PocketShip.net

This question is a little complicated, so I hope I can write it such that it makes sense. The taper at the bottom of the rudder is fairly straightforward: The bottom, horizontal blocking is 3/4" thick at the forward end and tapers to 1/4" at the aft end.

I am having some difficulty understanding the aft, vertical blocking and its relationship to the specially-cut blocking just below the tiller slot. I'm certain the blocking must be taken back to 3/4" thick at the bottom of the tiller slot, but how do I get it that way? I think the most elegant solution would be for there to be a compound taper on the aft blocking so that it gradually becomes 3/4" thick at the top and also tapers slightly from front to back where it is less than 3/4" thick. This would be fairly difficult to accomplish, but I think the best way would be to taper the blocking lengthwise first, then add the width-wise taper as it approaches the bottom. However, if I do this linearly, I will lose the "airfoil" shape before reaching the waterline. So the vertical taper would have to begin at a higher point. I think this is beyond my woodworking skills.

A careful study of the manual, especially the middle picture on page 227, leads me to believe that the aft vertical blocking is the same thickness top to bottom, tapering slightly from fore to aft. It looks as though all the curvature from 1/4" to 3/4" is accomplished on the upper, wider blocking just below the tiller slot. Also, looking at the middle picture on page 225, I see what appear to be pencil lines showing the taper on the bottom edge of the blocking, and an arc showing how the taper will end. It seems to me that this would involve some fairly sharp bending of the plywood, but it sure looks like that is the way it is supposed to be done.

I'm surprised I could find no mention of this in the forum. Maybe no one else had any problem understanding it. Someone please enlighten me!

This part was confusing. What it basically amounts to is a compound taper at the 'triangle' that starts at 3/4" and tapers to 1/4" along the curve and along the bottom. The long, straight aft blocking STARTS at 3/8" not 3/4" and also finishes at 1/4". It starts at 3/8" because that's how thick it is when it meets up with both the 'triangle' on top and the bottom blocking. In other words, if you're tapering correctly, they should all line up at 3/8" thick where the aft blocking meets the triangle and the bottom blocking.

Of course, I wrote about it here

http://sunmonkeypocketship.blogspot.com ... -jump.html

The verbiage from that is:

The trailing edge of the 'triangle' finishes to 1/4" where it's straight. It tapers down from the full 3/4" at the top of the curve. It also tapers from 3/4" from where it's against the 5" blocking. And then, it meets up with the long trailing edge blocking which starts at 3/8" and finishes at 1/4".

If you use a random orbital sander to do the work you'll have a much easier time. Don't try to cut it with a bandsaw or whatever. It's just pine so it'll go fast.

Thanks for the help. Looks like I had it figured correctly (for once). I was aware that the aft vertical blocking is only 3/8" thick at its thickest, just failed to make that clear. I decided to cut the triangular piece out of a 1x10 (1x8s are only 7 1/4" wide these days--I can remeber when they were 7 3/4" back in the 60's). Lowe's has clear 4' 1x10s for about $11, so it wasn't too bad, and I have over 3' left over.

Anyway, I think making the triangular part one piece should make it a lot easier to shape the compound taper. I was going to use a grinder, but I think you are correct about using the random-orbital--less chance of taking off too much wood that can't be put back on.

That's great -- note that in my build, I used a few pieces to jigsaw everything together. I remember it was late and I wasn't about trek out to get a large enough piece of timber.

I copied Truenorth's blog, so do what he says


You're right about the sharp bend for the plywood, though. The plywood cheeks didn't sit perfectly flush at the end of the taper. I wonder if I would have found it easier to laminate the cheek blocks in position so the plywood could bend easier? Either way, didn't really matter. Epoxy filled the small space and it looks beautiful. I just put on a final coat of epoxy last weekend and will varnish this week.