41ft tacking outrigger sketch

Please find sketches of a low cost, simple 41ft outrigger canoe. The idea is to create a seaworthy, simple, spartan vessel that could comfortably undertake blue water cruises, yet still retain some very useful features such as shoal draught, and low capital and ongoing costs. I would think that a vessel like this would be best be built using epoxy double diagonal using thin timbers not veneers. Such a method would be very labour intensive, the idea is to built in a poorer country utilising the low labour cost. The total cost of the vessel would be quite modest. It should be noted that in many ways the hull shape is inspired by Wharram Taoma Mana ethnic series double canoe, but extended by three and a half feet to create a bigger hull than can support a small cabin . The twin junk sail is cheap to make and is robust.
Overall Concept
The concept is to provide a large hull for the accommodation and facilities within. This gives the vessel large intrinsic reserves in terms of seakeeping potential and load carrying capacity. The idea is to underload the hull as opposed to overload the hull. Costs are lowered by using wood as opposed to expensive stainless steel and carbon fiber fittings.
Main hull construction details
The main hull is envisioned to be 14mm thick with no outer fiberglass layer. Idea is three layers of thin, narrow sawn timberstrips. The first is 8mm lenghtwise , next is 3mm at fortyfive degrees and a final of 3mm again at fortyfive degrees to the initial but at 90 degrees to the second. Each layer epoxy coated inside and out and also edge glued. This is built on a solid 120mm deep keel which adds a little weight but adds strength. Weight of this keel is 110kg assuming using a heavy wood with a S.G of 1.1. Obviously most boats would not accecpt this additional weight, but it may be acceptable if the hull has excellent reserves of buoyancy and a robust hull that can accept grouding is desired. Note that the solid keel is the method used for all Filipino Bancas, a very numerous and successful craft
Ability to be beached
Without a fixed in place rudder, combined with low draft and multiple crossbeams allowing for multiple purchase points allows for the canoe to be beached using rollers/logs and man power, a very useful feature allowing to get away from expensive commercial boat lifts and allow the hull to be careened after beaching on a high tide
The wide, long side deck, good for exercise
Staying on a boat for a long time it is possible to go a little mad if you do not have the ability to walk around and stretch your legs. The large flat side deck provides this feature allowing the occupants to get some exercise and thus retain a degree of physical fitness. Exercise and physical fitness is in my opinion not to be over rated
Main hull fineness ratio
The waterline fineness ratio for the main hull is 12.5 to 1. The hull shaps is elleptical in section. A narrower or fatter hull is possible if desired by using a differnt ellipse of even a circular arc
Overhangs, freeboard and clearance
Clearance under the crossbeams is 3ft which is 7 percent of overall length, higher than the recommended 6% minimum. If a more realitic length is used say by forgetting overhangs then the clearance gets even better in percentage terms. The overhangs exist to provide damping to excessive pitching that would otherwise occur due to the fine ends. Freeboard is 3ft, the deck is 3ft 9 inches above the waterline, as it sits on top of the crossbeams which are eight inches deep
Why stayed junk sails?
Low cost, low maintenance, easy reefing, simplicity,, oh and low cost
Look of the vessel
The saying is that if it looks right, it is right. For me this boat looks very good to my eye. It is true this is a subjective thing, however i think it is better that in my view it looks right as opposed to not looking right
Steering is intended to be via quarter rudders and bungee cord for self steering
Sail area
I need to do SA/D calculations, going on if it looks good it is good as of now. Rig is tentative at moment, exact sail dimensions and locations to be determined
Some features of this vessel
  • There are two single berths
  • There is 6ft 2 inches standing headroom
  • Only one large hull needs to be built
  • There are two relatively modest mainsails that are easily handled by the solo sailer
  • Crossbeams each consist of two planks separted by wooden blocks to give more depth and hence more strength than a solid wood crossbeam, for only modest extra complexity
  • Minimal electrics, nav lights, interior lights, cooling fan
  • There is a large flat deck to walk which is good for exercise
  • Center of gravity is low

  • Draught is only two feet fully loaded, which is good for beaching
  • The large overhangs reduce performance to a degree, however these provide excellent protection from a following sea
  • The center of gravity is low which is good for safety
  • Stay angles are low, thus reducing mast compression loads
  • The lack of a skeg and fixed rudder permits beaching on remote beaches (with assistance of course)
  • Please note, this vessel is best thought of as a 30ft multihull with overhangs, as opposed to a 40ft multihull

Methods of reducing vessel capital cost
  • Spartan living conditions
  • Elimination of complex centerboard/daggerboard
  • Eliminating luxuries such as separate head, refrigerator, shower, electric winches
  • Use of blocks instead of winches to handle sails
  • Wooden masts instead of aluminium masts
  • Elimination of internal engine
  • Elimination of bridgedeck and the associated weight, windage and cost
  • Only a small part of one main hull has standing headroom, thus minimising windage

Alternate Stern Configurations