Subject: Re: [harryproa] Leeboards?
From: "Rudolf vd Brug" <rpvdb@freeler.nl>
Date: 11/4/2008, 3:21 PM
To:
Reply-to:
harryproa@yahoogroups.com.au

Hi,
 
Usually  a leeboard is supported by a piece of wood a bit above the waterline to keep it vertical or whatever angle the designer wants it to.
Also this support keeps it away from the hull. When moored or docked the leeboard can be pulled up above the support which becomes a rubbing strake now protecting the hull.
A well shaped leeboard will lie against the support troublefree. I must add I am talking old fashioned one way leeboards, but I am confident it can be done for symetric profiles too.
 
I am of the opinion that having just a leeboard is simple, putting it in a pivoting case and pulling it up and down is a sure way of complicating things.
These things were invented for shallow waters, when the water is too shallow you just pull them up. Also consider that when sailing in such shallow waters it wouldn't be wise to maintain high speed.
Having two rudders in the water should in these circumstances enable you to keep going, slowly.
 
Complexity of having a leeboardis a trade off with having less complex rudders. A leeboard should be very simple or it looses its atractivity.
It does need two lines to pull it up and down (fore and aft) to the desired angle. They would probably need need handling when shunting. If smaller rudders would not need turning 180 this might be an acceptable effort.
 
Rudders of Blind Date are drawing 2 m and 0.5 m wide, and I feel they should be partially retracted when sailing at 8 or 10 + knots.
Front rudder doesn't seem to be doing much when down and pointing straight forward.
 
A leeboard on the ww side of the hull would require a complicated construction to keep it next to the hull or the pivot just above the waterline.
That would have the leeboard always touching the water if it were up or down.
 
Rudolf
 
 
 
 
 
----- Original Message -----
From: George Kuck
To: harryproa@yahoogroups.com.au
Sent: Tuesday, November 04, 2008 1:54 AM
Subject: Re: [harryproa] Leeboards?

Hello,
 
Yes, a few other reasons not to use leeboard.  It would get in way when docking or raft up to other boats, the aesthetics and clean lines of boat, complicates shunting and may not work if short tacking (depends on design).
 
Another option you may want to consider would be a pivoting symmetric centerboard/leeboard or whatever you want to call it mounted on windward side of lee hull.  It would be out of way under center catwalk.  In this location it would be easier to get to to control then if on lee side of lee hull.  Whatever you use should have control lines near steering station so a solo sailer can control it.
 
George  

--- On Mon, 11/3/08, Gardner Pomper <gardner@networknow.org> wrote:
From: Gardner Pomper <gardner@networknow.org>
Subject: Re: [harryproa] Leeboards?
To: harryproa@yahoogroups.com.au
Date: Monday, November 3, 2008, 7:14 PM

Well, I plan on having Rob do the design for me too, but one of the things I really like about this forum is how people explore different options. All designs are trade offs, and I am not yet convinced that a very complicated all in one rudder solution is actually simpler that simple rudders and leeboard, which is why I am looking for feedback.
 
Are there other reasons, besides building the case, that you don't like the idea of leeboards?
 
- Gardner

 
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