The Original Harryproa Concept

"Harry Proas" by Rob Denney, as appeared in Multihull World, Australian Amateur Boatbuilder #38, and American Multihulls

Harry Proas

A proa is a double hulled vessel with all or some of the following attributes:

1. The rig is mounted in or on a hull.
2. The hulls are frequently different lengths and shapes
3. Steering and leeway prevention are also in one hull, generally but not always, the same one as the rig. Steering can be achieved by rudders, paddles, oars, crew movement and fore and aft movement of either or both of the centre of effort, or centre of lateral resistance. Leeway resistance can be provided by hull shape, leeboards, daggerboards or oversize rudders.
4. They are able to sail in either direction. This generally involves shunting (the equivalent of tacking or gybing, see diagram), although as with most things proa, there are numerous variations of this as well.

All these variations indicate that the ultimate proa is yet to be built.

Proas were probably the first improvement made to a floating log by early sailors. A second, smaller log was lashed to a cross beam to stop the main log capsizing. Rigs were added later when technology allowed. These boats have been scattered through the Pacific and Indian Oceans, where they have been undergoing development for hundreds of years. Consequently they are very highly developed for their conditions of use, and the materials they are built from. They sail in generally warm, trade wind conditions with crew who are not only fit and agile, but are superb seamen. They range in size from small models ballasted by baby coconuts up to large ocean crossing vessels capable of carrying a dozen people and their supplies for many weeks at sea.

However, they are by no means the end of the story. Our ancient Polynesian cousins had no access to epoxy, fibreglass and carbon plus they seldom had to sail upwind in less than idyllic conditions crewed by the wife and kids and driven by the need to be back at work by Monday morning. If they had, then their boats would be far different to what they are.

Western sailors have been slow to adopt proas. This is partly because until now they were difficult to manoeuvre, and partly, I suspect, because many people are unhappy with boats which are not symmetric fore an aft They received a brief burst of publicity after the 1968 Singlehanded TransAtlantic Race (OSTAR) when the 12m/40' proa Cheers achieved 3rd place. Cheers was designed by the legendary Dick Newick and was a masterpiece of elegant simplicity. It was sailed by Tom Follett, arguably the best, if not the highest achieving, yachtsman of his time. Cheers was different to traditional proas. It had the rig, rudders and accommodation in the windward hull and looked like a double ended trimaran with the windward float missing. The benefits of this set up are reduced weight, windage and stress of a second set of beams and a third hull and the weight of the rig and foils are all in the best place to enhance righting moment. To differentiate between traditional and Cheers type proas, Newick coined the term Atlantic Proa for proas with rigs, rudders and accommodation in the windward hull. By default, traditional proas scored the prefix, Pacific.

Cheers was schooner rigged, with heavy, wooden, unstayed masts. She was narrow by today's standards at 4m/13', had a conservative sail area and was a pig to shunt (more later on this term). She also had inadequate freeboard at the bow, making for dangerous running in big seas or strong wind. Despite these faults, Cheers showed what could be done and started a rush of proas, mainly by the French singlehanded crowd. These 2nd generation boats suffered a rash of misfortunes, mostly caused by sailors running before they could walk. After numerous capsizes and DNF's, they were banned from short handed yacht races in Europe.

This was similar to the experiences of early cats and tris, although compressed into a much shorter time period, and with the added pressure of very rapid development of other multihulls making the proas look relatively slow. An exception to this was Crossbow, the 60' proa which held the world speed sailing title of 31 knots in 1975. Crossbow was very specialised. It only sailed in one direction and had to be towed back after each high speed run. There was also an 18m/60' long by 24m/80' wide aluminium proa built for the Rhoute de Rhum singlehanded transatlantic race in 1982 . This boat had a single beam supporting a waterballasted windward hull. The beam could be raked aft to keep the bows up in hard reaching conditions. The maiden voyage was out to the race start, and the skipper inadvertently (possibly with an eye on the gales forecast for the first night) released the rope which held the beam in place. It folded in against the lee hull and the boat capsized.

Cheers is being refitted by some French enthusiasts and should be sailing next northern summer. I have no idea what happened to Crossbow, but suspect it is sitting in a shed somewhere in Eastern England. The French monster has, unfortunately, probably been melted down for scrap.

After the ban, interest in proas died out apart from the Pacific Islands where life carried on much as before, although outboard motors replaced sails on a lot of boats. Recently however, there has been an upsurge in interest, mostly people building replicas of traditional proas using modern materials. These tend to be more efficient than the traditional boats, but still have many of their shortcomings. They lack righting moment without large crews, their crabclaw sails tend to be lousy upwind, and because the masts need to be moved from one end to the other, they are slow, cumbersome and dangerous to shunt.

A few people have appreciated and used the reduced stress and materials inherent in proas to build and cruise cheaply. Among them are a couple of French cruising proas sighted in various locations around the tropics, but information on them is hard to come by. Russ Brown (Jim of Searunner trimaran fame's son) has designed, built, and cruised extensively in Pacific proas, although he is loathe to sell plans or to encourage others, perhaps less skilled, to follow in his footsteps. His current boat, Jzerro spent last winter in Brisbane after being cruised from Seattle via Tahiti and Noumea.

One of the most travelled proas is in fact Australian. Designed and built by Blaz Kokor in 1980 , About Face cruised the East coast of Australia, before being bought by it's current owner, Ted Lamont, who cruised, frequently singlehanded from Tasmania to Perth, a journey of some 5,500 miles. About Face was originally an Atlantic proa, but is currently being converted to a Harry type.

Another enthusiast in Australia is John Pizzey, of Brisbane, who has been experimenting with both racing and cruising proas for many years. His biggest boat, Pi is an 11m proa with a single genoa rig which successfully completed a Brisbane Gladstone race. John has since designed and built Flight, an innovative 6m/20' trailerable proa with a hydrofoil in the windward hull which enables the hull to be controllably flown without fear of capsize.

One of the theorists who appreciated the advantages of a proa was Joe Norwood, who wrote about them in his book High Speed Sailing. Norwood appreciated that Atlantic proas placed relatively high stresses on both the masts and the beams, and that these stresses could be reduced by placing these components in the lee hull, as in the Pacific proas. Unfortunately, he confused the issue by adding the complications of hydrofoils which worked in both directions, and the theoretically impressive, but practically very draggy, pyramid rig. None of his proas were built.

What all these proas had in common was that to a greater or lesser degree, they were slow (frequently built to trimaran specs, not appreciating that the loads on a proa are far lower), and had rigs and steering which made shunting far slower than tacking on a conventional craft. Until these obstacles were overcome, proas were never going to be taken seriously.
I built my first proa in 1992 using stitch and glue ply, an alloy mast and a bewildering variety of steering combinations. At 5m/16' long, this was competitive with Lasers and slow beach cats, and taught me many lessons about sailing proas. It was followed by U, a 7m/24' proa with carbon/foam hulls, carbon mast and beams and again, a bewildering variety of steering combinations. Weighing only 150 kgs/330 lbs in sailing trim, U was quick, but was never developed anywhere near it's potential as I kept experimenting with different ideas. U suffered from 3 different rigs, 3 beam arrangements, 2 windward hulls and a chopped down leeward hull, none of which were ever seriously optimised.

Both the 5m prototype and U used a ballestron rig. This is a rig where the boom is extended forward of the mast and has the jib tacked to it's forward end and sheeted to a track just in front of the mast (see photos). The forces of the jib and the main balance each other out, resulting in a rig whose angle of incidence is adjusted by one lightly loaded sheet. Known as the AeroRig in the UK and USA and the EasyRig in Australasia, this rig is excellent for any boat, but for a proa is the difference between a 2 minute shunt with lots of hard work and an almost effortless 10 second one.

The steering/leeway reduction conundrum was far harder to solve, but eventually simplicity prevailed, and two balanced rudders were used, of a size which eliminated the need for centreboards. They have very low steering loads, and can be used individually or together.

These boats were both Pacific proas, and sailing them required a fair bit of body movement to keep the windward hull just airborne for maximum speed. This was obviously not the answer for a cruising proa. But then, nor was an Atlantic proa with a highly loaded rig and beams the answer for a lightweight, cheap, easily built boat. The solution had to be to combine the two, by placing the rigs and rudders in the lee hull, and the accommodation in the windward one. The masts could then be stayed to the ends of the beams, thus reducing the bending loads in both, the lee hull could be as long, low and narrow as possible, and the windward hull could be, within limits, whatever size and shape was required to fit the accommodation. Thus evolved the Harry proa, after a lot of sometimes heated discussion with traditional proa aficionados who wanted nothing to do with boats which were ballasted to windward by anything other than crew.

This perfectly logical solution was undoubtedly thought of by many people, but never tried, mainly because of a conviction that the added weight in the windward hull would cause the boat to luff head to wind as soon as it started to move. This has not happened, a trait I attribute to the 2 large rudders, the hull shapes and the balanced rig. Even under main alone, all my boats have been able to shunt and sail successfully.

To test the theory, I built Harry, a 12mx 6.5m proa with full standing headroom, 2 double bunks, galley and toilet in the windward hull, rig and rudders in the leeward one. Built of bending ply * and epoxy/glass, Harry was an incredibly easy boat to build and sail. I could shunt single handed in 8 seconds. It was also fast, easily achieving wind speed, despite, once again, never being optimised. Harry was another experiment, on which I tried various rigs, hulls, beams and rudders. Despite only weighing 650 kgs, it was incredibly tough, withstanding being blown off 500mm high blocks in the boatyard, and later being washed up onto a beach by waves 'too big to launch a dinghy through' and pounded for three hours.

Just after I modified Harry to try a single beam layout, we moved to Perth and a trailerable version became necessary to sail in the river and the ocean. Harrigami (Harry + origami) was designed as a folding, trailerable proa with accommodation for up to 4 people for weekend cruising and racing, with the potential to race offshore. It also had to be very cheap and, due to my rudimentary building skills, easy to build

Why a Harry proa?

Quite simply, proas are the best possible boats for their speed, weight, cost, building time or accommodation. For example Harrigami in sailing trim weighs 550 kgs/1,210 lbs, contains $20,000 worth of materials, was built in a leisurely 450 hours and has room for comfortable weekend cruising with reasonable amenities. Time and cost details are in the accompanying spreadsheets. With 31 sq m/334 sq' of sail, it easily achieves wind speed up to 16 knots of breeze, despite less than perfect sails, which have been recut numerous times for the various rigs.

Harry proas have the minimum possible amount of structure. Cats and tris both tack. Therefore they see loads from both directions, and have to be built to withstand these. On any given tack, both are carting around a lot of extra boat, solely so that, on the other tack, they will work. Eliminating all the extra bits of boat results in a substantial weight loss. This means that a proa can have a far smaller rig for a given power to weight ratio, which further reduces the loads.

Specific advantages of a Harryproa are:

Light weight.

All the sailing loads are concentrated in the lee hull between the beams, so the rest of the boat can be built very lightly. There is no more boat than is actually required. The lee hull is long, low and narrow, similar to an oversized trimaran float. The windward hull can be designed to fit around the accommodation, with no concessions to rig, centreboard or rudder location. It can also be a lot wider than a conventional multihull hull. Harrigami in empty sailing trim weighs 550 kgs/1,210 lbs. Payload is 500 kgs, although overloading it is not a problem. It would be a little slower, a little more stable and maybe a little wetter.

The material weights are listed on the accompanying spreadsheet. It would be possible to build a Harrigami at near half the weight, using exotic materials and techniques. Because the boat is so light, the rig can be correspondingly small, and lightly loaded. This is helped by having a very wide staying base, and a rig and beams that are only loaded from one side. The lightweight is not achieved at the expense of strength. Both hulls are heavily reinforced where necessary (mast beam and rudder locations), and the furniture and cockpit in the weather hull are integral parts of the structure.

Easy to build.

Harrigami took me (rudimentary boat building skills, though a bit rough) 450 hours to build the hulls and beams to painting stage. The construction technique is the well proven strip planked timber (generally cedar, although Harrigami is Kiri, which is both lighter and cheaper, see sidebar) with fiberglass in epoxy on each side. Wood is an excellent structural material, and encapsulated in epoxy should last indefinitely. It is quick to build because there is so little of it, and very few difficult shapes. Set up costs are very low, (a couple of sheets of mdf and cheap pine planks) only basic hand power tools are needed, all the work can be done single handed and repairs and alterations are exceptionally easy.

The hardest to build part of any hull is the bow, made worse when it needs to be strong enough to support forestay or cross beam loads. Proa bows are only there to keep the water out. Therefore, the planking can be terminated at a substantial bulkhead 800mm/26" inboard of each end, and polystyrene foam, shaped and glassed over is used for the ends. This makes for much easier building, positive buoyancy and an excellent fender in a collision. The lee hull has polystyrene ends plus 5 watertight compartments.

Easy to sail.

The rig is a ballestron so there is no deck gear. No tracks, winches or muscle required. Multipart block and tackles tension the halyards and the outhauls. For racing, a separate tackle is used for mainsail leech tension. The jib is sheeted to a track just forward of the mast. There are just as many strings to pull to achieve optimum performance as on normal boats, but none of them are highly loaded. Proas don't tack, they shunt. In the case of harry proas this involves releasing the mainsheet, turning both rudders through 180 degrees and sheeting in the main from the other end. In reality, the rudders rotate automatically as soon as the boat starts to move. On Harry, shunting single handed took 8 seconds from sheet release to sailing on the other tack. Shunting is a very easy skill to learn, particularly for beginners, as the wind is always from the same place so there is no disorientation while changing sides.

The mast is keel stepped and sized to withstand normal sailing loads, and is strong enough to fly a hull if caught aback. This gives the ability to tack normally in light-moderate breezes, which is very handy for short tacking up marinas or narrow channels. The 2 rudders in the lee hull provide amazing maneuverability. Harry turned in it's own length at 7 knots with a 6 hp outboard. In fact, the rudders are so potent that I tend to tie off the front one and only steer with the aft one. However, when approaching or leaving a marina berth they can be used in tandem to direct the boat almost sideways. In theory, the same technique can be used upwind. In my experience, this takes a lot of care, but in tight situations (in a leebow situation or jamming to reach a mark) it is very handy. The ability to sail backwards, under perfect control should also make for some fun at race starts. Because a lot of Australian sailing is done off beaches, Harrigami's rudders are liftable.

Low cost.

Harrigami hull and beam materials cost $AUS4,500 in mid 2001, see attached spreadsheet. The mast is carbon, built by me for Harry. It is heavier and bendier than optimal. A correct mast would cost $Aus7,500, although we are currently experimenting with a low cost, labour intensive technique for amateur builders which will reduce this substantially. The rudderstocks are also carbon, but are easily built. I have built most of the fittings (blocks, chainplates, jib sheet track, main outhaul track, hounds, masthead etc) on Harrigami. Although they add a bit of time, they save a little weight, a lot of money, and give (me) enormous satisfaction. There is no metal on Harrigami except for thimbles in the sails and a couple of bolts and blocks which I have yet to replace with composites. Apart from the mast and rudder stocks (carbon), sails, rigging (2-8mm spectra) and tramopline deck everything is either wood, epoxy or fibreglass. Total materials cost to sailing stage (including timber. ply, glass, epoxy, sails, carbon for mast and rudders, running rigging, paint and fittings) is $20,000, including plans, excluding tax and freight. Detailed, easy to follow plans for amateur builders cost $3,000 (plus GST in Australia, Nov 2006)).


Safe.

As well as the advantages of a small rig and low sheet loads, harry proas are very safe in high winds. They do not have to build or maintain speed to tack nor bear away down wind and waves to gybe. They never get caught in irons. Shunting is always a controlled exercise, which can be stopped or reversed at any time. Stopping involves releasing one lightly loaded sheet. Reversing to pick up a man overboard is a simple operation, as is controllably stopping to retrieve him. To reduce, raise or lower sails, the sheet is released, the rig weathercocks and the crew never leaves the area around the mast. This can be done on any point of sail. In the unlikely event that the boat is caught aback, the rig automatically weathercocks, facing into the wind. The rudders are reversed and you sail away. The ease of the maneuver has to be seen to be appreciated. Because the rig is balanced, there is no chance of damage in an accidental gybe, and because the stays are only to windward, running by the lee is easy and safe.

Harrigami has positive righting moment to about 70 degrees of heel, depending on weight distribution. At this angle, it is unlikely there will be enough force on the sails to heel it any further. If it was to capsize, the sealed mast and the large box section boom, both watertight, will prevent it going further than 90 degrees. It can then be righted by lifting the jib end of the boom, which immerses the mainsail end and forces the boat upright. Alternatively, the boat will drift until the masthead points into the wind, at which time the trampoline windage will flip it up. Fore and aft capsize is possible, but unlikely due to the low rig, low hull drag (no forebeams, rigging, or bowsprit to trip over) and buoyancy in the elongated bow.

Fast.

Harry proas have a high power to weight ratio, low wetted surface, long narrow waterlines and relatively low windage. However, they also have a very high righting moment as most of the weight is always in the best possible place. For this reason, overall beam is lower than on most cats, further reducing loads, weight and cost. In direct contrast to most racing boats righting moment can very easily be augmented by carrying more food, wine, water, or cruising gear!

Comfortable.

The crew sits facing the rig, with their backs to the wind/rain, so they stay sheltered with an unimpeded view of the sails. Because Harrigami is so easily sailed, and there is no moving around required from the crew, Harry proas are very appealing to the wives/husbands who want to be with their husbands/wives on the boat, but do not want to do anything apart from soak up the sun, watch the scenery and perhaps make the occasional cup of tea, all of which can happen with the boat in full racing mode.


General:

Harrigami is 10.5m long, 5,25 wide, weighs 550 kgs in sailing trim and has 31 sq m of sail area. The rig was originally on Harry but was cut down to allow for the smaller boat, and the stronger winds in Perth. The weather hull is set up for weekending for my wife and I, with a large double bunk, portapotti and, when I get round to it, a shower. . The galley is large, light and airy with a hatch above both it and the bunk. A two burner stove, icebox and plenty of shelf space make it an easy spot to cook in. It is two small steps from the galley to the cockpit. There will be a fold down table opposite the hatch with a seat on each side.

The cockpit easily seats 4 adults on ergonomically designed seats with closed cell foam padding. The knotless trampoline is very easy on bare bodies and at 3m square, there is plenty of space for kids and extras to sleep. The beams are 300mm wide and make very comfortable seats, plus a place to hang the outboard.

The carbon/ply wing mast is 11m high and is keel stepped. The ballestron boom is ply, glass and timber. Both could be a lot lighter.

I am not a fan of show room finishes for boats. Consequently Harrigami's hull were faired with a 250mm/10" grinder with 36 grit paper on a soft backing pad. After glassing, the weave and overlaps were filled with Q cell bog and given the same treatment. Below the waterline was bogged and torture boarded in the conventional fashion, above the waterline was given a coat of primer, then a couple of coats of gloss. The decks were painted with pale blue non slip, and a couple of arty friends let loose with some yellow and white paint. The effect is pleasing and covers any unfairness extremely well. The topsides were to get the same treatment, but Ultrasol sunglasses offered a sponsorship package, so we ended up covering a lot of the topsides with stickers, at the same time covering any imperfections.

Sailing:

Harrigami is phenomenally easy to sail. The rotating rig enables the sails to be pulled up with the rig facing the wind, regardless of the direction the boat is heading. . There are no spreaders or shrouds for it to foul on and because of its relatively small area, hoisting is easy. Once hoisted, the sails are controlled by a single sheet to the aft end of the boom. Because the rig is balanced, this sheet is very lightly loaded and needs no additional purchases, or winches. The jib sheets to a track on the boom forward of the mast and is self tacking. To shunt, the mainsheet is released, and the rig swings head to wind, automatically taking up the slack in the new mainsheet. The crew sheets on a little more and the boat stops and heads off in the other direction. As soon as it is moving, the rudders reverse automatically. The sail is trimmed on fully (a couple of metres of lightly loaded rope) and you are sailing again. In reality, this is even easier than it sounds. Shunting is used both upwind and down. Against a conventional multi tacking, very little is lost. Against a gybing multi, the loss is noticeable. Harrigami has phenomenal maneuverability. By angling both rudders, it is possible to steer the boat almost sideways.

Launching:

Harrigami's hulls sit on the trailer in 2 cradles with sideways mounted wheels (see photo). Ramps are fitted to the side of the trailer and the leeward hull rolled down, controlled by the 4:1 trailer winch. The mast is then fitted horizontally into the boom and the hull. The hull is winched upright using the beams as a lever. It is far less stressful than raising a stayed mast on a normal trailer sailor. The beams are then located under the bunk overhang and pinned in the middle, prior to rolling the lee hull sideways off the trailer. Using the jockey wheel for leverage, the trailer lifts the entire boat on the beams and it is backed into the water. This sounds harder than it is, although it is still a fair bit of work, taking me about 5 hours single handed. Improvements to the system and experience with it will reduce this. Still slow compared to the Farrier system, but it is a lot lighter and cheaper. The trailer was bought second hand for $850, plus a carton of beer for modifications. A custom trailer would make launching/retrieval easier, but costs about $3,000.

Performance:

Harrigami is as easy to sail as it's predecessors. Top speed so far is 16 knots (by gps) in 15 knots of breeze, (Bureau of Meteorology). It tacks through just under 90 degrees and is a delight to sail, particularly singlehanded. Boats with similar comfort and cost don't get a look in. Sea trials will continue over the summer, as will tests to demonstrate it's near uncapsizability, and recovery if it should happen. These should be the subject of a later article.

Harrigami is versatile. It would be cheap and easy to have a second (low windage) windward hull for serious racing, or at the other end of the scale, a fully enclosed pilothouse. Alternatively, the lee hull could be a lot longer,(easy enough to extend it by adding segments to the hull) and the rig a lot bigger. At some stage, this would necessitate water ballast, and/or longer beams.

Harrigami has shown that cheap, spacious, fast, easy to build and sail, and trailerable can all be achieved in the same boat The next step is to explore how fast it can go. This winter I am building a new mast, experimenting with a technique that will make carbon masts an easily built proposition for an amateur builder at a materials cost lower than an alloy extrusion. If this is successful, it would be fun to take Harrigami across to Sydney for AMOC in October. This will be an expensive exercise, dependant on sponsorship, selling a crew position (top offer so far is $800), or preselling the boat before we leave. Anyone interested in any of these propositions, please drop me a line.

Harrigami lives in Perth. Anyone wanting a sail should feel free to give me a call.

Rob Denney
13A Devon Street Swanbourne, 6010 Western Australia

Ph 08 9284 3483


About the author:

Rob Denney is a very experienced multihull sailor with 6 Sydney Hobart's (fastest time, 3rd fastest time, 2nd on corrected time), 6 Brisbane Gladstones, (fastest time, record time, 1st, 2nd, 2x 3rd on corrected time), numerous Atlantic, Pacific and Mediterranean deliveries and 2 big cat capsizes to his credit (debit in the case of the capsizes!). He is also an adventurous and innovative designer with an ultra lightweight racing cat, windmill powered boat, "free-to-pitch-hulls" cat and sundry proas to his name. He is a strong believer in minimising weight and costs and is very firmly of the opinion that a designer should test radical ideas on their own boats before selling plans to others.

*A remarkable plywood, with 2 very thick outer veneers, and a thin middle one. It can be bent to a 100mm radius. Available from Pacific Boatcraft.