Prismatic coefficient study Leaving the length, beam and draft (middle cross section) the same while allowing displacement to go up
with prismatic coefficient (Cp); in this case, going from Cp=.62 to Cp=.70 gains 61 lbs. displacement (12.5%) at the waterline shown. |
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Based on this earlier sketch of a beach proa hull, August, 1999.
The sides of this hull are flat panels, the bottom a "surface of revolution". |
MultiSurf Hydrostatics Model file: prismatic_60 15-Jan-2002 16:51:39 W.L. Length 19.00 ft W.L. Beam 1.00 ft W.L. Fwd. X -9.50 ft Draft 0.75 ft W.L. Aft X 9.50 ft Displacement Volume 7.608 ft^3 Ctr.Buoy. X 0.00 ft Displ't. 487.1 lb Ctr.Buoy. Y 0.00 ft LCB (% w.l.) 50.0 Ctr.Buoy. Z -0.30 ft Waterplane W.P. Area 13.36 ft^2 Ctr.Flotn. X 0.00 ft LCF (% w.l.) 50.0 Wetted Surface Wetd.Area 30.48 ft^2 Ctr. W.S. X -0.00 ft Ctr. W.S. Z -0.39 ft Initial Stability Trans. GM -0.19 ft Trans.RMPD -1.66 ft-lb Longl. GM 33.97 ft Longl.RMPD 288.78 ft-lb Coefficients Waterplane 0.704 Prismatic 0.626 Block 0.536 Midsection 0.856 Disp/length 31.7
MultiSurf Hydrostatics Model file: prismatic_70 15-Jan-2002 16:43:34 W.L. Length 19.00 ft W.L. Beam 1.00 ft W.L. Fwd. X -9.50 ft Draft 0.75 ft W.L. Aft X 9.50 ft Displacement Volume 8.555 ft^3 Ctr.Buoy. X 0.00 ft Displ't. 547.7 lb Ctr.Buoy. Y 0.00 ft LCB (% w.l.) 50.0 Ctr.Buoy. Z -0.30 ft Waterplane W.P. Area 14.65 ft^2 Ctr.Flotn. X 0.00 ft LCF (% w.l.) 50.0 Wetted Surface Wetd.Area 32.52 ft^2 Ctr. W.S. X -0.00 ft Ctr. W.S. Z -0.41 ft Initial Stability Trans. GM -0.20 ft Trans.RMPD -1.9 ft-lb Longl. GM 36.94 ft Longl.RMPD 353.1 ft-lb Coefficients Waterplane 0.773 Prismatic 0.703 Block 0.602 Midsection 0.857 Disp/length 35.6
NOTE: For a definition of these terms, see: Ted Brewer Presents A Primer on Yacht Design
Also:16' beach proa animation, V2 (ama L/B=18): above and below 16' beach proa animation, V1 (ama L/B=16): above and below Ideal Boat Hull Calculator
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