Lines for 25ft proa

The above sketches are an update of a proa design I did in 2005. The original sketch was not perfect and it can be seen below.

The concept is to make a highly seaworthy small multihull design that combines simplicity, beachability, cost effectiveness plus a small cabin for shelter from the elements. I gave the design a lot of rocker for good motion in high seas plus this allows the hull to be deeper in the water at the center meaning the changes in CLR will be minimised as the proa pitches.

The changes I have made between 2005 and 2008 are;

  • I now show conventional slab reefing.
  • Greatly increased size of the leepod so that is sufficient righting in case of being overpowered
  • The open cockpit is increased in size
  • Roller furling jibs are no longer used and instead larger rudderboards are utilised.
  • The cabin is now lowered and has a roof hinged at leeward. This increases cabin space and lowers windage when not in use
  • The rudderboards are moved outwards by 18 inches to give better CLR - C of E balance.
  • Each mast is supported by 2 stays and a spar to windward. Although the spar has slighly more windage it does support the mast in case of being backwinded
  • The pins that connect the outrigger with the mainhull are further apart so as to reduce loads
  • The sails are now a better shape
  • Another viable alternate rig would be twin unstayed lugsails, this would permit smaller rudderboards than shown

My opinion from 2 years after doing these sketches is that this would make a nice boat. However there would be a lot of work involved. Thus I am tempted to make a smaller, lighter boat, a tacking craft which would not be as fast but would be easier to make though with less performance. I am happy with this concept for a proa but feel that I have tried to do too much on 25', perhaps this layout would be better suited to a 30' proa or larger.