This is a combination of my 18ft dory and my 14ft outrigger. It was not designed from start to be a mulithull, thus there is much room for improvement. However it handles extremely well and has given me the confidence to explore all of Port Phillip Bay (40km x 50km)

The boat is a combination of an 18ft dory I had, and a 14ft outrigger, which was also on hand. The outrigger was originally designed for a proa that I never got around to building. As the dory was designed for rowing, it is not totally optimised as a hull for a multihull. However it's features that are a downside as a rowboat and a plus as a multihull. As a rowboat the dory is tender and although I am fine with it, newcomers find it disconcerting. The high ends which make for high windage when rowing, work to advantage when working as a multihull

Last week we were using the boat as a monohull powerboat with the 3hp Yamaha in the well. It goes very well on a very modest throttle. We could get 4 to 5 knots on half throttle with three people on board. We only used 5 litres of petrol over four hours of motoring.

Some notes on my outrigger canoe, tacking outrigger boat. The main hull is 18ft long and made with 4mm marine ply sides and 6mm marine ply floor. Over this is epoxy resin. The bottom of the floor is covered with fiberglass. I have used housepaint over the epoxy resin. The smaller hull is 14ft long and is heavily built. The large hull weighs about 70kg and the smaller outrigger about 34kg.

On Sunday, 8 March 2009, I took the boat for it's first real trip as a multihull. I motored upwind to Williamstown and sailed back downwind. The boat handled very, very well. There was a bit of spray going upwind into a strong gusty wind a short chop, but not sure what I can do about that.

Coming back downwind was very relaxing. I sat in the aft seat and laid back on the backrest. Surfing on the small waves I was doing about 5 knots, with more sail area I could no doubt go faster. The rudder setup I used with an offcenter tiller and yoke allows me to sit back and have the tiller at my side. It takes a while to get used to it, I kept telling myself push to go right, pull to go left. It has not become a natural action just yet

The boat felt very secure and robust. I was able to move from the larger hull to the smaller hull when required. I felt in no danger of tipping, this I put down to the small sail area, the low center of effort, and the quite high weight of the crossbeams and outrigger. I feel the boat and the concept can definately be extended much further.

Some features of the boat

• I have 2 mast-steps, each on the centerline, 34cm apart. At the moment I am using the aft mast-step.
• I am using a small lugsail at present, but have a much larger conventional stayed bermudan main and fractional jib with a very well made hollow, tapered Oregon mast which is 50 years old.
• The small unstayed lugsail I am using in the short term handles very well. It goes well downwind and reaching. I am yet to test it going upwind.
• My daggerboard is unweighted and probably a bit smaller than the ideal. It has a tendency to pop up when I go sailing, at present I am using a line to keep it down. The daggerboard is shaped to a teardrop cross-section.
• At present I have the option of using the outboard in a well or on a bracket aft. The trouble with the bracket aft is that it affects trim and is subjected to higher loads ifn the boat pitches heavily.
• I am very happy with the shape of the outrigger. It has shown very little drag and has worked exceptionally well so far.
• I have the outrigger well forward, at the same place at the mainhull bow. This is to provide stability when the outrigger is acting as a float and not a counterweight.
• At present I have no desire and see no need to add an outrigger on the opposite side so as to make a trimaran. If I was interested in pure speed this may be an advantage, but for cruising I think it to be a retrograde step.
  
  
• The support for my lugsail is X shaped. This has proven to be very strong structurally. It was made this shape to allow the daggerboard to be rasied and lowered. The downside is that it tends to take up a bit of deckspace
• The two center thwarts (the green painted thwart, and the unpainted thwart behind it) are both removable. The painted thwart can be placed 30cm further aft, this allows for better rowing position when the boat is used with 2 rowers, as the thwart spacing is 1.3m as opposed to 1m.
• I am placing about 60kg of waterballast in collapsable plastic watercontainers near the bow. This is for trim. The downside for this is the time taken to fill them and the fact that they are fragile and not robust,
• The dory (main hull) is framed with 1 inch square hoop pine. This has proved to be very successful. The gunnel is reinforced with 0.5 inch x 1 inch gunnel strip and a similar inwale.
• The outrigger is secured to the crossbeams with 10mm galvanised bolts. The crossbeams are attached to the main hull with 12mm galvanised bolts. Each bolt is secured with 2 nuts so they do not become loose.
• The Yamaha has been faultless. It starts first pull and is very reliable. When taking it out of the well the issue is where to put it. At the moment I just throw it into the middle of the boat, when it is not in use. I place a plate in the well when I am sailing or rowing so as to minimise drag.

Some plans for the future

• Build a smaller new trolley with much smaller diameter wheels, the old wheels have died under the heavy load
• Work out a mechanism using pulleys and block and tackle to assist in getting the boat back onto the wharf. In the past I have been able to do this easily single-handed. But now with the extra weight of the outrigger and crossbeams it is now too heavy, thus I need to use a set of pulleys to get the boat from the water onto the wharf.
• Find ways of shortening the assembly time. It took me an hour last time. This was my first attempt though.
• Build a new bigger lugsail out of dacron and a higher mast. I think the sail is just a fraction small. The changes I made to give the lugsail more curve and body worked very, very well. Because the sail was so close to the gunnel it was difficult to see under it so as to see other vessels. Thus I would like to raise the bottom spar by 6 inches to increase visibilty. I have already bought a 9m x 3ft roll of four ounce dacron fabric and 500m of waxed sail-twine for a future sail. I am happy with my mast, but my next mast I think is best made 2ft higher to allow for more sail area
• Remove center thwart (green thwart) as I do not use this when sailing single handed.
• Investigate making the area from the front thwart to the bow bulkhead a water ballast compartment. This will mean that those sitting in the front seat will not be able to face forward and must face aft.
• Reinforcing the hull bottom longitudinally. So far all has been well, however if I get into a large swell I think some increased structural strength would be prudent. My intention is to double the depth of the keel from half an inch to 1 inch. I would also like to add 2 lengthwise strips, each about 8 inches from the centreline so as to protect the chine from scrapes and to add longitudinal strength
• Working out a place for the motor. Ideally I would like to just rotate it when it is not in use, does this mean a third crossbeam but lightly built?
• Can I use the front mast step with an inclined mast and a gaff rig so as to free up space in the middle of the boat? I could put an attachment on the forward crossbeam to support the mast whilst in this configuration