers are committed to a voyage, two days out to the west, then a couple of days back.

Fin keelers can work north along the coast making 3kts to windward - 20 hours covering the longest hops needed between harbours, against 30 hours.

So you have more options with a better windward efficiency. And I guess that makes me not a gentleman - I don't mind windward, as long as it doesn't go on too long!
 
"design me a baot that is as light as possible for speed but has plenty of weight to gve a comfortably motion in a seaway!"

aha !.. Nirvana.. it aint got there yet, and probably never will.. cos you need to define your seaway also..

/forums/images/graemlins/smile.gif

Most modern boats are NOT designed to go long distance..

MANY older designs were..

take the existence of sugar scoop monstrosities on the back of some boats, well, err, many ??

WHY ?.. cos it worked in the racing rules to try to equalise performance... and the average numpty wants one that looks like this.. thats WHY they are here,, yes yes lol, many try to justify this with "I WANT a swim platform, etc etc..".. but the hard truth is they bought a 42 footer with 5 foot of nonsense at the back so that, in their dreams, little woman can swim off it and have somewhere to brasso the candelabra and hand cut cyrstal galsses on..... ,), so its good?... No, it´s generally not, its a design trend for RACING RULES, n ot waht makes a boat seakindly or comfortable , or indeed, a passage maker as most understand the term, nothing more, Just to suit the masses of the great unwashed at the latest boat show.

Spade rudders, skiff profiles, for racing, money no object usually.. noone can compare, realistically, an open 60 with a modern cruising yacht, MILES apart, and using a 70´s 80´s CR as a comparison doesnt work well.

Shallow profiles make good speed at the expense of comfort, not needed on a racer.. less wetted area makes for speed, needed on a racer... The profile is designed to be driven, not hove to or stopped for a rest, not in the brief !

YES, there are exceptions, but perrrrrrrrrrrrrrrrlease...... !! ,), the AWB is the epitomy of boatshow wives and the need of the "man" to have something the little woman accepts.... along with the silver candelabra and hand cut waterford glass. and possibly, a nice bowl of Geraniums and a flight home..

The marketting world gone mad, but only in response to an audience mostly receptive of hype.....

Nurse ?? wheres me flamazene ??? I had a tube SOMEWHERE ??, maybe next to me zimmer........ ?


/forums/images/graemlins/laugh.gif
 
Sorry Jim lol, couldnt resist this... PLEASE forgive..... /forums/images/graemlins/blush.gif

"Circling a 20nm island inevitably means windward time"

NO ! it doesnt /forums/images/graemlins/wink.gif ... just use the southern pacific 3.1 ali floor rib with around 18hp on tap... no wuckin furries.. and the stately home stays put... soaking in the rays from the overpriced and inefficient solar panels... Whilst we "nip" arond the area with less hassle.... /forums/images/graemlins/smile.gif

whilst, of course ... the cost of petroleum used is probably less than me trusty and reliable old Yam 2b given the time v distance equation..

and, lol, before some "person" come on here all green, salty and "experienced" re an imagined noise polution.. ballcocks I say.. I run the rib less time than those "sailors" run their diesel to try to make up for an inefficient charging system, however, I digress..

/forums/images/graemlins/laugh.gif


Ahhhh. bliss.........................................

and, Ahhhh ........... Bless /forums/images/graemlins/wink.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif
 
Slarty, you don't half talk twaddle on occasion.

"Modern boats are rubbish, not fit to cross the Serpentine" and other idiotic statements. Humbly suggest you engage the brain occasionally.

For a modern ocean cruising rocket ships take a look at Dashew's designs and my favorite Dark Star Sure she's got an awful lot of draft, but the design lends itself to a lifting keel.

Incidentally, how are your interior modifications coming along?
 
Thanks for all the feedback on this subject. However it seems to have confused me more and more. All this talk about heavy displacement and inherent stability is only part of the picture. So after all the debate I feel it comes to this.

If I feel that I am likely to spend a significant time making ocean passages then maybe a long keel could make me feel safer ....but I am not convinced. I have read somewhere (a book storm tactics) that what knocks a boat down is not wind or wave BUT a breaking wave AND a breaking wave is capable of knocking down any small boat.

