Leeboard shape and shoal waters

[David Geiss]

Hi, this is perhaps directed to the canoe sailors and leeboard fans among us.I generally use a higher aspect single leeboard on my open canoes.

Last week had the pleasure of sailing in and about Asseteague and Chincoteague Islands in coastal VA. Particularly fond of Lil Oyster and Big Oyster Bays, also area around Asseteague Point entering Tom's Cove (one big ass body of water!).

I encountered some rather shallow areas and a hard bottom.......got me thinking that I'd like to explore having a teardrop shaped Dutch styled leeboard, something along the lines proposed by Todd on page 154 of his Canoe Rig. I understand that the max chord length might make such a board perform better in lighter winds as opposed to heavy breezes.

I mostly day trip and tour so race performance is not necessarily what I am after; just the ability to keep a larger immersed surface in the water, and not too far aft, when I 'm skimming along water on the order of 10" in depth....

Has anyone played around with such teardrop shaped leeboards?
Comments?

All input appreciated.

Best,
David

[Thorne]

My friends have used them on small open boats with great success, but I can't say they've tried comparisons with high-aspect narrower boards.

[David Geiss]

Nice vessel, nice hat! Thanks for posting....always been fond of prams!
Is that a board as well on your starboard gunwale?
David

[Thorne]

That's my friend Tony in his Piccup Pram, with leeboards on both sides. He's painted it since the photo above and reduced the size of the rudder head and blade to more a standard configuration.

Pic from yesterday on Big Lagoon -

[David Geiss]

Tons more class and panache than an Opti!

[johngsandusky]

My canoe sails with the usual high aspect leeboard from BSD. In very shallow water I raise the board to almost the hull depth. She sails fine like that. Probably doesn't point as high, must use a little rudder for balance, but marsh-sailing is different then racing. I like sailing so close over the bottom that I scare crabs. My canoe has good directional stabilty anyway, but I'd try tinkering with your existing rig before building a new leeboard. Can you move the sail center aft to compensate?

[David Geiss]

Good insights John, thanks. My leeboard thwart is semi permanent and dialed in for lateen and smaller heavy weather sprit rig. Mast step perm as well.
The boards I have are all pretty high aspect. I think I will create a teardrop shaped one, tinker around and perhaps report back.
In 8" of water I have to raise the board so much that it does little for lateral resistance and what it does provide is so far aft as to really throw off helm balance.
BTW, I steer exclusively with a paddle to leeward side.
Cheers,
David

[Nicholas Scheuer]

I like relatively high-aspect assymetric foil leeboards. However, Dutch-style teardrop makes a lot of sense in your case.

I'd make a side elevation scale drawing of your canow with a teardrop board swept aft for use in shallow water. Then I'd add more curvature to the forward edge so you increase immersed area without pivoting the board more vertical. Then I'd straigfhten out the aft edge of the teardrop profile because it's already high and dry, so why carry the weight. Lastly, I'd take a paper cutout of the modified teardropshape arrived at above and using a pencil point or pin at the pivot point, rotate the board down for use in deeper water. If you like the look of that, make the board that way.

Increasing the leeboard's area along the forward edge with a bit more curvature will move the CLP less far aft when the board is angled aft for shallow water than if the forward cedge is relatively strainght.

The rounded tip of a Dutch style-leeboard, given a round leading edge, tapered trailing edge, and blended bottom edge will move through the water at any angle much more nicely than a board with a square tip optimised for use in a vertical position.

Moby Nick

Moby Nick

[David Geiss]

Hey Moby, wow, there's a lot there! Greatly appreciated and you're an example of what makes this Forum so useful and informative.......I understand what you are proposing about the aft edge...need to work out on paper/matte board what you are proposing to the fore portion.
Best,
David

[wtarzia]

I was looking at a lovely Dutch boat at the Mariner's Museum at Newport News with an overpoweringly huge teardrop board. I wonder what kind of water it was sailing in? Its planform seemed symetrical. --Wade

[aprophet]

I use a small kick up lee board on my outboard driven canoe that has an outboard bracket off to one side I use the lee board partly as an offsetting bit of weight and partly for the added stability. I will try to get piccys up in the next day or so

[skuthorp]

I sail mostly on a shallow bay where the water goes out up to a mile in places over sand and mud. Not a place to walk home. The canoe sails in a few inches of water often as I race the tide home. I use a Dutch style tear drop style board there and a higher aspect board in deep water trips. Teardrop board is not so successful in broken water though. My leeboards are not fixed though I have thought of a removeable double dagger board casing before.

