• Why are Harryproas so cheap and light?

    Why are Harryproas so cheap and light?
    There is no more boat than is required. For example:

    1. Only one hull needs to be long enough to maintain fore and aft trim and allow for the higher speeds extra length provides.
    2. The lee hull between the beams resists all the loads that are imposed on a catamaran with forestay, sidestay, traveller, rudders and daggerboards. The area on both boats needs to be very strong, but on the harry it is less than 25% of the surface, on the cat it is 95%.
    3. As much as possible, furniture (bunks, galley shelf, cockpit seats, etc) is built into the hull so it does not need to be laboriously cut, fitted, filleted and tabbed in place.
    4. The rudders are oversized so that daggerboards, daggerboard cases or keels are not required.
    5. Chandlery is expensive. Where possible, harrys avoid it. Where necessary, it is often possible to build it yourself. Metal on a boat is heavy, acts as a local stress raiser and is expensive. Composites are none of these, and can be easily applied by the builder. Instructions are included in the plans.

    Less boat means less materials are required than for a boat with similar accommodation which has to work with the wind from either side. A lighter boat gets by with a smaller rig and motors. The cruising rigs are large enough to not need extras, and automatically depower so that extra headsails and furlers are not required.

  • Which is the best rig?

    The best rig for a cruiser is simple, weatherly, light, low cost and low maintenance. As some of these are incompatible with each other, there are many combinations possible. On harrys, the best combination is either balestron or mainsail only schooner, both mounted on unstayed carbon masts. The balestron has lower sheet loads and is a little cheaper. The schooner allows more versatility in balancing the boat (especially useful for self steering and while learning to shunt) link to shunting section and opens up the lee hull.

    The plans include how to build the masts and booms using a simple mould process. They are built in two halves and are about 10% heavier than a mast built in a one piece mould, which we can supply if required.

  • Where are the daggerboards?

    Daggerboards are very aptly named when they hit something at high speed. If they are not to slice the boat open, the dagger case needs to be extremely strong. Fitting them is arguably the most difficult part of building cat hulls. They also take up interior space, are difficult to keep growth out of and are draggy. Tilting centreboards don't have the potential to slice the boat open, but have increased amounts of all the other problems. Fixed keels and asymmetric hulls solve the problems but at the cost of performance.

    Harry's use oversize rudders to handle all the leeway resistance. They have the added advantage of making the boat easier to steer. To be successful, proa rudders have to work in both directions, kick up in an impact and be easily liftable for shallow water/down wind sailing. Ideally they should not involve holes in the hull below the water line. The current solution to these very contradictory requirements is to mount the rudder blades on the beams in cases. The cases allow them to be lifted, the mounting on the beams allows them to kick up in either direction. On boats where the beams are too far inboard, a stub beam is fitted.

    This is an ongoing process and there is no best answer. The three latest boats all have very different solutions, due to the different requirements.

  • Why use infusion and how does it work?

    Infusion is the cheapest, easiest, quickest, lightest way to build hulls. It is also the least messy. The skins and core are laid out dry in a mould or on a table. You have as much time as you need to get everything cut and positioned accurately. The laminate is then covered with peel ply and/or perforated plastic sheet, a distribution medium (looks like shade cloth) and a plastic sheet which is taped to the mould to make it airtight. A plastic tube with a tap on it is plumbed into the bag and a vacuum pump (~$150) sucks all the air out. The end of the tube is placed in a bucket of mixed resin/hardener and the tap opened. The resin is sucked into the laminate and 40 minutes later, whether the job is a hatch or a 100 sqm/1,075 sq' hull, the job is finished.

    A properly infused laminate will have about half as much resin as cloth. A hand laid laminate about twice as much. The only resin wastage is the resin in the distribution media and a small amount left in the bucket. The infused laminate will be mould surfaced on one side and near smooth and fair on the other, so there is far less filling and fairing. The mould/table does have to be built, but as long as the shapes are simple, this is not onerous.

  • When would you not infuse?

