Molds and Transom

With the lofting done, I now have full size templates of the molds, stem and transom.  Now those templates can be transferred to the stock.  Many boatbuilders do that using the “bed of nails” technique.  The heads of sheetrock nails are pressed into the lines of the patterns on the lofting.  Pattern stock is then placed onto the lofting board and pressed in place.  The other half of the nail will then dent the pattern stock, giving you the shape of the piece in question.  The technique is described in better detail in “Building Small Boats” by Greg Rossel.

Most of my pattern stock is plywood, so I went a different route.  From the local art supply store, I bought several sheets of mylar and a fine-tipped Sharpie pen.  The lofting was traced onto the mylar sheets, along with pertinent references such as centerline and baseline.  Using an awl to punch holes through the mylar, the templates were then transferred to the pattern stock.  In the case of the molds and the transom, a baseline and centerline was drawn on the stock, half the pattern was drawn, then the mylar flipped over and the other side laid out.  The mylar made it easy to see the lines when the sheet was flipped over.

2015-05-03 After lofting was complete, the 1/2" ply for the table surface was re-purposed to provide the stock for cutting out the molds.
2015-05-03 After lofting was complete, the 1/2″ ply for the table surface was re-purposed to provide the stock for cutting out the molds.

For the molds, I took off and saved the 1/4″ painted ply where the lofting was actually done, then re-purposed the 1/2″ ply laying underneath as mold stock.  As you can tell from the photo, the plywood wasn’t exactly “premium grade,” but still fell within the category of “not cheap.” (See Rule 2).  I used a jig saw with a fine-toothed blade to cut the molds, and took my time.

2015-07-26 Cutting out the transom.
2015-07-26 Cutting out the transom.

The transom is made of cherry.  When cutting it out, I had serious doubts about my ability to cut a straight line with the jig saw, so I measured the distance from the blade to the edge of the jig saw and clamped a fence to the transom stock.  If I kept the edge of the jig saw against the fence, the line should be straight.

2015-07-26 Cherry transom has been cut out to rough shape. The upper edge has been left oversize and flat; it will be trimmed to final shape after the hull is planked and turned over.
2015-07-26 Cherry transom has been cut out to rough shape.

The transom has been rough cut.  The “ears” at the top will be cut away after the boat is planked and the upper straight edge will be replaced with a nice graceful curve.  Notice the top of the transom has a little bit of tumblehome; that its, the top curves inward toward the centerline instead of flaring out.  This is one of the little details that make Tammie Norrie such a pretty boat.

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