9½' Dinghy
Design Number 230
1984
![]() |
I spent quite a lot of time thinking about how the mold was to be built of steel. I came to be increasingly concerned about the work involved in trying to recreate the sweeping shapes of traditional lapstrake wooden plank layout in steel. I felt it would be much too complex a project.
The result of this cogitation was to try the idea of making the laplines all straight lines on the body plan view. This looked good on the drawings, and the work involved in building the molds should be considerably reduced. The layout is much simpler, and the offsets are just given along the laps, as if they were diagonals.
The wooden lapstrake construction shown on the plans is a good way to build the boat. The simplified lap layout and lofting will make fitting the planks much easier and thus quicker.
If a sailing version is desired, I'd use the rig and parts off the 9' Pacific Peapod design.
| Particulars: | Imperial | Metric | |
|---|---|---|---|
| Length overall | 9'-6" | 2.90 m | |
| Length datum waterline | 8'-3" | 2.51 m | |
| Beam | 4'-6" | 1.37 m | |
| Draft | 0'-7"/2'-6" | 0.18/0.76 m | |
| Freeboard: | Forward | 1'-7" | 0.48 m |
| Least | 1'-0" | 0.30 m | |
| Aft | 1'-2 3/8” | 0.36 m | |
| Estimated structural weight | 90 lbs. | 41 kg. | |
| Displacement, to DWL | 260 lbs. | 118 kg. | |
| Displacement-length ratio | 207 | ||
| Sail area | 58 sq. ft. | 5.39 m2 | |
| Sail area-displacement ratio | 22.78 | ||
| Prismatic coefficient | .586 | ||
| Pounds per inch immersion | 110 | ||
| Entrance half-angle | 29° | ||
Note: The displacement numbers are calculated to the arbitrarily chosen DWL.
The calculated ratios of displacement-length and sail area-displacement will vary widely depending on the loading of the vessel.
The calculated ratios of displacement-length and sail area-displacement will vary widely depending on the loading of the vessel.