    For small, simple jobs vacuum bagging will be quicker.  For rough/rush jobs, hand laminating is the way to go.  For one off complex shapes, such as compound curves, the infused panels can be cut and shut, as Derek Kelsall does with his KSS system or they can be built by strip planked foam/wood.  On recent harry's, there has been a concious decision by the owners to eliminate compound curves to make the build quick and easy.

  • Which resin system is best?

    Epoxy and vinylester are both excellent for infusion.  Ve is about half the price, but smells.  All secondary bonding and laminating should be epoxy.

  • Does infusion speed up the rest of the build?

    Building the hulls is usually a small part of the overall time, regardless of the method. Fitting them out and finishing them is a large part. Because there is unlimited time to prepare an infusion, it makes sense to include as much of the fit out work as possible. On harrys, this includes filleted landings for bulkheads and shelves, rebates for windows and hatches, matched male and female joins, fitted hatches, extra laminate where required, decorative finishes and areas with more or less laminate or core to provide a specific bent shape.

    The aim is to have a boat which, post infusion, requires no secondary laminating and as little filling and fairing as possible. The weight, time and cost saving from this is enormous.

  • I worry that Harry proas are too light for coastal/offshore cruising.

    Harrys are light, but are not lightly built.  The laminates are engineered to take the loads that the boats will experience, plus large safety factors.  They are light because they are the least boats possible and the loads are all concentrated in a relatively small area, which is very strong.  Adding extra weight to a structure that is already strong enough will not make it any safer offshore.  Quite the opposite.

  • Can anyone sail the proa who is used to conventional sailing?

    Learning to sail a harryproa is far easier than learning to sail a conventional boat, as you always sit to windward, so there are no orientation problems. Shunting is very simple to learn, and although there are ways to mess it up, these are far fewer, and far easier to correct than those involved in tacking and gybing.

  • How do you reduce the sails?

    With the unstayed masts, the first reef is automatic as the masts bend.  Further reductions are done by slab reefing the main and/or jib.  Because the masts are free to rotate, this is best done by dumping the sheet which stops the boat.  The reefs can then be taken in at your leisure, without excess motion or spray.

  • Is it possible to use headsail furling?

    Yes, but I dislike the expense, weight and possible problems. This is one of the reasons for switching to the schooner rig. And before you ask, in mast furling is a definite no no, in terms of weight aloft, expense and safety.

  • Can you heave to?

    With ease. Release the sheet, turn the rudders 90 degrees and the boat is as solid as a rock. Drop the sails, and lift the foils and it would take an enormous wave to tip it over.

  • Does the boat naturally come to lie a-hull leeward hull to leeward when left alone?


  • What happens if you are caught aback?

    The sheets lead from the boom to the cockpit so there is nothing stopping the booms from weathercocking, which causes the boat to stop if the wind is from the “wrong” side.  If the caught aback happens upwind, the rudders are simply rotated, the rig trimmed on and the boat sails off on the new tack.  If the caught aback is a major sudden wind change, the procedure is the same, but usually involves sailing downwind and gybing back onto course.  With the unstayed rig, gybing is much less violent than it is on a stayed rig as the boom  is not stopped by the stays.

  • What kind of sailing motion does the boat have in waves?

    Very easy.  Harryproas are much less prone to pitching than cats as the rockerless hulls have very high prismatic coefficients (the ratio of volume in the ends to volume amidships) and all the weight is concentrated amidships, which is also the pitch axis and the location of the crew.  The rig also has a lower centre of gravity than a stayed rig.  Sailing upwind, the bows of the hulls tend to meet the waves at the same time.  This results in a monohull like motion (without the heeling!) rather than the corkscrewing motion typical of a catamaran.

  • Assuming adequate seamanship can the boat be sailed in winds in the 20-25 knot range without overly stressing the structure or 'the nerves'?

    Absolutely. The boat is engineered to withstand all sailing loads up to capsize, with very healthy safety margins. The unstayed masts make the rig very forgiving.

  • How safe is it to fly the windward hull on a Harry proa?

