Oughtred Lee Board Design

[Bobcat]

Oughtred has an unusual set up for lee boards. The board end is weighted with lead and there's a guard along the side of the hull. The only attachment to the boat is a line from the top of the lee board down at an angle into the boat. This line apparently hooks over the gunwale. There is no pivot.

Anyone used such a system?

[SJKaplan]

I built Iain's Macgregor CAnoe. I did not particularly care for this concept. I had brackets made by Springfield fan centerboard company. Bob Lavertue, the proprietor, told me that for a boat this size, you really only need one leeboard and you can use it on the windward side as well. I did not like that concept either and so he made two as shown in the photos in this link.

https://picasaweb.google.com/lh/sred...kwE&feat=email

Saul

[keyhavenpotterer]

Yes, I found it very difficult to use. Line cut through my leg when leeboard was working. Did not work off the wind when a fixed leeboard helps with stability a lot. Perhaps I did not stick with it long enough but I hated it. Pivoting leeboard a million times better.

brian

[skuthorp]

I too have a Macgregor canoe and sail with the original design single lee board. Mine is at attached to the keel by a line an SS fitting. Another forumite here, Sofala, has twin leeboards with through hull fittings. I have gotten quite used to my system and did not like the idea of penetrating the hull. She get's used as a rowboat or as yesterday, on very narrow streams with a single paddle. The water I sail in can be very thin indeed and at times it can be trailing an the sand almost out of the water completely. I guess it is a personal preference. I toyed with the idea of a drop in double dagger board arrangement but in shallow water that is not practical.

[Bobcat]

So how do you attach the lee board to the keel? Hook it up before the boat is in the water?

I don't see the problem with twin lee boards on pivots.

I am rigging a Puffin (10 foot Acorn) for sail by the way

[James McMullen]

I've used the leeboard with a line type, and on an Oughtred MacGregor sailing canoe, no less. I found it to be it no more or less utterly loathsome, vile and disappointing in practice than any other sort of leeboard.

Certainly I'd start with that. It will leave fewer scars for you to have to cover up than any sort of bracket or pivot mechanism for when you upgrade to a daggerboard or centerboard.

[andrewpatrol]

I'm currently building one of Iains Feather Prams with one of those boards too. What stops the board pivoting up?

[skuthorp]

I'm currently building one of Iains Feather Prams with one of those boards too. What stops the board pivoting up?

Just the pressure of the water. With the line system (SS loops on the keel, and a carabiner on the end of the leeboard line) it's easy to move the board back and forth as leeboard position and your own position have a great deal to do with how the Mac sails, points, steers and goes about. Ballast and it's placement makes a difference as well and my cockpit is 30cm longer aft than the plans to allow more comfort two up.

[wtarzia]

It seems to me that the method used on a Sea Pearl is very nice -- a glass boat but the method can be transferred to wood. Dual leeboards, asymmetric, the mount is hinged so that the now-windwardboard can wing-out if the sailor cannot raise it soon enough (does not snap something off). The positioning is solid, solving the problem of using a line and waterpressure. -- Wade (PS -- I deleted my dual capture-rail posting since I see this morning that the photo was not accessible for some reason probably due to the way Yahoogroups works).

[Ian McColgin]

On small boats, surprisingly small boards will work and you really can use just one, since you sail them pretty flat anyway. Below is pictured the board I use on the dink. The dink is not rigged for sailing and the board is really there because when rowing across or down wind it lets me track and rowing upwind against something serious I can tack up wind. It's easy to make progress a couple points off a near gale, compared to trying to row straight up it, but without the board the leeway is unacceptable and progress non-existant. This board really is big enough that it would serve should I ever put a modest lug sail on the dink. It secures from the inside with a simple wing nut. Hard to see on the outside but on either side of the pivot I fattened and flattened so the board lands with about 3" of leverage on either tack, above the pivot if the board is on the weather side. As the second pic shows, the board is secured up for towing with a little line.

[Lewisboater]

I have used a single pivoting leeboard on my little canoe/trimaran and it worked great. A bungee kept it down yet allowed it to pivot if it hit anything. I hung it on a single 3/4" SS bolt with plywood gussets glued where the hole went through the 1/4" plywood side.

