catamaran performance

Daggerboards

Go to wind

The ability of a cat to go to wind has a profound effect on not just performance, but everyone onboard.

Beating backwards and forwards while making little progress to destination, especially in strong conditions, loses its fun quickly. 

When building a cat or shopping for a new one, the daggerboard rarely gets much attention. It was the case for me. When I built, I never gave it a lot of thought. It was only after a year of sailing my boat that I came to realise just how import the ability to go to wind is.

Most cats go to wind poorly, so much so it’s become a cliche, but it doesn’t have to be that way. What is missing is area. Cats simply don’t have sufficient keel area, as simple as that. And splitting what area they have into two – also detracts from their ability to point high.

If you correct that problem, then a cat goes to wind much better than a keel yacht. They don’t lay down and spill the wind (and make you walk on the walls). They have 2 long slender hulls that slide through the water better than one fat one. And, they aren’t carrying tonnes of lead around the ocean (which makes no sense).

Once I corrected the problem, I ran circles around everything, even racing keel yachts. I never looked back.

Performance and space

racing catamaran

One large board – is better than two

Combining two boards into one doubles the chord, reducing induced drag. The larger surface area means the board operates at lower angles of attack. Tip losses around the bottom of the board add significantly to total drag. Having one board cuts that in half.

The result, less drag, more power/thrust, less side slip and much better steering.

Not happy with my windward performance, I went back to my boat shed and built a solution.

Once I finished my cat was a different boat, completely. It went upwind like a tractor and at angles I’d never experienced, and fast.

But, I could also go upwind slowly and when the weather turns foul, this ability is important.

Another side effect of the change was the steering suddenly was light. Even in the heaviest of conditions, it never loaded up like before.

Building one daggerboard and case is quicker than building two. Having only one board leaves the other hull free—more room in the galley.

25 years of flexing and no signs of wear

single daggerboard

Watch my video

Shave days off windward passages

With its large chord, deep draught and glass-smooth white surface, this board cuts through the water like a knife.

Raising and lowering the board when running downwind – makes no measurable difference to speed. 

TE30 – a smaller version to suit 30ft catamarans

A smaller version of the TE40 board is now available to suit 30ft cats.  Click the buttons above or below to learn more.

Build with standard materials

– Plywood
– E-glass
– Epoxy
– Paint

These non-exotic materials are the most economical and also the best for the job.

There’s nothing low-tech about plywood, e-glass and epoxy. Flexing continuously for years is what they do best.

Engineered for your boat

Two plans are available with all you need to make your own board. Suitable for 30ft and 40ft cruising and racing cats.

Tim Weston Boats

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