Basic Leeboard Info?

[Guest]

I know little to nothing about leeboards. The closest I have come is downwind sailing while holding a semi vertical paddle blade rudder. That is quite unnecessarily tiring. My leeboard questions are novice elementary.

Where, fore and aft, on the hull is the lee board best located? I presume by necessity somewhere within reach of the stern seat or, if solo, the center seat, if only for manipulation access? What about in a tandem, close to the stern paddler, or as far forward amidships as still within reach?

How close to the hull? I need to drill new thumb button adjustment holes in a crossbar for the slide in receiver. Should the lee board be positioned as close to the hull as possible? Or a few inches out, provided it is still out of paddle stroke range?

P1220435 by Mike McCrea, on Flickr

How deep into the water should the leeboard reach? Any of the leeboard above water is useless, and I expect deeper is better, within reason. Is extended below the hull beneficial, as with the propeller wash and water dynamics on a motor?

Lee board use is probably a tiny paddlesport niche within a niche. I Googled Everything you ever wanted to know about lee boards but were afraid to ask, and while it was a fun read, and I did learn some new positions, none of them had anything to do with where to locate a lee board.

 

[yellowcanoe]

You have met your match in theory of leeboards. I am an observer and a picker apart of leeboards whose craft wind upside down in Moose Pond, I never paid much attention to where the dang thing was on the canoe but more that it was . While in a little canoe as a rescue person I had to disassemble the leeboard and the rudder and the sail while trying to keep the four letter words contained in the middle of Moose Pond.. Which is a 7 by 1 mile lake, In local lingo a pond. Don't ask the difference between pond and lake.

Paddlers typically slouch aft of center but want to be able to reach to flip up the leeboard when coming into shore as it makes an unpleasant landing if left down. Most of them I have seem are not as deep as yours. The WCHA sailors can give you some dimensions. Benson Gray is our chief sailing nerd at Maine Canoe Symposium and is a member of that board. www.wcha.org. Its a polite forum.. He knows it and can do it.

I can sail a Sunfish and a small day sailer. Both are centerboarded and the board is close to the midpoint. Beyond that I am clueless.
I am not asking abut the positions you learned... my imagination runneth away.

The vector analysis is crude but to avoid the thing from turning I would try to guess where the center of rotation is.. You want to temper the amount of sideslip and not generate a turn..

OK canoe designers lets go..

 

[Bothwell Voyageur]

just in front of the centre of effort of the sail as far as I can remember. There is a neat little book by the late John Bull of the UK open canoe sailing group that is worth seeking out. Haven't canoe sailed in a long time but our leeboard was about four and half feet long and a foot wide and had a hydrofoil profile.

 

[Glenn MacGrady]

ACA Sailing Canoe Instructions - DIY

Also: ACA National Sailing Committee site

 

[stripperguy]

If you're using a sail with the lee board, much depends upon the sail. In Glenn's attachment, I imagine there's a standard size/shape sail for the ACA sailing canoe, hence the fixed locations.
The center of effort of the sail (or sails) should be a bit aft of the center of resistance of the boat. This will cause an untended boat to weathervane and stall facing upwind, the safest position for an untended boat. Think damaged rudder, incapacitated pilot, etc.
Remember, the center of effort will be the farthest aft when close hauled, anything less and the center of effort moves forward.

 

[Bothwell Voyageur]

If you're using a sail with the lee board, much depends upon the sail. In Glenn's attachment, I imagine there's a standard size/shape sail for the ACA sailing canoe, hence the fixed locations.
The center of effort of the sail (or sails) should be a bit aft of the center of resistance of the boat. This will cause an untended boat to weathervane and stall facing upwind, the safest position for an untended boat. Think damaged rudder, incapacitated pilot, etc.
Remember, the center of effort will be the farthest aft when close hauled, anything less and the center of effort moves forward.

