Aligning the molds and checking the backbone

Holes are drilled in the molds and a string used to make sure they are well centered.

I just had to put a batten on the sheer to see if it looks ok.

Building the strongback

Not too many pictures of building the strongback.  This is a serious building jig for a small boat.

I couldn't resist putting the molds on once it was together.  Its looking ok so far.

Finishing up the backbone

Here I am finding the shape of the tapered keelson, using techniques described in John's book, How to Build Glued-Lapstrake Wooden Boats.  This is probably the best boat building book I have come across so far.  Not only does it have lots of details about building this particular boat, it also has tons of great boat building and woodworking information, tips, jigs, etc.  

Using clamps to make sure the stem and transom knee are held square to the keelson while drilling and screwing together.

Some views of the backbone, dry-fitted for the first time.

Transferring the offset for the rabbet line from plans to the keelson.

Epoxy applied to the backbone, ready to put together.  Thickened epoxy, not shown, is used to glue the pieces after this first thin coat soaks into the wood a little bit.

Stem is finally glued on.  I hope it is in the right place.

Cupped Transom

You can't really tell from the pictures below, but the day after I cutout the transom, I was shocked to find it curled up on my table top the next day....curvature was enough that there was a 3/8" gap between the straight-edge and the middle of the transom, shown below.  It was really more drastic that it appears in these photos.  If I pressed the top of the transom flat to the table, the bottom would be lifted off the table surface about an inch.  

What I didn't know was that after cutting the shape out, the board should have been left standing on end so both sides can absorb moisture evenly....but, I left it laying flat on the table, and the result was the cupping.  Not knowing that yet, I went ahead and dry fit it to my backbone and left it like that overnight.  With both faces exposed to the air, the next morning I found it was nearly back to a flat surface.  Now, a couple of days later, it is just about perfectly flat again.

transom continued

Drawing out the outer and inner faces of the transom on my glued up blank.

To create the bevel between inner and outer face, I make many cuts in the edge, from the line drawn for outer face, to the other edge of the board (inner face).

Once the cuts are in place, I use a chisel to create the bevel.  I don't trust my jig saw to a task like this.  It is a little time consuming, but works.  First I make a groove where the edge of the bevel will be.

Then, I knock off a bit of each bevel quickly.

After that, I clean up the rest of the wood that needs to be removed with the chisel, cutting down to almost make the saw marks dissappear.  The picture below shows the rough cut, but I forgot to take one after removing more wood.

Once the bevel is close, I take a coarse file and gently work it until the cuts are just about invisible.

Then, clean it up with a fine file and finally sandpaper.  It seems to have worked out pretty good.  In some places you can still see a saw cut or two, but since this will have a plank glued onto it, it shouldn't matter.

keelson, transom and stem

Marking out the stations on the keelson with enthusiasm.

Using a router and jig to try to get nicely matching edges to glue up for the transom.

Transom laid out ready to glue...my first attempt at spline joints.

A rather oversized blank for the stem ready for glue....

The keelson, stem, and transom is all African Mahogany.  It is a nice hard wood, but is very hard to work and shape because of the grain characteristics.  I didn't realize that until after buying it for the backbone of this boat.  I used a bandsaw to get out the stem shape and then rough in the bevels.  I can't seem to use any kind of hand tool like a plane or chisel effectively on this wood.  I had to finish the bevel mostly with a hand-held belt-sander and then flatten it as much as possible with the spoke-shave, which works ok but still tears out grain even when set very shallow.  In any case, the stem looks ok at this point.  I can see that beveling the keelson will also be a pain with this wood.

Finishing up the molds

Mold no. 8 checked against the plans.

The process I use is to first check the identical half molds against the full size drawings in the plans.  Then, lay out the entire mold, with one half still directly on the plans.  I line up the top edges with a straight edge, then check the beam at the top of the sheer plank....this should correspond to the offsets that are provided with the plans.

On this mold, my measurement comes out very close to 46", which indicates a half-breadth of 23", or as written in the offsets 1-11-0.  (One foot, 11 inches, zero eights).  I slightly adjust the half of the mold not on the plans until the beam is exactly 46" inches at the sheer, then screw it together.

Here, the straight edge lines up the tops of the mold halves.

Mold 10 going through the same process...

All 5 molds mostly completed.