[johngsandusky]

My BSD rig uses aluminum tube clamped on the rails to hang a single leeboard. Works fine, requires no modification to the boat.

[Bobcat]

I am tempted to make a leeboard set up like the one I had for a sailing canoe: a thwart that clamps onto the gunwales and from which the boards pivot.

It not require any modifications (damage) to the hull. When removed, all its weight would be gone and it would be a good test of using leeboards.

I had such a set up for a canoe. It seemed to work, but I did not sail the canoe much.

[James McMullen]

I got the hardware for to make one of those clamp-on canoe leeboard thingies, Bobcat. If you come up by Anacortes some day, I'll give it to you.
I won't be needing it.

[Bobcat]

I got the hardware for to make one of those clamp-on canoe leeboard thingies, Bobcat. If you come up by Anacortes some day, I'll give it to you.
I won't be needing it.

Thanks I may just do that

[johngsandusky]

My canoe sails well with it. The leeboard is long and narrow, and works well enough even trailing. I use a line to adjust it, straight down it really points her up.

[Bobcat]

My canoe sails well with it. The leeboard is long and narrow, and works well enough even trailing. I use a line to adjust it, straight down it really points her up.

How much of a hassle is it to swap sides as you tack?

[johngsandusky]

It stays on the same side. No hassle at all in a narrow canoe. By the time she heels far enough to make the leeboard ineffective on the windward side, you're already swimming.

[skuthorp]

My normal sailing ground is very shallow up to 2k off the beach and I have 2 different profiles of leeboard, one of which is like a fat teardrop to cope with this. It's not as effective of course especially in a chop. Being an old skiff sailor (Cherubs and Gwens) I could not resist attempting a trapeze. I can assure you with a cockpit cover you can get a decked Mac to skip sideways on it's leeboard, but a balanced lug rig is not really suitable. A once only experiment.

Quote Bobcat: "How much of a hassle is it to swap sides as you tack?"
I don't have much trouble with it but if you are doing a series of short tacks it can get tedious. If sailing two up it's the crew's job.

[Bobcat]

Random thought: what about a lee board that hooks over the rail? I have seen plans for such on other boats. Drop it in place---maybe one on each side ----

You would lose the fail safe that the board would kick up if it hits bottom. That is no different than a daggerboard. You would also not be able to pivot up the weather board.

The advantages would be that you don't modify the hull. When you want to row the boat, there's no weight from the boards because they are removed completely.

[wtarzia]

So where do we go for a profile for an asymmetric leeboard? Sure it is not so simple a flat leeward surface and a curved ww one? -- Wade

[Lewisboater]

Look at the one above in post #11...rounded leading edge and tapered trailing...that is all you need. A fully profiled NACA shape would only get you 1 or 2 degrees closer if at all on a leeboard. You could do the same with another few square inches of board in the water. Your sail shape and rig style will have more effect than the shape of the board will.

[Mike V.]

Random thought: what about a lee board that hooks over the rail? I have seen plans for such on other boats. Drop it in place---maybe one on each side ----

You would lose the fail safe that the board would kick up if it hits bottom. That is no different than a daggerboard. You would also not be able to pivot up the weather board.

The advantages would be that you don't modify the hull. When you want to row the boat, there's no weight from the boards because they are removed completely.

The Bolger Junebug specifies this exact type of leeboard attachment. I built it to plans and found it to be useless. The first time the tip of the board touched a rock the attachment prongs of the board snapped right off. I modified the board to pivot and have been much happier with that arrangement. Jim Michalak uses this style of leeboard attachment in many of his designs.

[Bobcat]

The Bolger Junebug specifies this exact type of leeboard attachment. I built it to plans and found it to be useless. The first time the tip of the board touched a rock the attachment prongs of the board snapped right off. I modified the board to pivot and have been much happier with that arrangement. Jim Michalak uses this style of leeboard attachment in many of his designs.

Thanks good to know.