So....do I compromise beam and space and headroom in my living environment on the of chance I go ocean cruising or accept the theoretical limitations fin and spade yachts have and enjoy the benefits such a boat offer for the other 80% of the time on board??


Dave
 
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So you have more options with a better windward efficiency. And I guess that makes me not a gentleman - I don't mind windward, as long as it doesn't go on too long!

[/ QUOTE ]I agree with you, Jim; a boat should be able to handle all situations you encounter. Windward conditions are unfortunately something you will meet if you are doing more than just weekend sailing.

Last time I was in in Gibraltar I met two 'longkeelers' that had been stuck there for a week, The winds were steady westerly and they just could not get out of the Gib straits because their boats would not sail that wind angle. I would hate to be in that situation. The argument given above that 'you use your engine then' does not really always apply either; many old traditional 'long keelers' also have old small engines that just does not have the horsepower to go against wind and tide. Again, not a situation that I would like to find myself in. I have also sailed many of those 'old' boats and many are lovely. But for ocean conditions; give me a modern cruiser/racer any day. Much safer IMHO.
 
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If I feel that I am likely to spend a significant time making ocean passages then maybe a long keel could make me feel safer ....but I am not convinced. I have read somewhere (a book storm tactics) that what knocks a boat down is not wind or wave BUT a breaking wave AND a breaking wave is capable of knocking down any small boat.


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Yes it is waves that cause knockdowns not wind, which makes a large part of the stability figure argument worthless IMO other than as an indicator. A better safety factor against knockdowns is boat length rather than ballast ratios, but any small boat can always be capsized by the 'right' breaking wave. A more important feature of stability curves than AVS is the area below the line that relates to how quickly a capsized boat might self right, some designs of raceboats around the 1979 Fastnet were as stable upside down as right way up, just like multihulls, but that is sorted on monos by better more buoyant above deck design. Also the figures in the 'plug in' post don't take into acount how deep the keel is or it's centre of gravity, particularly relevant to deep keels with bulbs or wings at the foot. A long keel that is relatively shallow needs to be much heavier than a fin keel that is deep just to have a similar leverage effect, but it then makes it look good in ballast ratio figures as it nears the magic 50% mark. We sail on the sea not on spreadsheets.

As for windward ability yes it is necessary, even excluding any ability to claw off a lee shore. If you cannot sail efficiently in the 90 degree windward sector and add to that the rolly slow 80 deg sector downwind just leaves only half the wind circle available for any enjoyment. Small wonder then why so many so called sailers are really just mobos with wind assistance.

It is perfectly possible to design a fin keeled boat that keeps a steady course, we have one. We have a pilot that occasionally switches itself to standby without warning, sometimes after 18hrs or more of behaving impecably, but it often goes unnoticed for some time because the boat keeps going on her own, especially so upwind. It is equally possible to design a long keeled boat that is a real pig to sail, heavy weather helm being quite common. I believe Chichester was very critical of Gypsy Moth despite his achievements in her.

The relationship of weight to comfort too is not as simple as it might seem either because again design comes into it. Some people prefer the long slow movement of a heavy boat in a seaway, others prefer one that is more buoyant and lifts more to the seas rather than plowing straight though them. One old OYC boat was nicknamed 'El Sub' because of her preference to dive under the waves. Also there are lots of people who prefer multihulls to monohulls for ocean cruising, no keels and much lighter but they would fare badly in a mathematical comfort ratio formula.

Significantly many of the respected designers of traditional boats moved away from long keels to fin keels, with both skeg hung and spade rudders. Look at Van Der Stadt designs for example shifting from the likes of Excaliburs (long keel) to Pioneers (fin and spade) as long ago as the late 1960's. Holman and Pye too switched from the likes of Twister and Super Sovereign etc to Hustlers, UFOs, Oysters, Centurians, Gladiators, and many more. Did these designers suddenly lose their marbles or see the light?

