This is a design for a simple 20ft outrigger canoe, a tacking outrigger. Hull beam is just over 2ft which is sufficient to sleep in if required. I have shown a folding cabin/tent setup that should provide protection from rain/wind/sun when neccessary. Additionally when not required it would fold away reducing windage and allow for a large unobstructed working area. The design is based on a very similar 20ft tacking outrigger design from Cape Falcon Kayak. When I emailed the builder of that skin on frame craft he said that as it was larger than his kayaks he was less inclined to use it, additionally it had a narrow bow which tended to dig in.
In response to his first hand experience I have used a straight section amidships to simplify building and also to increase hull volume forward to stop the bow digging into waves. I have included a narrow transom from which it is easy to mount a rudder, whilst the narrowness would allow low drag whether the boat has good trim or not. Lateral resistance would be provided by lee boards or an externally mounted daggerboard.
Looking back on this design I am very happy with it. It looks very similar to Gary Deirkin's Wapa design. I am pretty sure I was yet to see this when I sketched this design. I emailed the above sketches to Peter Mirow in 2006 from memory. I have this hullshape saved as a 3D Model in hullform software somewhere on my computer. If I was to change something now I might be tempted to increase mainhull beam by a couple of inches to allow for more carrying capacity and for a little more comfort
Below is an alternate hullshape for a similar craft. Some dimensions are a length overall of 20ft, a midsection freeboard of 35cm at 300kg and a draught of 27cm at 300kg. Draught is 20cm at 150kg. Maximum beam is 86cm. The shape was made in hullform software.
This hullshape may have some advantages over the hullshape above. The flare of the hull would allow it to be loaded with more people and gear if desired. Becasue of the sloping sides I feel a leeboard would not really work, the only options being a centerline daggerboard or centerboard. This would make options for a berth aboard more difficult. One offbeat possibility is a sleeping/sitting area centrally and two small daggerboards, one forward and one aft. More logically have a single daggerboard forward and a sleeping/sitting area aft of that.
The below hullshape is based on the Tremolino trimaran. It has a much greater inbuilt lateral resistance than the above shape. This should reduce reliance of the board to some degree. The deeper hull should give better motion is a seaway and better tracking. The 20cm draught at 150kg (when crew has stepped out) allows the boat to be brought up a beach, as 20cm is just above ankle height. I have a hullform file for the below drawing, though have misplaced the file for the above drawing, though I may be able to find it somewhere.