Subject: Re: [harryproa] Re: BD with tandem keel
From: "Rudolf vd Brug" <rpvdb@freeler.nl>
Date: 1/4/2010, 4:24 AM
To:
Reply-to:
harryproa@yahoogroups.com.au

 

Hi Robert,
 
The difference is that without the keel (or leeboard) we could get it sailing only when headed downwind.
With keel sheeting in carefully at 90deg to the wind works most of the time. If the boat is reversing a bit and you pull the sheet it will head up.
So it has to have no speed, or forward speed.
Also sailing hard on the wind was impossible without the keel.
So I suppose there is less load on the rudder, but we still have these big rudder angles on both rudders.
regards,
Rudolf
----- Original Message -----
From: robert
To: harryproa@yahoogroups.com.au
Sent: Monday, January 04, 2010 3:02 AM
Subject: [harryproa] Re: BD with tandem keel

 

Hi Rudolf,
I wonder if the loading on the aft rudder is NOW significantly less than it used to be. Do you notice any difference?
regards,
Robert
--- In harryproa@yahoogroups.com.au, "Rudolf vd Brug" <rpvdb@...> wrote:
>
> Hi,
>
> It has been some time since we put BD ashore next to our house.
> That was December 4th, earlier that week we sailed her with the tandem keel fitted.
> The keel was fitted using threaded rods in epoxy in the keel fins. We just drilled holes in the bottom of the hull,
> put the rods through them and floor timbers on the inside to distribute the loads.
> Plenty of sealant obviously. It took two hours including hoisting and relaunching.
> As usual I forgot the camera so no photos, sorry.
>
> Sailing with the keel fitted showed that we could get going with the wind at 90 deg. as with the leeboard.
> It was obvious though the leeboard was more effective, we could steer close to the wind but needed more rudder angle to keep control.
> Second test sail was with one of the old rudders fitted additional to the new ones.
> I wanted to see if this would cause a significant difference.
> We had the new rudders out of the water, so just one old rudder and the tandem keel. Sheeted in carefully and got going easily.
> When at speed no noticeable rudder angle, speed up to 12.5 knots could have gone faster but we didin't seek speed.
> Control with the old rudder was very precise, what I find to be missing with the new ones.
> After shunting returned with the new rudders, high rudder angles 11 knots max and we could feel the power that couldn't be put to use.
>
> It seems the keel works, although the leeboard was more effective. The leeboard would need more experimenting to come up with a good
> way of keeping at the right angle and prevent it from kiting. I think the leeboard would have to be handled at every shunt. That is one of the reasons the owner likes the keel better.
> Hopefully carefull finishing of the rudder blades will lead to smaller angles when sailing.
>
> regards,
> Rudolf
>

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