Fish Tail Flat Plate Rudder Build

[Flitch]

After hauling the Skyla Brianne, it became obvious immediately that she needed a new rudder. The old one had more worm holes in it than Gramma's garden. As I deconstructed it, I admired the 60 year old workmanship and decided to make a new one out of steel. 2 years of research later, I chose a flat plate fish tail design and starting with a piece of conveyer out of the scrap bin at work, here is what I made.

Previous 60 year old rudder ingeniously built in overlapping yellow cedar:
http://farm2.static.flickr.com/1312/1254000373_5a63574213_o.jpg

Note how it overlapped on different angles from side to side. Someone with more brains than I did this...

http://farm3.static.flickr.com/2657/4041105511_19dbdaa2cd.jpg


Starting with a piece of conveyor from the scrap bin at work...
http://farm3.static.flickr.com/2578/4041761534_59f93cf9b3.jpg

I began cutting out my new rudder..
http://farm3.static.flickr.com/2669/4041015707_2438948b2d.jpg


Yours truly....
http://farm3.static.flickr.com/2532/4041108967_03d62b5ef6.jpg

And the completed shape as of tonight:

http://farm3.static.flickr.com/2773/4049278182_8ca758f7b9_o.jpg

I still have to tidy up the welds, weld a couple or three gussets on it which will run from the leading edge to where the fish tail starts... and also of course prime it, fair it and paint it...

[rbgarr]

Is the wedge symmetrical in plan view? I thought one of the advantages of a wedge was that the angle could be made to offset the prop thrust.

[Flitch]

I read the 4-part series in Professional Boat Builder (http://pbb.proboat.com/ - Dec 05/Jan 06 onward) and gave some consideration to an assymmetrical design. Given my limited experience with square roots and a lack of knowledge about thrust, horsepower and displacement theory, I decided that in my personal evolution on rudder design, I would start with a symmetrical design as it worked well with the previous rudder.