Keels revisited - bilge, drop or long

by Stuart Warden
(Cape Town, South Africa)

I am rebuilding my open 19' day sailer, putting on a cabin and doing the insides, 2 bunks, gas stove etc.

The hull was originally a life boat from a tanker.

I am not sure if keels have been discussed on this forum, some other forums have had discussions on the pro's and con's of bilge,drop or long keels etc.- I guess all a matter of the wetted surface area ...and off course weight.

I am in Cape Town, South Africa and we do not have large tide swings (like the UK, for example) - our boats never touch bottoms unless on a hard or on trailers.

So the motivation for using twin bilge keels is not a consideration to deal with tides.

However, I find them fascinating and this could work on my 19'.

I used to have a long keel before but always felt it caused too much drag.

I want to turn this boat into a trailable boat so a deep keel is not really an option.

I estimate the keel ballast to be in the region of 400-500Kg, so does one split this up into two keels, or make a drop keel to the same weight - in both cases it would be easier trailable.

What are the views from readers to this problem?

Picture shows the first attempt to make a cement&steel keel about 12 years ago.

Eventually got it right, but I think too much surface area.

Thanks Stuart

Comments for Keels revisited - bilge, drop or long

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Sep 08, 2011
 What Keel?
by: Mike

Hi Stuart,

My own feelings are that bilge keels are the perfect solution for a trailer sailer.

On the trailer, the center of gravity can be kept as low as it is possible to go.

And the boat will be resting on points that were designed to take her weight rather than directly on the hull.

When sailing, I think there is a lot to be said for them.

If the bilge keels/plates are angled then as the boat heels, the windward keel will have less effect on leeway but the lee keel/plate will come more vertical thus becoming more effective.

And if you are concerned with directional stability, the keels/plates can be as long as you like.

Lifting keels, to my mind, come with too many possible problems, not least is that bloody great hole in the bottom of the boat.

Then there are the complications that come with the lifting mechanisms.

The ballast on the other hand, I would prefer to keep on the centreline.

This could be done with either internal ballast or with a stub keel on the centreline.

That way the bilge-keels could be just two simple plates, one either side.

Many years ago I had a ‘Silhouette’ which had flat metal plates either side as the bilge keels and a cast iron stub keel in the center as the main ballast.

I still think it was a perfect solution, both for sailing and for getting her on and off the trailer.




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