Proa sketches in Rhino

Grasshopper Salon/Coach, July, 2015

Yet another iteration of the design spiral on this 70' Pacific proa. Still, nothing is resolved or "final". Instead of converging toward resolution of issues that were identified two decades ago, this cycle has been about extensive use of Grasshopper to parametrically define every curve and surface.

Turntable Animations

Hull and deck surfaces in Grasshopper were tackled in the Spring of 2014, including asymmetric hull shapes. This time, Grasshopper code bits were written for:

Some of these code files are quite complex, developed and refined over long periods of time, while others are simple, specific to a particular problem and were written very quickly. They provide the ability to precisely fine-tune shapes and change them easily.

Unresolved Issues

Several obstacles have kept me churning through alternatives instead of refining a complete design:

  1. Crossbeam position and size - Simple Wharram-style beams attached at both main hull gunnels are an obstruction to useful space unless they are either very high (explored earlier) or far "forward", requiring a longer support beam for the mast and cockpit area between them.
  2. Companionway access from the cockpit down into the main hull. As the proa gets larger, it makes sense to allocate more of the bridge deck area for internal use (accommodations). This increases the distance that must be crossed before stepping down into the main hull, since ~70' isn't big enough for enclosed full standing headroom (as far as I'm concerned). Possible solutions include two entrances instead of one (intrusive on limited interior space) and/or moving the mast to windward of the cockpit, out of the way of a single, central entrance.
  3. Big salon table (for 8?) with 360 degree view. To windward or to leeward? Maybe room for only six?


For now, some decisions have been made:



Floor Levels from Galley, through "Dressing Room"/Cabin Access to Head (6'3" people)

NOTE: Bridge deck clearance at rest would be 36" - ~six inches higher than shown.


In this long series of proa sketches, many features stay exactly or nearly the same (hulls, crossbeams, interior accommodation, windward pilot station, position of scaled "people", etc.) while experimental changes are made to various other parts (pod/coach shape, mast position, companionway, decks, cockpit, etc.).

Quick hacks to reduce pod volume forward - length dropped from 41' to 30', yet left all accommodations untouched except for reduced storage in the heads at each end:

Or an alternative to chopping them off:

October/December, 2021

Spring, 2018

January, 2018

Spring Equinox, March, 2016

Winter Solstice, December, 2015

Windward Pilothouse, Leeward Salon, Single Entrance... August, 2014

Coach Dimensions... August, 2014

Grasshopper hulls, Apr 16, 2014

interior - below beam... Apr 5, 2014

wide coach roof... Mar 31, 2014

coach/pilot roof shapes... Mar 26, 2014

safety ama musings... Mar 24, 2014

old and new... Mar 16, 2014

Model Notes history...

These sketches of a 70' Pacific proa were done in the process of learning Rhino CAD. Nothing is final. The basic parameters of the vessel were defined decades ago.

more Grasshopper coding