[gilberj]

I sail with leeboards now on Whimbrel, (LFH Herreshoff Meadowlark) this is a different sort of thing being much larger.......there are advantages for me and disadvantages, but they are pretty much right for this boat.
This thread is about smaller boats. As a teenager I fitted an old set of canoe leeboards and sail onto a small double ended skiff and sailed hundreds of miles all over the Muskoka Lakes in Ontario over a period of perhaps 5 years. As far as I am concerned they worked fine and were little nuisance. In this case I seldom raised the windward board, as it was not really a problem.... except when approaching the shore when I raised both. I like the fact the unit was added on to the hull rather than permanently fitted.
The alternative of course is to fit either a centre-board or dagger-board, possibly even off-centre-boards. These do not need as much tending when sailing and are possibly a little more efficient for the simple reason they do not penetrate the waters surface like the lee-board(the lee-board should/can be shaped to maximize lift on the one tack) The case though is at least somewhat in the way and hard to maintain.
For me leeboards have their place, not just as a curiosity
With Whimbrel I would not consider changing her to a centre-board or dagger-board. I like the relatively unencumbered space in the cabin.

[DavePont]

Jim Michalak uses this style of leeboard attachment in many of his designs.

I posted the following a while back on another thread () could not find it to link to so re-post) - my take on the Michalak is a setup I have found works very well.

Below is the new leeboard. Shaped to NACA 0012. The setup is in the "Jim Michalak" style, here is a link to his article: http://members.fortunecity.com/duckw...0615/index.htm The board pivots on a galvanised bolt through the side of the hull. On the left of the image below you can see one end of a 40mm wide strip of ply on the side of the hull, which the leeboard rests against as a spacer. Inside the hull in the same position is a length of 20 by 40mm wood to spread the load. This and an identical strip on the other side of the hull are the runners/supports for my forward seat. The upper end of the board locks in under the 'outwale' above when it rotates upright. Internal bracing runs from inwale to inwale and down to the back edge of the seat. The white star shaped 'knob' is a piece of hardwood with galvanised nut recessed and glued into to it so I can remove and adjust leeboard tension without tools.


In the following close-up you can see better how the board can rotate under the 'outwale. This setup resists side forces equally both ways, simple and effective.



Dave P

[Lewisboater]

I like the board but... very interesting scroll work...decals or templates?

[Breakaway]

Internal bracing runs from inwale to inwale and down to the back edge of the seat.

Hi Dave. Thanks for the post. I did not understand the part about the internal bracing. Would you mind reiterating?

Thanks
Kevin

[DavePont]

very interesting scroll work...decals or templates?

This is a trick I saw on the CLC forum: the entire outside of the hull is covered with a layer of fabric (cotton / polyester) wet out with epoxy. Light fibreglass cloth goes over that invisibly. The end result is very eye-catching. Your local fabric store gives you lots of choices, I went for a local (NZ) kowhaiwhai pattern.
Dave

[DavePont]

I did not understand the part about the internal bracing. Would you mind reiterating? Kevin

Hi Kevin, here is another pic inside the boat. You can see my seat resting on the runner at upper right of the picture. The galv coach bolt for the leeboard goes through that somewhere below the back edge of the seat. My 4mm ply hull was flexing a fair bit so I added the small wood triangular brace between inwale and seat back, it still flexed so I added the 4mm ply brace from inwale to inwale. Now it does not move.

[Breakaway]

Now I've got it. Cool. Thanks

Kevin

[Wooden Boat Fittings]

I am tempted to make a leeboard set up like the one I had for a sailing canoe: a thwart that clamps onto the gunwales and from which the boards pivot.

It not require any modifications (damage) to the hull. When removed, all its weight would be gone and it would be a good test of using leeboards.

I had such a set up for a canoe. It seemed to work, but I did not sail the canoe much.

I have a similar setup for my PBK27 kayak. She has canvas hull and side-decks which of course I didn't want touched. Blandford's solution was to clamp a 1" x 1" hardwood bar across the cockpit using U-bolts under the coaming on each side. Then lee-boards attach to each end of the bar with an embedded axial bolt and a wing-nut. Wingnut friction keeps the boards down, but if they hit the bottom in shallow water they simply swing up out of the way. I leave both boards down when sailing, and I almost never go out without the sailing gear (all of which stows under the foredeck when not wanted.)

Mike