Catamaran Daggerboards and Keels – Woods Interview # 9

I am with Richard Woods, and we are talking about catamarans. He’s a legendary catamaran designer and experienced catamaran sailor of many different designs. This is one of several interviews we’re having on different topics. Today, we’re talking about daggerboards versus keels. Richard will tell us a little bit about how daggerboards work, how keels work, and what some of the benefits of each are.

For more from Richard Woods, please go to his website.

Richard, can you start off with what dagger boards and keels do for a boat?

There’s the three basic ways of preventing leeway, which is what you’re going to be doing with a multihull. On a monohull you’ve got the keel. Essentially, it’s for stability to balance the heeling, to stop the boat heeling too much. You don’t have that as a problem on a multihull. You are just trying to stop leeway.

You can do it either with using the hull shape, which would be like a Catalac or Wharram catamaran. Then the next would be to have keels. The third would be to have daggerboards.

Catana 39 Underbody – No keel but daggerboards

You could essentially say that a catamaran with keels is a bit like a long-keel monohull, and the daggerboard catamaran is a fin keel monohull in more terms. I think we all know and all agree that the best sailing boats are going to be the one with fin keels. Then progressively a long-keel boat or keel or one with low aspect-ratio keels on the catamaran, that would be the next best. Then the one relying just on hull shape, whether it’s a test barge or a Catalac is going to be the the least good.


There’s two things on that. One is that the daggerboard prevents leeway better, but also prevention of or reduction of pitching, increasing potential top speed. You want to have buoyancy at the ends of the boat and not in the middle. You imagine a diamond shape sailing to windward, and it pitches up and down, up and down, and you end up hobby-horsing. Whereas a boat with fuller ends isn’t going to do that. Unfortunately, the thing with their keels, is that the buoyancy is more in the middle of the boat.

Woods 36 Vardo with Keels

So there’s the two factors: one is the the sea kindliness of having daggerboards, and the other is the better performance.

A daggerboarded boat is always better, but it does have some disadvantages. The main one is that if you want to beach your boat or dry it out. To me, that’s always a major advantage of a multihull. You got to be able to have lifting rudders, and essentially, you don’t want your propeller to be the deepest part of the boat, or if you’ve got an inboard engine.

The daggerboarded boats work really well when you’ve got outboard engines and when you’ve got tiller steering, because it makes it easier to get the rudders. It is still possible on bigger boats and you can also have a bit of a compromise of having a small keel, and then the daggerboard. Or you can have like your boat was, which had daggerboards in the lead hull, so you didn’t need to lift the rudders. The rudders are still higher than the bottom of the keel.

Woods 40 Meander with Daggerboards Beached

Although there’s a lot of places in the world where you don’t have to beach the boat, the most obvious to say: the Great Lakes in North America, Florida, the Bahamas, most of the Caribbean in fact, you don’t have to. The Mediterranean. They don’t have tides and so you’re not in the beach.

I’ll just show you this. I’m just going to turn the camera around a bit now. As you can see, this is our house now. In fact, it’s low water and we have about an 18-foot tidal rise, so that’s more than you. It actually is neat, so it goes up quite a bit further. But we are used to drying out for six hours a day, every day when we moor our boats. So for us, it’s much more important to have good protection for the bottom of the boat.

If you’re sailing in Florida and then you sail up to say, Cape Maine, you suddenly get to the box and you get this 10, 12-foot tide, and you do want to go around, either deliberately or what not. With daggerboarded boats, you’ve got to think about a lot more when you’re beaching a boat.

The interior room, you might think that was a problem. But usually you can make the daggerboard, say, fit around the side of a heads compartment, or the galley worktop, or something like that, so it’s never really a problem. You can have the dagger board on the inside or the outside of the hull, it doesn’t seem to make much of a problem either.

Catana 39 Daggerboard

But the other thing is that the daggerboards are more expensive to make because you’ve got to make the daggerboard case, which is in effect, same as making a keel. Then the daggerboard and then the controls for the daggerboard, so that all adds to cost and complication.

