Design quirks

A bit more about the design and planned building method:

The Carlson hull design software builds up a hull over four polygonal (straight-sided) transverse bulkheads, including the transom.  It gives the dimensions and coordinates of these plus other frames specified by the user.  I divided the 176 inches into 8 sections of 22 inches each, so I have coordinates for 8 frames.  The program also calculates the flat profiles of the strakes that wrap around the frames, and allows you to place the pieces on 4x8 sheets, giving visual printouts and coordinates.

Here's the standard three-view as created by the software.  As you can see it has the basic outlines, without seating, decking, floor, thwart, skeg or anything else.  The rest needed some work.

There were many more things to figure out, such as the shapes and sizes of the bench risers, seats and skeg, the depth of the floor, the angles and overlaps between strakes, etc.  I worked all that out by plugging  coordinates into Excel and working out formulas.  High school trigonometry helped a lot!  I also converted everything to millimeters just in case--Excel does not like fractions and 5.81 inches is hard to measure.

Because the program assumes carvel-built design (with the strakes flush against each other), I have to add enough extra width to the strakes so they can be beveled and glued together.  I will have to bevel the plywood (after scarfing pieces together--more on that later) using hand planes I bought cheap at an antique store.  I plan to use epoxy and bronze ring-shank nails that will be set (recessed) and clenched on the inside, then the indentations filled before painting.

I also had to figure out some basics about the centerboard and the sails, to make sure everything fit around the frames, decks, etc., and that the centerboard and sail placement was correct for a balanced helm, not only for the chosen rig but for the three alternatives. It all took a fair amount of pencil-and-ruler-on-paper work.  I will post a more detailed drawing of the design with the extra features, but it will take some time because my pencil sketches need detailing and prettying up.

Next time, a few more design details.

boatbuilder