Transom on the Tangent of 3 Degrees

Here you can see the transom hanging on to the jig and the keel coming in at more or less a right angle.




The tangent is equal to the ratio of the opposite side over the adjacent side of a right triangle.

Right now we are at 2 inches divided by 39 inches or about 2.9 degrees which is probably way close enough.

The tangent of 3 degrees equals 0.0524077793.





In the plans the designer specifies that the transom should be raked forward 3 degrees. Now I have a suspicion that when Graham was building the first EC 22 Southern Skimmer that he just tilted the transom in a wee bit and let it go at that. He could not really write that on the plans so he put down 3 degrees. Now I am going to spend an hour or two trying to set the transom within a couple of minutes of 3 degrees.










I know the stem of a boat can be difficult. The stem is often curved, it has rabbits, and bearding lines and plank landings. The stem can be complicated but a transom that is pretty much just a flat board stuck on the back of the boat. Right?


Well not quite!


Checking to see how the matched halves of the transom fit the pattern.


Here I am separating the halves and laying them out on the full size drawings. Hmmm any differences between the plywood and the drawings are due to humidity induced paper distortions.







Checking to make sure that I am keeping the edges of the transom square as I plane them down to the lines.






I clamped two pieces of plywood together and cut out both halves of the transom at the same time. I cut just outside the line using the circular saw set to a very shallow cut. Then I used a sharp plane to bring the pieces just down to the line.










I transferred the curve of the transom from the plans to a 2x8 that will support the transom on the jig and maintain the specified arc.