Bilge keel profiles

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peterlpearson
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Joined: Wed November 11th, 2009, 11:00 am
Location: Ilhabela, North coast of Sao Paulo, Brazil, the sailing capital of Brazil!

Bilge keel profiles

Postby peterlpearson » Sun September 19th, 2010, 7:56 pm

In March 2009 Richard Hare described in PBO adding asymmetrical profiles (foils) to the bilge keels of his Golden Hind to improve water flow along the keels to remove keel vibration. There are extensive discussions in some forums on the possible benefits of asymmetrical foils in twin keeled boats. However, it is not clear to me that these arguments also apply to Maurice Griffith bilge keelers which of course have a central ballast keel in addition to the bilge keels. Have any Eventide members undertaken such a modification and if so were there any improvements in windward performance and increase in stiffness which seems to occur with true twin keel designs? For the record I sail a self built Water Witch on the Brazilian coast in the region of Sao Paulo. Is this the only Griffith designed boat in South America?

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Eventide Owners Group
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Re: Bilge keel profiles

Postby Eventide Owners Group » Sat November 13th, 2010, 11:28 am

Hello Peter,

MG did use assymetric profiles on some designs with wooden bilge keels. however with the heavy mild steel galvanised plates he had another idea.

The toed them in half an inch!

This meant the leeward bilge plate was angled up to windward! Clever.

However we have found that adding a profiled ballast addition to the inside face of a keel, say the bottom 6 or so inches, also has this effect, plus the bonus of putting more weight in the right place! (many early Eventides cured the low ballast this way, simpler than taking off the main keel and adding weight there.

Send some pics in for the Gallery Peter!

Regards,
John
Web site Coordinator

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Fiddler's Green
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Re: Bilge keel profiles

Postby Fiddler's Green » Sat December 10th, 2011, 11:57 am

Just to say the Forum is back up wonering how you are getting on!

Regards,
John
Proud owner and builder of 'Fiddler's Green'


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