Let's go back to performance. We sail a boat that is a joy to sail in light winds, goes to windward really well and is equally good in heavy weather. What is really pleasurable however is that we can sail in F2 when most are motoring. How many boats are there that 'need a bit of a blow' to get going? To my mind if it isn't fun until you see F4/F5 and F6/F7 is too much then that leaves a very narrow band where the wind is 'fun'. Our fun band is between F2 and F6, pretty well covers most conditions we meet regularly and even a downwind blast in a F8 is fun if we chose. In case that gives the impression we sail 'light', those that know us will find that laughable. We carry full fuel and water tanks, every locker on board is full, we have heavy ground tackle, full food lockers and fridge and we have spare parts for spare parts as well as carrying full tookits that get used like A1 Tool Hire.

By way of illustration a year or so back we were headed east along the North Brittany coast on our way home from Southern Brittany. The wind as it does had gone round and was directly on the nose for our course from L'Aberwrac'h to outside of Batz and thence to Perros or Treguier, it had also shifted up in strength to the top of F5 bottom of F6 AND it was spring tides so wind against strong tides and big seas. The nice thing at least was that it was warm and sunny, we were making 7kts hard on the wind and 4.8/4.9kts VMG (boatspeed not groundspeed), we had 2 slabs in the main and the genoa rolled down to working jib size, the sprayhood as is usual underway was folded down and yet back in the (aft) cockpit we stayed dry. We then caught up with a 40ft long keeled ketch going the same way. We knew it was long keeled because we got to see most of it as we passed it by, it was pitching and slamming madly under engine, main and mizzen even though it was motorsailing and 'tacking' upwind, presumably because heading into the seas was even less productive. Stupidly an hour later off Batz we realised we were not going to carry the fair tide to our original destination and to avoid another tack out to sea turned the motor on 'just to clear Isle De Batz' then we could lay Trebeurden on one tack and carry the tide too. UGh!!! We too were now pitching and slamming like the ketch we had passed earlier, we stuck it for just 10 minutes then unrolled some headsail shut off the donk and headed out to sea again. We arrived in Trebeurden on the last of the fair tide and the ketch came in nearly two hours after us, we had sailed (all but 10 minutes) they had motorsailed but two similarly sized boats and BTW the ketch had left L'Aberwrac'h over an hour ahead of us in the first instance. We had a really enjoyable day but I'm not sure the crew on the ketch would have agreed about theirs!

Then there is the liveability factor. We have a really good galley, big fridge, comfy cabin, comfy cockpit with bimini cover convertible to full conservatory, loads and loads of locker and stowage space, a total of 11 opening hatches for light and ventilation all of which have blinds and bug screens when needed. It has to beat being snug below in a dim and hot cabin peering out of storm shutters doesn't it?

As a final comment, we have a full sized nav table which is perspex covered over the Yeoman plotter (we have screen plotters also) so can be used as additional galley space in harbour. There is no way I would hack this out to make room for another seat! We also have a swim scoop stern which is a real bonus, boarding from the dinghy is easier and much safer plus we use it regularly for swimming and washing - swim, soap up, dive in to rinse then back on the scoop to wasdown with the built in freshwater shower.

So there is in my opinion no 'right' answer to the perfect boat but there is one that will be absolutely the right one for you. Just don't let other's prejudices (mine included) get in your way!
 
Very well said!
Robin, your comments above would (I am sure) form an excellent basis for a magazine article, perhaps mentioning the input and thoughts from the other contributors as well.
How about seeing if YM might be interested in such an article?
 
I belive Mike Pocock a designer who also sailed desiged some great multi task boats wrote severaql articles on this subject.Having been owner of a heavy long keeler I would go the way of medium disp with strog fi and skeg.Long keel are traumatic in confined spaces and although keep going well i a straight line are heavy on the helmIhave been sailing a Nich 32 recently great uder self steering ,a classic but I foud it was impossible to leae the helm free uder sail and especially power whereas my old L/keeler just jogged along .
 
Odd Mogy, My Nic32 is well balanced under power and sail, and goes to windward like a train and will keep going into a sea when a lot of light displacement fin keelers are going sideways. Her vice ok, is going astern, needs forethought!
 
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