Quarter Knees

The quarters of the boat are the two corners located aft, or at the back of the boat.  Quarter knees are triangular shaped pieces that help tie the boat together.  As the breasthook ties the sheerstrakes to the stem, the quarter knees tie the sheerstrakes to the transom.  Like the breasthook, the quarter knee has a tab at the end for attaching the inwale, all the angles are bevels, and it has to be curvy so that it looks good.

2017 07 08 Quarter knee pattern.

I like to start out with a pattern made from scrap plywood.  I suppose it isn’t absolutely necessary in this case but it helps to be able to see what I’m aiming for.

2017 07 08 Setting the camber.

As if there aren’t enough bevels to worry about, the quarter knees have a little bit of camber.  Rather than extend across the transom on a horizontal plane, the quarter knees are tilted up a little bit.  The transom is already stained and has two coats of varnish on it, so I used a piece of masking tape to make my lines.  The lower line in the photo above is level; the upper line represents the camber.

2017 07 08 Determining the bevel on the transom.

In this photo I’ve already cut the bevel where the blank fits against the sheerstrake, now I’m determining the bevel against the transom.  The transom has a little bit of tumblehome.  Instead of the sheer flaring outward as it did near the stem, the sheer cants inward a little at the transom.  What that means is that when cutting the bevel where the knee fits against the sheerstrake, I trimmed the top edge of the blank – not the bottom edge as I did for the breasthook.

2017 07 08 The bevel on the sheerstrake is pretty good; but the bevel on the transom needs more work.

The bevel at the transom is a compound bevel.  If you’re gutsy, you can lay it out and cut it in one fell swoop with your favorite power tool.  I took a cautious approach, and snuck up on the bevel with hand tools.

2017 07 08 Quarter knee held in place with temporary screws.

When I cut out the final shape on the breasthook, I laid out the pattern and cut from the bottom of the blank.  This was because the sheerstrake had some flare near the stem.  The situation is reversed at the transom due to the tumblehome.    So I cut the shape from the top of the blank, not the bottom.  That way I can trim the tab to be parallel to the sheer, and I won’t cut the tab too narrow.

Like the breasthook, the quarter knees are held in place temporarily for now.  I won’t glue them in place until after the inwales are cut and fit.  I’m sure there will be some final trimming and fitting during that process, especially near the tabs where the inwale joins the knee.  That trimming will be a lot easier if I can take the knee out and mount it on the bench or in the vise.

One thought on “Quarter Knees”

  1. after building a Glen L 19, a Meadowbird and a Sherpa, I found too the pleasure of building a plain ole BOX,,, square box…. and if you make precise cuts, the box can also be somewhat challenging.,,lol.. on a boat NOTHING is “plum/square”, meaning plum OR square. Geech !


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