[David Geiss]

Hi skuthorp.....what type of vessel and how are you affixing the leeboards to the vessel?
Thanks for posting!
David

[skuthorp]

G'day David, It's a 15'7" Ian Outred Macgreggor decked canoe with a balanced lug rig. I sail it, row it, paddle it single and double and it makes a great surf boat with the canvas cockpit cover on as long as you stay away from big white water. Leeboard, only one at time, is connected to the keelson by a line and shackle and I move it over as required. That way I can steer with it by moving back and forth or do without on a run or under paddle power up a creek. I do not fancy messing up her lines with a permanent fitting and was concerned with pressure on the hull if stuck in mud. (It happens).






This is a very good thread on sailing canoes currently active.
http://forum.woodenboat.com/showthre...-sailing-canoe

[David Geiss]

Lovely looking Ougtred sail canoe...phenom looking finish. I have always been curious about that method of leeboard attachment; recall reading about it in John Bull's materials. Is there sufficient pressure on say a beam reach to keep the board pinned against the leeward side of the vessel?

Best,
David

[sofala]

Hi David,
I too sail a Macgregor canoe but I've opted for two swinging leeboards. It is simply a matter of lowering and raising them as one tacks. I tried the single leeboard attached to the keelson with a line. I found that it kept popping out and wouldn't stay against the leeward side of the boat. Michael Storer gave me some tips about strengthening the hull to take the pivots and it has worked really well. I also allowed for the fitting of outriggers for those days when I wanted a bit more security. However, Skuthorp is a very experienced Macgregor sailer and has probably mastered the technique of sailing with his leeboard on a line. I can send pictures if you want. I can remember how to post on pics on the forum.

BTW Skuthorp we have another crew member due within a week. Hope to catch up at the next Goolwa Wooden Boat Festival.
Cheers

[Songololo]

I'm busy with the leeboard and rudder for my We Rob canoe (a smaller version of the MacGregor) and have some questions regarding the leeboard. Rather than start a new thread, I thought I'd include it here...

The leeboard will be held in place (at least initially) as designed, with the keelson line. The board is being constructed as per the plans i.e. teardrop shape, asymmetrical with the flat side on the outside and the foil shape on the inside.

Some questions:
- How big and what shape should the bearing surface be at the top of the board on the foil shaped side?
- What maximum angle does the board typically get set at? The ideal (start) angle on the plan is shown as approx 17 degrees. I was thinking 45 degrees as a maximum.

The reason I ask about the shape and size of the bearing surface i.e. the part of the board that will rest against the hull's leeboard bearer, is that when the board is rotated up to say 45 degrees, then it would seem as though a large section running down the aft of the board at an angle, needs to be flat so that the board cannot rotate on the rounded foil surface. Having a flat surface, the size of say a 4-5in arc drawn from the line hole, does not seem to provide a large enough flat surface at when the leeboard is angled at 45 degrees.

[skuthorp]

I can't answer most of that as I'm 1500 kilometers from my Mac at present on a driving holiday. Actualy I doubt that I was that scientific. But rather than having a strip on the hull side to bear against I have the bearer attatched to the leeboard in the form of a shallow arc, and that part of the leeboard is flat being mostly above water. The other reason is that I often use the leeboard to steer with and move it about quite a lot. Incidentally with my method of attachment you have to strengthen the designed cockpit combing for about 12-18 inches to cope with the strain. I am an old skiff sailer and push the mack way beyond her comfort zone so I occasionally get wet. The leeboards efficiency decreases as the ange of list increases to the popint that the hull can slide to windward and dump you in the drink if you are 'hanging out'. I built a bent leeboard for this purpose, it works but it's more messing about having two in the boat to get tangled. I have never liked the pedal steering and have a continuous line set up with a couple of jam cleats. BTW. the bright finished Mac is not mine, just there for example. Mine is painted yellow and showing her age and use in salt water. I plan to strip her back to bare wood this winter and start again.

[akitchen]

G'day David, It's a 15'7" Ian Outred Macgreggor decked canoe with a balanced lug rig. I sail it, row it, paddle it single and double and it makes a great surf boat with the canvas cockpit cover on as long as you stay away from big white water. Leeboard, only one at time, is connected to the keelson by a line and shackle and I move it over as required. That way I can steer with it by moving back and forth or do without on a run or under paddle power up a creek. I do not fancy messing up her lines with a permanent fitting and was concerned with pressure on the hull if stuck in mud. (It happens).






