Friday, January 23, 2015

Stem Invention

Its amazing what a difference a deadline makes. Ive been puzzling over a build problem for several weeks now, without success. None of my boat building books has a solution. Even Clem Kuhligs "Building the Skiff Cabin Boy" just skips over the problem.

Heres the problem: The backbone of the skiff consists of the stem in the front, the keelson along the bottom, and the transom in the back. The stem has to go from about where my hand is in the picture below, down to the leading edge of the ladder frame. What makes this complicated is that the angle and position of the stem is very important, and I knew Id have to fool around with it a bit to get it right.

So how could I hold the stem in place in a way that was easily adjustable, but also very strong?


The stem needs to go from where my hand is, down to the frame.
photo jalmberg

As of yesterday, I had no idea how to do this. But once I gave myself a deadline, it suddenly came to me this morning. What I needed was something like a clothespin clamp.

I built a custom clamp out of scrap wood so it would closely fit the stem, shown in the photo below.


Building a custom clothespin clamp
photo jalmberg

Here it is assembled.

 
Assembled clothespin clamp
photo jalmberg

Then I screwed it to the leading edge of the ladder frame, right on the center line. This is important, because of course the stem needs to line up with the center line.


Clamp screwed strongly into frame
photo jalmberg

Then I inserted the top of the stem into the clothespin jaws, and tightened up the whole system with a C clamp.

Amazingly, I can now adjust the position and angle of the stem as much as I need to, and when I tighten the clamp, it is held firmly in place. Im sure this micro-invention has been discovered by many builders, but I was pretty proud of myself, nevertheless.


Strong, adjustable stem clamp
photo jalmberg

Once I finished the stem clamp, I cut the notch in the bottom of the stem that will accept both the keelson and the bottom plank. Then I reinstalled the stem and adjusted it until everything fit right.

The keelson will be bolted to the stem using a long, countersunk bolt through the keelson and stem.

 
Notched stem in place
photo jalmberg

And that was Day 19. Tomorrow, I must tackle the transom. I still have no idea how to clamp that in place, so if you have any ideas, please comment below or email them to john (at) unlikelyboatbuilder (dot) com.

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