Isn't that what I said? Well maybe in a bit more detail

I came to hate the lateen style sail we started with. With so much of the sail out over the water the canoe would roll from side to side when running downwind.

 

[Fitz]

Under the center of effort of the sail is a good place to start. Todd Bradshaw's book is a colorful resource.

 

[Guest]

Thanks to all, that was a good starter lesson. The ACA Sailing Canoe diagram was Leeboard and Sail for Dummies instructional.

But I have Sailing Dummy apples to oranges. A true and dedicated sailing canoe apple, vs the orange of a simple downwind vee sail on a tripping canoe full of gear, with the paddler or paddlers on solo or tandem seats.

With a gear load taking up space midships getting to that lee board 8 inches front of center seems awkward in a tandem. In tandem tripper guise as far as the stern paddler can scramble forward and reach would have to do for leeboard location.

Where that location is from the stern seat on a 20 foot canoe I do not know, but the clamp on lee board will allow experimentation.

just in front of the centre of effort of the sail as far as I can remember.

The center of effort of the sail (or sails) should be a bit aft of the center of resistance of the boat.
Remember, the center of effort will be the farthest aft when close hauled, anything less and the center of effort moves forward.

I dang near understood that. With a downwind sail the canoe will never be close hauled, or even sailed on a close reach. There is a Suzuki motor to make distance in that headwind crap.

The effort of sail may be different with a simple downwind vee sail, especially depending on where it need be located.

The large Pacific Action sail can be mounted about one third of the way back from the bow on the 20 foot canoe, which from what I have read and experienced is the desirable location for vee sails. That position is well aft of the bow seat, and because the PA sail deploys forward with bungee tension, and collapses towards the stern, that should work.

With a Spirit Sail in a 15 or 16 foot solo the reach forward from the center seat to manipulate the sail mount puts the sail right about where it should be front of center hull.

But a Spirit Sail, if it works in the 20 footer, Inshalllah, would be bowman manipulated, and so located in front of the bow seat. The large size Spirit Sail, that far forward, might be more, uh, interesting a responsibility than I would like a bow sailsman.

The Pacific Action Sail, mounted several feet back of the bow paddler, would a better fit on the tandem motorized Miramichi. Then the stern has responsibility for everything, motor, releasing and retracting the sail, sheets and cleats, lee board. Sounds mighty relaxing up there in the bow.

I might have to bring a smaller mid-sized Sprit Sail and provide the occasional jib just to keep myself amused.

 

[Glenn MacGrady]

the orange of a simple downwind vee sail

I know virtually nothing fruitful about sailing, but if you're only sailing downwind, do you really need a leeboard?

 

[Boatman53]

If I am understanding correctly about the sail (it being a triangle on centerline) you shouldn't need any lee boards. Even with the lateen sail on mine downwind with the sail all on one side I would raise both boards. Maybe that is just me.
When I raced Beetle Cats we would raise the centerboard also on the down wind leg.
Jim

 

[Guest]

I know virtually nothing fruitful about sailing, but if you're only sailing downwind, do you really need a leeboard?

Running straight downwind with a vee sail held perpendicular to the keelline would not need a lee board. But both the Spirit Sail and Pacific Action sail can be adjusted on angle, the SS at 30 or 60 degrees, the PA anywhere in 180 degree offset.

The closer to a beam reach the less effective the vee sails become. On a broad reach the hull is being pushed sideways to some degree, even on our ruddered hulls.

Whether or how much a lee board will help tracking in that regard I do not know. The 20 footer has no keel, skeg, rudder or tiller and will be dependent on the stern using a paddle blade.

https://www.google.com/imgres?imgur...ved=0ahUKEwjgwd-t-PXYAhUP2FMKHSMsCwAQ9QEILTAA

It is possible that the lee board may be skeg like useful when using the motor into the wind. Time will tell. This is new ground for me, and the clamp on lee board should be helpful in experimenting without making permanent alterations to the canoe.