And there’s definitely a learning curve to knowing how to use the daggerboard effectively, and have that experience. So are they less of a beginner kind of attribute on a catamaran and more of a somebody who’s been sailing for a while?

Yes. There’s no point really, in having daggerboards if you’re not going to use them. Essentially, that means having them in simplest, both down sailing to windward, and then lift the leeboard when you’re reaching, and lift both when you’re sailing downwind. That’s the normal.

But you can have the position of, if you’re sailing in big seas, especially big quartering sea downwind, the tail wags the dog. In other words, the rudder steers, and it’s not actually doing anything, because there’s no hull in the water. Then, it makes it a lot easier having the daggerboards both half down.

Perry 52 Catamaran Reaching with Leeboard Up

So yes, you learn quite quickly how your boat behaves according to whether the daggerboards are up or down.

The other thing that I found, is that a lot of people, when they break a daggerboard, it tends to be the lead daggerboard that breaks. When you’re sailing, that’s the side that gets powered up when you’re pushing down on being hit by a wave, and pushing sideways tends to break the daggerboard.

Of course the other thing is, it’s quite a good ultimate echo sounder. We have never actually broken a daggerboard, on any boat, I don’t think. When we were, this is a good excuse because it was an unmarked reef, but we were sailing off Nicaragua, and we were sailing at eight knots. We hit a reef with the daggerboard and the boat stopped dead. In fact, my wife fell over. It was driving a car at 10 miles an hour into a wall, sort of effect, and once we sorted ourselves out, and we lifted the daggerboard, we lost about the trailing edge, about a foot by four inches being totally destroyed. We had a mill u-volt, a 5/16th u-volt, as an up haul, and that was bent completely flat by the force of the boat stopping.

I guess it was a sacrificial item!

We still sailed.

Right. That’s what I’m thinking. Rather than hitting the reef with your boat, you hit it with something sacrificial. They can be expensive to replace, but…

Yes. We didn’t hit it with the boat, no. We hit it with something that we could carry on for another three months before we actually had it taken out of the boat and repaired.

Gemini 105 Centerboard Repair

Of course, that’s always something. If you can take the broken bit to the mechanic, or to the boat yard, that’s always better than doing it the other way around. Usually, you can carry on sailing with one daggerboard or two half-daggerboards, whatever, but it is quite a common problem.

As I say, if you’ve got a conventional inboard engine with fixed rudders, there are quite a lot of multihulls around, even here, but they’re treated like monohulls. You can’t, for example, go to the Scilly Isles and go to Hawaii, and Green Bay, which is a wonderful place to spend a lifetime, really. It’s the nearest the equivalent of going into the Bahamas. But you can’t do that if you’ve got a boat you can’t dry out.

I guess that’s why multihulls became so much more popular in the UK before other places.

Everything in design, it’s always interconnected. Going back to the comfort, and the rolling. If you look at the Scilly Isles, which are 30 miles off the Southwest corner of England, sort of like saying you’re going out of Miami, and there’s the Bahamas. It’s not quite that far, but it’s pretty near the same as going to Bimini.

There’s a whole stack of islands, but the pilot guide says there is no safe anchorage, because it was written by a monohull sailor. We’ve been and they say, “You know, if you go into this anchorage, then you’re going to be as protected as you can be.” We’ve been into those anchorages, and they’ve been horrible, because you’re open to when the tide’s in. You’re open to the ocean because when they’re out, it’s out in the Atlantic. When you can dry out, you go onto these lovely sandy beaches, and you can dry out and you’re safe then.

Well that’s cool. So thank you Richard, that was fascinating on daggerboards and keels.

Diane Selkirk

By Diane Selkirk

I love to travel and have spent the past seven years sailing with my family aboard our 40 Woods Meander catamaran - traveling from B.C.'s north coast, to the west coast of the US, Mexico, the South Pacific, Australia, New Zealand, South East Asia, across the Indian Ocean to South Africa and on to St Helena, South America, the Caribbean and Central America.

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