This is a very good thread on sailing canoes currently active.
http://forum.woodenboat.com/showthre...-sailing-canoe

Browsing through the forum for ideas, with the goal of modifying the leeboard attachment on my MacGregor canoe,
I was surprised to see the above picture of my canoe in my garage workshop. What should I make of this?

Andrew

[sailnstink]

I built the Storer rig and lazied out and use a sunfish daggerboard for the leeboard instead of building one, turned out to be insufficient. The original Old Town lee boards were ovalish inline with what you are thinking about.

[Bram V]

Browsing through the forum for ideas, with the goal of modifying the leeboard attachment on my MacGregor canoe,
I was surprised to see the above picture of my canoe in my garage workshop. What should I make of this?

Andrew

The post just above yours. It was a picture to show the type, not the exact boat.

That, or someone else uses the boat while you're not, and you simply never noticed. Cat burglary is not the most useful way of obtaining boats however.

Very pretty boat by the way.

[skuthorp]

akitchen, I just googled macgregor for an example and your pic came up. I hope you are not offended. Mine hasn't looked that good for a very long time, if ever! Yours is quite stunning. I have lengthened my cockpit aft to make her more comfortable for 2. She carries a single balanced lug sail but in retrospect a yawl rig would have been much better. I have been sailing mine for about 12 years and it shows.

[akitchen]

No offense taken. I was just a bit confused, that's all. Mine hasn't been on the water this year; I have too
many boats: the MacGregor, an Oughtred JII Yawl, and a couple of double paddle canoes. The canoes and
the yawl have had all the action this year. I do like the yawl rig (on the Mac and the JII), it makes reefing
and just plain hanging out, say for a lunch break, such a breeze (pun intended). :-)

[David Geiss]

I have finally arrived at a shape for my teardrop style.......sailing along some marshes yesterday made me realize I need to manifest it in wood...NOW! Will post a pic of the template up against the mount pivot. Great article on the larger Dutch leeboarders in current WB mag.
I maintain that leeboards make a lot of sense..perhaps not for everyone.

Best, D

[Plumbtex]

Here's a pic showing the leeboard shape I used on my Bolger Light Schooner. Before going to this shape I made a long high aspect board - I hated it. This board made all the difference it was a much nicer boat to sail after the switch. The boat was originally equipped with an offset dagger board but that was totally unsuitable for the shallow Texas bays.
[IMG][/IMG]

[David Geiss]

That's a nice looking rig. Do you use a single leeboard to starboard?
Best, David

[Plumbtex]

Yes, it's a single board to starboard. I attached it on a shaft running across the deck in wood bearings so that the boat could easily be returned to its dagger board configuration if desired. It's sailed the Tx 200 twice, first with me and again the next year with the new owner.

[gilberj]

I had a double ended skiff as a youth which I rigged for sailing. I started by using a regular canoe paddle as a leeboard, and to steer. To turn downwind I bring the paddle aft, as I slack the sheet, and to round up or tack I stick it forward. it worked quite well but I was young and ripe for adventure. With this set-up I could not hike out when the wind piped up. I found some canoe leeboards which I modified to fit my boat, and the paddle became a steering sweep.
There was one time I went out on a brisk day. This was fine till the wind pretty much doubled. I could not get to windward at all, and home was to windward, so I had to run off across the lake and landed on an island till the squall blw itself out and then sailed home, to be grounded.

[Paddleplus]

this is an interesting thread. i sail a 15 ft. stripper and a 17 ft. Old Town canoe. i have 3 sets of leeboards for varying conditions. One is 54 inches long for deep water and racing, one is 36 inches long for all around sailing, and the 3rd looks like a pizza board which is good for shallow water. i usually use only one leeboard which is mounted on the left side of the canoe. I'm left handed so that works for me. the pizza board type leeboards are B.N. Morris leeboards and have an interesting construction feature, there's an inside brass ferral fiiting that acts like a bearing block. i made my other leeboards per the ACA sailing proceedures, they are airfoiled like an airplane wing. I'm convinced that for sailing in shoal water, all that's needed is to have a tip of the leeboard in the water but like the other person said it's hard to sail too close to the wind but it's good for gunk holing around. I sail on the Chesapeake Bay's tributaries and am a poor speller.