more direction from bilge keels

[humyar]

Hello,

I am wondering if I could run this past you: If I added a leeboard to a bilge keel boat would it improve it's direction when on a tack plus how bad are Bilge keels in the way of their lee?

Thanks alot,

Alasdair

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[VicS]

Boats vary enormously. Some bilge keelers are claimed to have a windward performance almost equal to their fin keeled counterparts others are legendary for the amount of lee way they make.

As your profile is silent about the type of boat you own it is impossible to make a more useful comment.

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple>

 

[Guest]

the older BK boats are notorious for leeway - especially Macwesters etc.

Later boats that quote Twin keels are far better - as the keels resemble more twin fins.

Adding leeboards ..... is it really worth the hassle ? and it would have to be of reasonable size to have effect ....


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/

 

[tyce]

hi i have a hunter horizon 272 twin keel, and when the rigging is correctly tuned and its in the right hands, most fin keelers have no advantage, and, are some times worse if rigging inefficiently set up, as for leeway i can virtually discount it.
but be careful some bilge keelers are very poor performers, you wont go far wrong with a hunter.

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[Avocet]

Ive a feeling thatthe extra drag of the additional board might offset any advantage in lack of leeway. It might juts be better to sail a bit faster and put in a couple of extra tacks.

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[Guest]

It\'s a ? of what you want from your boat

Do you want ability to dry out ...

Do you want to race....

.......... the compromise is the twin keel approach .... but you also suffer increased draft, less surface area of keel to stand on, there are other factors as well ....

Bilge Keel is my preferred in UK without adding unnecessary additions. I accept I cannot go to windward as well, I accept my leeway is greater, I accept that I cannot sail as fast etc. etc. - but the main thing is I like my boat, I get there and I have a good time. I have a fin keel racer in Estonia ..... fine - but I would not have it in UK as my cruise / main boat, I have twin - YES TWIN lifting keel boat in Latvia and that is a good compromise , but too light for UK conditions - I would have to ballast her down more - losing the benefit of the twin lift keels ....


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/

 

[charles_reed]

Bilge and twin keelers

In the past bilge keelers have had a deservedly poor reputation for the leeway they suffer on a beat.

However recent boat designs, especially in France, have re-discovered twin keels, hydrodynamically efficient and probably as good as a long-keeler in preventing leeway.

I'm afraid this doesn't answer your question - there is insufficient information to do so.
If it's a recent design and the keels are angled from the vertical and the fore/aft axis it's likely that all you'll do is slow down the boat and probably increase the leeway.
If it's an earlier design, you may improve the VMG at certain speeds but you'll only be able to find out by trial and error.

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[charles_reed]

May I point out

that Open racers are effectively twin keelers - that long pendulum in the centre is just that, a counterweight hung out to windward - whilst the leeward, lowered daggerboard acts as the fulcrum of effort.

So twin keelers don't have to be sluggards, and you don't have to have vertical, hydrodynamically-inefficient bilge keels to dry out.

In any case you only reduce draft to about 65% of the fin-keel version.

Far better to have a lifting keel such as Ovnis, Southerleys, Parkers to name but a few boats which will find their way into 2' deep channels and dry out flat and close enough to the seabed to be able to get on and off.

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[oldharry]

Major mods of that kind are rarely worth it - firstly its not easy to get any significant improvement, particularly 'uphill'. secondly it would almost certainly reduce the value, possibly even making it almost unsellable except at give away prices.

Better to sell up and start again if you are not happy.

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[AndrewB]

Precisely.

Though it can be fun to experiment, if you like the boat and aren't bothered about the resale value.

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[Guest]

To Charles Reed ....

I agree and am fully aware of what you quote ..... I am answering - albeit assuming the case !! - in regard to normal cruise etc. boats that most look to buy / use - not the specialist ballasted hinged keels types etc. etc.

I also agree totally about the lift keel boats such as Feelings / Southerly's etc. - fine and real versatile boats that also sail reasonably well.


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/