I've been dreaming of sailing a "big" Pacific proa for 38 years (more than half my life). Lately I've been worried that my design work will die with me, so have decided to publish it. Maybe someone else has the knowledge, means and will to finish it.
A 21 meter proa (69 feet) isn't as big as one might think. It has little accommodation space compared to a catamaran of the same length. On the other hand, the long waterline and low weight have great potential for high performance.
These are the Grasshopper files that do most of the work (Rhino 7 or 8 required). They have been named as "STEP00 (dimensions), STEP01 (Proa_hull), STEP02 (ama), STEP03 (beams), etc." beause they are intended to be used in that sequence. They pass data to each other using the standard Rhino Grassopper components 'DATA Output/DATA Input'. Geometry and other values sit in '.ghdata' files and can be accessed in any order, once they are created in sequence. It can be confusing...
STEP00_dimensions_2026Oct9a.gh STEP01_Proa_hull_2026Oct9a.gh STEP02_ama_2026Oct9a.gh STEP03_beams_2026Oct9a.gh STEP04_shell_bottom_2026Oct7a.gh STEP05_pod_shell_2026Oct7a.gh STEP06_pilothouse_2026Oct9a.gh STEP07_cuts_2026Oct9a.gh STEP08_floors_bulkheads_2026Oct7b.gh STEP09_sails_2026Oct9a.gh
Two pieces were originally written using "Hops" but replaced in this release with standard clusters. That code is duplicated in leePorts_bevels_2026Oct7a.gh and the two "STEP_" files where it is used ('STEP05_pod_shell' and 'STEP07_cuts').
.ghdata files are created and updated automatically in a '\ghdata_files\' folder. They are the way geometry is passed between the "steps". This explains why it is expected that all the steps be run sequentially.
In late September (2026), I wandered into STEP04_shell_bottom and STEP05_pod_shell and started puttering... I quickly got lost in complexity and barely recovered; all of the geometry was intact. I learned how this old code works and to make changes more safely, but avoided major changes. For now.