Tolman Skiff

I'm just about done taking the offsets off the boat (Tolman Jumbo) ...a big job. Since my boat is stuck diagonally into a garage-shop that's not quite big enough for it, this has been a bit challenging. Normally, you'd set up to take measurements more perpendicular to the hull ...especially important for the sheer line, but there just isn't room for that kind of setup in my garage. I've had to painstakingly use a plumb bob from a squared-up and level line across the boat and a centerline level line. The boat is jacked up and level to the centerline string and I had to move a set of uprights and an aluminum straight edge from station to station. Since a plumb bob hanging to a felt pen line that follows a sloping sheer can introduce some error, I repeated measurements and measured both sides of the boat which I can average (also makes up for not-quite-level horizontal transverse reference above the boat). The error should average out when I've got it in the software. I'll be utilizing ProSurf and Rhino 3D for fairing the curves. I used stations on 6" centers for the whole bow area (high curvature) and 18" centers for the rest of the boat.

One piece of feedback that I had for Renn is that the building sequence for the bottom panel assembly could use a minor update. His process was developed when he built exclusively with 12' panels (and I believe his latest build used left over 12' wood also.) When he lays the bottom panels into the building jig, he depends on alignment of factory edges along the keel to define a good keel line. There is a mold near Station 6, one aft, and one that's in between that you move around until it fits. Fine for 12' wood. For 12' of wood made by scarfing 8' and 4' pieces however, the factory edge may no longer be perfect unless you had perfect alignment in the scarf. I thought that I did, but halfway between the aft mold and the Station 6 mold, I have a 1/8"+ hollow along the keel. At about 10" to either side though, the bottom panels recover to what they should be and are flat (I have a 10' long aluminum straight edge for checking these things.) I'll cut a couple of ovals of glass to fill this, but it could've been avoided had there been accurate specs for angle and location of the mold that goes between Station 6 and the aft mold. My lines work (above) will give me opportunity to specify this exactly and I'll post the results to the Yahoo tolmanskiff group in the files or photos section. An accurate half-way mold would give you something to temporarily screw the bottom panels into and guarantee that no funny things are going on.

Brian Dixon

See Brian's website: