Racing Harrigami, 'Hurry Up' Article by Rob Denney
The Racing Harrigami 'Hurry Up' is a variation on Harrigami, the very successful fast cruising proa. The race boat uses the same leeward hull, and beams, but has a bigger rig and a smaller windward hull.
The racing alterations came about for a number of reasons.
First, obviously, was my desire to win races. While Hg (cruising) is a fast boat, I figured it would be faster still with increased sail area and a lower windage windward hull. The EasyRig on Hg (cruising) was not as stiff as it could have been, despite being very strong. This was a function of the way I built it, not the rig itself. Hg's sail area of 31 sq m could have been augmented by downwind extras, but I was intrigued by the potential of a single sail (Una) rig.
Second, all the interesting races take place on the East Coast of Australia, and I live 2,000 miles away on the West Coast. If I was to trail the boat across, the lower the windage and weight, the easier it would be. With it's full headroom and bunk space, Hg (cruising) is a pretty big trailer load.
Third, the racing rules in Aus require a minimum crew of four. Given that racing is seen as a good way to develop techniques and gear for cruising, and that 95% of cruising is done shorthanded, this is a crazy rule. However, it is still a rule, so racing Hg would have hands to spare. This gives us the opportunity to try a rig which is potentially more efficient than the EasyRig, but more difficult to control.
Fourth, I liked the idea of trying something new.
The new windward hulll is a scaled down version of the leeward hull. 6m/20' long, 800mm/2'8" wide and 1.2m/4' high with a bunk in each end and a small space between them for cooking and navigating. The bunks are sailcloth with pvc pipe frames, glassed to the hull sides. These are light and can be used either way up. Construction is strip planked kiri, with lightweight glass each side and polystyrene foam/glass ends. Took a couple of weeks to build. It is about 80 kgs lighter than the old hull, a significant saving in all up weight, but a direct loss of righting moment, which is compensated for by the 18% increase in beam.
I have built new beams because the old ones are only 5.5m long, and the new boat is 6.5m wide. The original narrow beam meant the beams could be folding and still get under bridges on the trailer. The new beams are demountable and fit into tapered sockets on each hull. This makes assembly of the boat a little slower, but much easier as all the individual components are lighter. two peoploe should be able to assemble.disassemble the boat ob the beach, and with the help of a third, load all the bits onto the trailer. The new beams also provide an opportunity to experiment with a new lightweight, low cost building technique. They will be usable with the cruising windward . Swapping hulls will take less than an hour, most of which will be untieing and retieing the trampoline. When I install the beam sockets in the leeward hull, I will also take the opportunity to sharpen up the bows in an attempt to reduce the spray thrown up. I may also alter the profile to vertical, to see if it reduces the rooster tail at speed.
'Hurry Up' showing full sail, one reef, and deep reef using the telescopic mast.
The rig is a novel approach to the problems of getting lots of sail up high in the light, without the big drag and weight aloft problems when reefed. The mast telescopes from 14.3m down to 7.5. There are a lot of tricky little problems associated with telescoping masts (shrouds, halyards, sail tracks, reefing, battens, section changes in the mast to name a few), which I look forward to solving.
The shrouds were the easiest. The mast is unstayed. Because racing Hg has a reolatively low righting moment along with it's very low weight, the mast is quite light, about 40 kgs. I am currently building this, using a novel, very low cost technique. The materials cost is about the same per kg as for an alloy extrusion, but the carbon mast is far stiffer, and has the material placed exactly where it is required.
The sail track was also fairly easy, at least in theory. We have done away with it, and the sail will have a sock which goes around the mast. This eliminates the drag from the mast, by incorporating it into the aerofoil shape of the sail. This has been done before (windsurfer, moths, Wharram's and Freedoms all use it), but for a reefable sail, there are some major obstacles to overcome.
The solutions to the other problems have been worked out on paper, but not yet tried. I will post updates on them as we progress.
Because the rig is a single sail, the centre of effort is going to be further aft than on the EasyRig. In theory, this will make it very difficult to sail, particulalry getting going after a shunt. Based on my experience with Hg, which sails and shunts effortlessly under main alone, it won't be a significant problem. However, if it is, then another job for the surplus crew will be to lift the forward rudder after a shunt, which will move the centre of lateral resistance aft. What will be unavoidable will be the added sheet loads. Where Hg has a single part mainsheet, which can be held by hand, the racing version will need a small winch to handle the horizontal sheet loads. The vertical loads, usually taken by the boom vang or traveller will be taken by the sail, the same as on a windsurfer. This means the boom has to be mounted 1.5m above the sail tack, leading to increased drag from the section of boom to leeward, and a lot of problems reefing. More on these as they are solved.
If time allows, I will also be fitting assymetric drum rudders and using a pair of whipstaffs (imagine a wheel with a single spoke) for steering.
Harrigami racing should be in the water in July or August. It's first major race will be the Australian Multihull Offshore Championships in Sydney in October. The safety gear and transport for this little exercise is going to cost more than the boat itself. Consequently, I am looking for sponsors, and offering 1 of the 4 crew spaces for sale, to the highest bidder.
Footnote: Since the article on Harrigami appeared in Multihull World and Australian Amateur Boatbuilder, we have had a few requests for a camping proa. That is a small, fast, safe, low cost, easily handled and traillered proa with sleeping space on deck and a windward hull big enough for storing the tent and the cooker.
The new windward hull combined with a smaller rig, lower beam and shorter (maybe 8m/27'6") lee hull, fits this desciption perfectly. This could be loaded on and off a trailer singlehanded, and assembled on the beach or foreshore.
