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  #1  
Old 05-22-2010, 02:19 PM
Tima Tima is offline
 
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Location: Hampton, NH
converting a troller dory to sail

My name is Tim Brown, and last year I built a 16' troller dory from plans designed by Paul Butler in Washington State. I built in a motor well just aft of the center thwart which I would like to use for some type of centerboard. I already have a leg a mutton sail rig for a Payson Nymph which I would also like to use. My question is since it is a double-ender, should I try to attach a rudder to the stern, or try to steer with an oar setup? Also, rather fool around with a centerboard, your thoughts on just adding a deeper keel. The one I have now is about 12"x 3.5" deep. The boat seems to be designed to sail, but I am a novice as far as figuring out questions like these. Any assistance you could give me would be greatly appreciated. Thanks, Tim
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Old 05-23-2010, 08:05 AM
ancient kayaker ancient kayaker is offline
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Tim: let me first welcome you to the forum! Also I invite you to post pictures of your boat.

A rudder can be attached to the stern: the steering oar may not be very satisfactory. Rudder forces can be quite high so make it solid. Technically pintles are supposed to be used but I used ordinary house door hinges with removable pins successfully on my first sailing effort.

A double-ender can be rather slow to turn even with lots of rocker, in my experience, especially with a long keel. It should sail with that keel, in which case you don't need the centerboard, and the location of a motor well is likely to be too far aft to suit a centerboard anyway.

The hardest part is going to be finding the best mast location for balance. I would start with the mast located 1/3 the length of the sprit boom forward of midships. You want the boat to sail with a slight tendency to turn into the wind which you will correct with "lee helm" -tiller leewards to prevent the stern.

For my first sailing effort (a 14' canoe) I made the sail mount position adjustable and started with it midships: it worked better a foot or so forwards of that position but did not seem to matter much. However, that boat did not have a keel so I used a leeboard; with its long keel you boat will likely be more sensitive to mast location.

A sail intended for the tiny Nymph is not going to give a 16' boat a sparkling performance so it's not worth your while going to a lot of trouble unless this is the first step toward something more ambitious. Later you may wish to try a larger mainsail and use the Nymph sail as a mizzen.

Sail safely!
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Old 05-23-2010, 12:46 PM
Tima Tima is offline
 
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More information, possibly too much

[/right]
I appreciate how fast you got back to me. The 60 sq. ft. sprit sail is used on the Surf and the Gypsy which both are about 16' long with about the same beam and rocker. I am not an experienced sailor as many of the folks here are, so an undersized rig is most likely ok. The rudder setup sounds great, as I really didn't want the oar method of steering the boat. The boat is very light, maybe 120lbs. and I was just wondering if I could slide a centerboard insert through the motorwell to assist with tracking. The center of the well is about 10' from the bow of the boat, making it not really that far aft. I guess to position the sail you need to have the center of it directly above the center/leeboard. I could most likely do this if I make the mast partner removeable for motoring or just rowing. Since the motor well is 4-5' from the stern, I just don't know if the keel is long enough, and also what dimension should I make it. The only other question is how far below the bottom of the boat should the centerboard go. I just don't feel like building another boat at this time, and would like to use what rudders, mast, spars and sails, and possibly the leeboard that I have from Ruben's Nymph. I do thank you for your help to a thorough novice boatbuilder. Tim Brown
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Old 05-23-2010, 01:11 PM
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Ike Ike is offline
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Back in my youth (dreams of bygone days) my dad and I did much the same as you are doing with a small utility type boat. Only we used leeboards rather than a center board. And it ended up sailing pretty well. I learned to sail in that old boat. We built our first mast to lightly though and it broke so we had to make another one. Live and learno.

You could go with a centerboard. Two feet below the bottom of the boat should do it, by a foot wide, one inch thick. Use a clevis pin or one with a toggle to hold it in place. Put several holes in the board up and down, 2 or 3 inches apart so you can experiment with adjusting the depth of the board. In fact you can do the same with the trunk to move it fore and aft if the trunk is long enough. Just make sure none of the hole in the trunk are below the waterline when the boat heels over.

I would also go with a rudder. Ours was offset from the center line so we could still mount an outboard but it worked just fine.

Dories have been rigged for sailing for centuries so it should work out well.
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Old 05-23-2010, 07:33 PM
Paul B Paul B is offline
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Originally Posted by ancient kayaker View Post
You want the boat to sail with a slight tendency to turn into the wind which you will correct with "lee helm" -tiller leewards
Are you sure about this?
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Old 05-24-2010, 11:36 AM
ancient kayaker ancient kayaker is offline
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Paul: I have always understood a lee helm setup to be preferred. The reason usually given is that, with the opposite weather helm, releasing the tiller would allow the boat to turn off the wind, not perhaps what you would want if you are grabbing for a loose sheet or maybe even have fallen over the side. What did you have in mind?
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Old 05-24-2010, 01:23 PM
Paul B Paul B is offline
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Quote:
Originally Posted by ancient kayaker View Post
What did you have in mind?
I really can't tell what you are trying to say at all.

No one in their right mind would ever set up a boat with lee helm. The primary reason is you want the rudder to work as a lifting surface, working with the keel to provide hydrodynamic lift. The secondary reason is for safety, as a boat with weather helm will round into the wind and stall, rather than fall away from the wind.

In the case where the boat is set up for weather helm you need to pull the tiller to windward, not to leeward, to counter the helm.
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Old 05-24-2010, 03:51 PM
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Doug Lord Doug Lord is offline
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Quote:
Originally Posted by ancient kayaker View Post
Paul: I have always understood a lee helm setup to be preferred. The reason usually given is that, with the opposite weather helm, releasing the tiller would allow the boat to turn off the wind, not perhaps what you would want if you are grabbing for a loose sheet or maybe even have fallen over the side. What did you have in mind?
-------------------------------
Terry, I really HATE to say this but "B" is right. If the boat has weather helm the tiller is held slightly to weather of the centerline. If you let go of the tiller on a boat with weather helm it will turn into the wind.
Lee helm is generally to be avoided like the plague: it can be dangerous and it negatively impacts sailing upwind. A boat with lee helm requires the tiller to be slightly to the lee side of the centerline when sailing upwind and when the tiller is released the boat turns downwind-which can be rather violent in any wind.

You also said this:
Quote:
Originally Posted by ancient kayaker View Post
You want the boat to sail with a slight tendency to turn into the wind which you will correct with "lee helm" -tiller leewards to prevent the stern.
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Old 05-24-2010, 05:42 PM
Paul B Paul B is offline
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-------------------------------
Terry, I really HATE to say this but "B" is right.
I am always right.
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  #10  
Old 05-24-2010, 10:12 PM
ancient kayaker ancient kayaker is offline
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Of course he was right, at least on this occasion. I must have had brain cramp or something! Must get that medication checked!
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