A keel is an experiment also. It won't be as efficient and may not bring the CLR back far enough. The centreboard has been shown to work efficiently. Even an Occy strap and a slight bed for the lee board should be enough to hold it in place with a pin higher to rotate around.
My concept of a tensioning pin was a bit different from Rudolf's, though his is probably simpler. I was envisaging a pin that went through a groove on the lee board to do everything. ie provide tension and to provide a fulcrum. I will be having bulkheads in the general area anyway so it is not a great deal more in weight and theoretically, the overall drag should be just about the same. ie the induced drag from efficient foils is about the same for the same lw resistance. It is one more thing to think about when coming into shallow water, but this is partly offset by shallow coming up a bit later.
I am certainly starting to get interested in the idea of reducing the loads on the rudders and possibly reduce overall draught. I would probably make the rudders the same strength as they are only about 15kg for the shaft as they are. It also provides braces and belt ofr cruising in places a long way from anywhere.
--- In harryproa@yahoogrou
>
> Hi,
> Yes I think it is different then larger rudder.
> I could feel the leeboard starting to work, the rudder is more efficient. That is I could turn the rudder a couple of degrees back (less rudder angle) and maintain course.
> Problem is to keep it on the guard.
> The owner may vote against another experiment he has to pay for and choose to have a keel instead.
>
> regards,
> Rudolf
>
>
> ----- Original Message -----
> From: Rob Denney
> To: harryproa@yahoogrou
> Sent: Thursday, October 15, 2009 3:49 PM
> Subject: Re: [harryproa] Re: sailing BD with leeboard
>
>
> G'day,
>
>
>
> Will be great to see how a leeboard works. Do you think the results will be different from increasing the immersed portion of the rudders?
>
>
> regards,
>
>
> rob
>
>
> On Thu, Oct 15, 2009 at 5:13 PM, Rudolf vd Brug <rpvdb@...> wrote:
>
>
>
> Your idea of a central pin under tension sounds good.
> If the profile of the leeboard starts under the horizontal lower guard the straight side would keep the board parallel to the centreline at all times. An upper guard should make it possible to have a central pin under tension.
> Maybe not that much tension, just keep it parallel to cl.
> Up and downhauls to keep it where you want it.
> I wouldn't bother with vertical adjustment, it's is enough complication as is.
>
> regards,
> Rudolf
>
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