After laying out the centerboard slot on the keel, first we'll drill a whole at each end of the slot, then using the saw we'll simply cut between the two. Here's Jonas on the first of the holes.
To insure that the hole is at the right angle, we're using a guide block with a hole already drilled through it. The bottom edge of the guide block is cut to the correct angle that we want to bore. To keep the hole nice and straight we're using a "barefoot" auger, an auger with the lead ground off to prevent it from tracking off coarse as it bores through the timber.
And here I am drilling the hole at the other end.
With the holes drilled to define the ends of the centerboard slot, it's on to the fun part. We've clamped a piece of plywood to the side of the keel to line up where the slot is to be cut. The plywood serves as our guide as we make the plunge cut into the keel and it keeps the cut nice and straight.
As I said before the circular saw we're using has an 18" diameter blade, but even with such a large blade it only has a maximum depth of cut of about 6", so we'll have to cut it from both sides to get all the way through. But enough yapping, lets get to cutting.
Aside from the initial torque when you first pull the trigger, this saw is pretty smooth. And since we're cutting Alaskan yellow cedar, the saw plunged right in. The weight of the saw would make it a bit of a bear if you were using it all day long, but for what we were doing it wasn't bad at all.
With the saw plunged all the way into the keel, cutting straight through proved difficult, but we found that by plunging the saw as we went, the cut went easily enough.
A lot of saw dust though.
With one cut complete, it's on to the second. This time donning a dust mask so as to set a good example for all the kiddies out there.
Here's a good look at the whole keel while we wait for me to finish the cut.
Two cuts complete, we flip the keel and start from the other side. If everything lines up the way we planned these cuts will line up perfectly with the two we made from the other side and we'll have our centerboard slot.
Anytime you're wielding a saw like this one you're bound to draw a crowd, so by the last cut we had a few spectators. This final cut proved a little more difficult than the others as the piece we're cutting out was pinching the blade in the kerf. But we persevered.
And with the work of the circular saw complete all that's left to do is finish off the cuts the old fashioned way.
A little chisel work and a little sanding...
And we've got ourselves a centerboard slot. Not bad if I do say so myself.
After standing back to admire our handy work on the centerboard slot, we hauled the keel back up to the loft to begin assembly. We'll assemble all the pieces of the backbone right on the loft floor to ensure that everything lines up just right. We'll start with the stem. After a little final fitting, we drilled the holes for the bolts that will hold the stem to the knee and the knee to the keel, and thus the stem to the keel too. Did you follow that?
Here's the stem all fit and fastened.
Once we had everything dry fit just perfectly, we took it all apart again. After we have it together again the next time, it should never have to come apart again. For final assembly we use bedding compound...
And a twist of cotton under each of the washers.
Now that's a fine looking stem.
Moving aft, we had to remake the lower deadwood piece (the smaller triangle, slightly darker in color) 'cause the original was just little bit too small. Luckily we had a scrap that was about the right side. It's a good fit now.
Before we can bolt together the stern section of the backbone there are a few things we have to do. First, we have to nib in the inner keel. For most of the length of the keel there is a cheek piece attached to each side of the keel to extend the back rabbet, but at the deadwood, there is an inner keel that serves that purpose. The back rabbet is the surface of keel against which the inside face of the plank lies. The back rabbet is extended to provide more surface for fastening the planks to the backbone.
The inner keel is nibbed into the top of the keel rather than having it taper down to a feather edge which can be a bit fragile. After laying out the nib, we cut a series of saw kerfs. This allows the quick removal of the material with a slick.
See how quick that was...
And not a bad looking fit either.
You can see now where the inner keel will lay on top of the deadwood. We decided to add a knee between the inner keel and the stern post for a bit of added strength.
With the nib cut, we put the inner keel piece in the steam box for a few minutes, then bent it into place. It lay into place perfectly.
With the inner keel in place and everything lined up, we could start drilling the holes for the bolts that will hold it all together. First though we made up some temporary floor timber pieces to line up the auger and provide a flat surface for the bolts to land on. Notice that each of the temporary keel pieces is cut at a different angle to match the angle of the inner keel at their specific location.
Now we just need to bolt it all together. Once we have the keel on the building jig, we'll simply remove the temporary floor timbers one at a time and install the real ones which are already fastened to the frames.
And that ends our first week back in the boatshop. Definitely a productive start to the quarter.
In closing I leave you with this parting shot of the keel and stem assembly. This is the first time our little catboat got to sit on her keel.
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