Converting a twinkeel to a finkeel

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zeeotter

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Is there anybody who have ever done this? Remove the twinkeels from a sailboat and replace it with a lead finkeel?
Would this be technical possible? The boat in question is a westerly fulmar.

Gerard Versluis
 
[ QUOTE ]
Is there anybody who have ever done this? Remove the twinkeels from a sailboat and replace it with a lead finkeel?
Would this be technical possible? The boat in question is a westerly fulmar.

Gerard Versluis

[/ QUOTE ]

You is 'aving a laugh............right? /forums/images/graemlins/crazy.gif /forums/images/graemlins/grin.gif
 
I have seen it done to a Westerly many years ago at Universal shipyards on the Hamble. My understanding is that twin keel boats have to be laid up more thickly than fins to withstand the greater forces involved - this extra laminate normally runs right under the bilge so you may well find the laminate substantial enough to bolt the fin to. You then just have some holes to seal where the twin keels were :-) Talk to a good surveyor / laminator.
 
Often the mouldings are different, a fin keeler usually has a substantial moulded stub where the keel bolts on, unless it's encapsulated of course. I have seen some bilgers that still have the fin keel stub but most that I know of don't. I suspect it would be quite an expensive conversion, nearly all things are possible though with enough cash /forums/images/graemlins/grin.gif
 
Don't even think about it!
Of course it is technically feasible - but it will cost a hefty sum.

The Owner of this twin keel Fulmar would be much better off if he / she sold it, to someone who wants a twin keel Fulmar, and then buys a fin keel version.
 
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Don't even think about it!
Of course it is technically feasible - but it will cost a hefty sum.

The Owner of this twin keel Fulmar would be much better off if he / she sold it, to someone who wants a twin keel Fulmar, and then buys a fin keel version.

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Ah Martin, you so much more diplomatic than I, I will have to come to the Windies and get you to give me some lessons, probably best, if I don't tell you whan I am coming though, as you would probably arrange to be out! /forums/images/graemlins/grin.gif
 
[ QUOTE ]
I have seen it done to a Westerly many years ago at Universal shipyards on the Hamble. My understanding is that twin keel boats have to be laid up more thickly than fins to withstand the greater forces involved - this extra laminate normally runs right under the bilge so you may well find the laminate substantial enough to bolt the fin to. You then just have some holes to seal where the twin keels were :-) Talk to a good surveyor / laminator.

[/ QUOTE ]

I don't know about Fulmars specifically, but I have had clients with Centaurs and Pagaents which have done the splits (after twenty five years or more good sailing it must be said) precisely because the hull laminates between the keels were not as strong as they should be.
 
Could be done, by a good boatbuilder. As a DIY job, you would end up with a worthless and unsellable boat. But what is the point?

Spend thousands and ruin a (presumably) perfectly good bilge keeler, or sell it and buy one with the keel config you want? Should be pretty well a straight swap price wise, and no depreciation on resale value. Also a whole lot quicker once you find a buyer.
 
Hi Gerard,

Hope things are well with you and your family.

I wouldn't consider attempting a change. As you will know, the fin version has a moulded 'stub' to which the keel is attached. The construction/stength of this is truly massive and would be next to impossible to achieve retrospectively without massive cost. Even then I would always feel edgy in heavy weather.

As mentioned above, I would edge more towards selling your very well looked after boat and replacing it with a fin version.

Sorry I can't be more positive.

Have a very happy and healthy new year.

Kind regards Jerry
 
[ QUOTE ]
Is there anybody who have ever done this? Remove the twinkeels from a sailboat and replace it with a lead finkeel?
Would this be technical possible? The boat in question is a westerly fulmar.

Gerard Versluis

[/ QUOTE ]

Why would you want to do that? There have been loads of tests showing that there is little difference if any at all between bilge and fin keels on the same hull. It will cost serious money and given the scarcity of decent bilge keelers you are even likely to reduce the re-sale value of the boat.
 
I notice in your bio that you do not say where you are located. The UK posters can't imagine why you would want to modify a bilge keeler. However if you lived in a part of the worlld where there is little tide and possibly strong winds then there would be more incentive. ie less resale value for the twin keeler and more value for the fin keeler.
But for all that the job willl be huge and you would never feel totally confident about sitting the boat weight on the keel on the hard or running aground at any speed or in any large sea. I saw a little f/g keel boat sat on it's keel on the hard and the hull around the keel promptly let go and the keel ended up inside the boat.

Now just waffling on the actual design.(I have no skills in this area at all) You could have steel keel fabricated out of sheet steel or cast out of cast iron. It would need to have a big flange to spred the load and to accomodate bollts each side, wide spaced. You should add more layers of fibreglass to the hull bottom and glass and additional floor beams.
Don't forget the additional strength fore and aft of the keel. Some years back Australians lost an Americas cup challenger when the boat broke in half at the keel. The weight and pendulum effect of the 12 ton very deep bulb keel coupled with other problems caused the hull to break in half.

The actual keel design could include additional mass at the bottom in the form of a bulb or even winged keel.

I went for a sail on a friend's new Thompson 9.8 last Wednesday. It was a real goer especially with a huge assymetrical spinnacker on a bowsprit type retractable pole. Any way it has a 2.3 metre draft (thats a lot for a 30ft boat) She seemed more concerned about the depth sounder reading than anything else as we sailed around the Swan River. I don't think I would want a boat with so much draft.
I took a swim a few days later and looked at the keel. It is incredibly thin not very big chord of presumably carbon fibre with a 1 ton torpedo shaped bulb on the bottom. This boat I understand has a semi retractable keel in so much as you can loosen the attachment form inside the cabin so when it is craned onto a trailer the bulb and keel can slide up into the cabin.
That would be fortunate as she has just towed the boat on a trailer 3500km from Melbourne despite the near 10ft beam.

Good luck and I hope you are just day dreaming about the Fulmar fitting a fin keel. olewill
 
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Why would you want to do that? There have been loads of tests showing that there is little difference if any at all between bilge and fin keels on the same hull.

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I desperately wish to imagine that my twin-keel Foxcub could be as quick as a fin-keel version but I simply can't see it.
 
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