Rudder, Tiller, Leeboard...
I was doing my home work at Jim Michalak's site regarding rudders and leeboards (more leeboard info) when I ran across his review of Ted Cary's idea about using nylon seat belt webbing in place of pintles and gudgeons. (The hardware that holds the rudder on.) Now I have a set of bronze hardware from Jamestown Distributors, but this method intrigued me. Mounting and removing the rudder should be easier. Though it takes a little time to make, the materials cost is negligible.
Here's Jim's sketch. His write up on it is here.
And here's how I decided to modify it. Ted also glued his webbing with epoxy. I'm going to try using PL Premium (of course) but I'm also interested in some kind of mechanical hold that might let you change the webbing if necessary. Here's one possibility.
This is similar to the way canvas is held in directors chairs. A hole is drilled at the bottom of the Kerf, and the webbing wraps around an 1/8" brass rod. I'll let you know how the experiment turns out.
I started with a 10" piece of 2x6. I cut a 7/8" deep saw kerf down the center. The yellow dotted lines show how I modified the design by tapering the insert. In instrument building this trick is used to join necks to bodies. In theory when you insert it it will snug it up against the transom.
This could all be done with a hand saw, but I used the table saw. I don't own a taper jig. But here's an easy way to cut a taper using a scrap of plywood. I set the saw to 25 degrees and clamped the fence about 5 inches away. I ran a scrap of plywood throught the saw. I then lined the cut edge of the ply up with marks I made on the BOTTOM of the wedge stock. I stapled it in place with 1/2" staples and ran in through the saw. I then pulled it off and stapled it to the other line. Works great.
I laminated two 1/2" pieces to make up my rudder and leeboards 1" thick. I used 1/2" on Featherwind, but it sometimes seems a little flimsy and isn't very straight. It's also hard to imagine standing on the leeboard to turn her over. So I'm beefing these up a little. If you decide to use 1/2" I recommend laminating it from 1/4" to prevent warping. (If you lack enough clamps you can use heavy weights and/or dry wall screws to laminate these.)
I'd like to confess that I'm getting a little carried away with these sailing bits. The boards can be simply 1/2" ply with edges rounded and the mast can be a single 10' 2x4 left full 3.5" wide for the first 3 feet then tapered to 1.5" at the top. Round the edges and call it a day. It's mounted athwartship (1.5" ends pointing to the sides of the hull) so the most stress is carried where it's stiffest. This is what Dave Carnel calls for on his $200 sailboat Nutmeg. (a.k.a. Featherwind) It seems like "underkill" at first glance, but if you think about it, if you're in the kind of weather that will break a 2x4 maybe your sail should be down anyway. I'll actually be making a mast to these dimensions too, and fitting the hull with multiple mast step positions so I can test different rigs, and document them.
The tiller is made from the triangle left over from the skeg. 3/4" x 3.5" stock. I drilled a one inch hole in it, then sawed to the hole to form the slot for the rudder head. Since the rudder stock in 1" thick and has been rounded with a 1/2" radius router bit, it fits the slot perfectly. Very satisfying. Could be left square though.
On Featherwind I made the rudder and leeboard of 1/2" ply with the edge just rounded. It works fine really. Though the leeboard vibrates at certain speeds. I decided (for some crazy reason) to shape my blades this time. Rule of thumb is tapered and rounded leading edge, thickest point about a third behind the leading edge, and a smooth taper to a rounded trailing edge of maybe 1/4". (I did read one report of vibration of a foil being cured by the trailing edge being square instead of round and beveled at about 30 degrees.) I used a hand saw to score the rudder blade to make stock removal easier. I used chisel, belt sander etc. to remove the stock. It was a pain.