    None of the cruising boats should ever fly a hull, except with competent crew pushing hard and tending the sheets.

    If the hull is inadvertently flown, the rudders become less effective, and the boat slides sideways, dissipating the wind force. Harryproas have positive righting moment until 75-85 degrees of heel, by which time, the wind is blowing almost straight across the sail.

    Of course, this does not allow for waves or the wind blowing on the lifted hull, so it is not a guarantee.

    Racing harrys should always be sailed with the windward hull just above the water. The reduced wetted surface increases the speed, but nowhere near as much (as a percentage), than the same action on a cat or tri as the windward hull is so much smaller and has no rudders or boards.

  • How is the harryproa in bad weather?

    In bad weather they are similar to any other multi, very stable. But with the advantage of being able to lift all the underwater foils, leaving you with a huge raft, drawing less than 300mm/12”. This would be almost impossible to capsize by wind and wave action. Add a parachute anchor and it is even less likely.

    Seaworthiness is as much about the crew as the boat. A well rested crew that is not scared or endangered will make far fewer mistakes than a tired one who is afraid to go on the foredeck. Harryproas are very safe and easy to sail. The crew never leaves the area between the beams and the hulls, never has to remove/replace sails and can sail the boat from a dry, sheltered position.

    Most bad weather problems are caused by the crew becoming tired or scared. If possible, before it gets to this stage, drop the sails, lift the rudders, go below and wait till the sun comes out again. This is far more pleasant and less likely to result in problems than trying to sail when you are cold, wet and tired. In extreme cases or when you do not want to drift too far, towing a parachute anchor will keep you safe and minimise drift. Deploying and retrieving a parachute from the centre of a double ended boat is far easier than from the bows of a cat, tri or mono.

  • What about the outboard motor?

    There are almost as many motor possibilities as there are rudders. The most popular is a lifting bracket on the beam. It only works in one direction, the same as any other boats' motor. Under normal conditions this is not a problem, although it does halve the motor sailing options. Fortunately, harrys sail well enough to make this a rare problem. On the larger boats, 2 outboards can be used.

    Another solution is a single motor mounted in the middle of the bridgedeck. Manoeuvrability is less, although the two large rudders mounted fore and aft are far better than small stern mounted rudders, so it is more than adequate. Recent boats have saved money and weight by attaching the tender bows to one of the beams and using the tender outboard as the auxillary. This has the added benefit of permitting a much larger tender to be used.

    Electric motors are becoming more popular. They can be mounted the same way the outboards are, or use long shafts under the bridge deck. If the rudders are designed accordingly, they can also be mounted on a slide on the blades to keep them clear of the water when not in use.

  • How do you anchor?

    The anchor is stored on the bridgedeck, which keeps the weight out of the ends.  It also means the person pulling it up is close to the helm so there is no need to shout.  A  roller is mounted on the beam with an adjustable bridle from each bow.  Modern anchors only need chain to provide chafe protection, so have much less than traditional ones.  This saves weight, but also means the sheet winches can be used to up anchor, rather than a dedicated windlass.

  • Are there suitable points of attachment for tying off to a mooring?

    Yes. On the smaller boats a piece of pvc pipe with rounded ends can be glued through the bows just behind the collision bulkhead and a bridle tied onto these. On the bigger boats, deck cleats are used.

  • When tying to a mooring do you use a bridle as you would on a cat?

    Yes, but with different length arms, which works well at anchor and on the mooring.  Performance oriented harrys have wing masts, so they blow around a bit.  This can be corrected by dragging a bucket from the back beam, turning the mast(s) so it is not pointing into the breeze or using two anchors.   Because the boats are so light, the loads on the bridle arms are low.

  • Because of asymmetry of the hulls, how do you use a sea anchor?

    Sea anchor, drogue and conventional anchor all use a bridle with different length arms. It works well.

  • Do you sell Study Plans?

    No, as they are a rip off.  We aim to have everything required on the web site. If you can't find any information,  please e-mail Rob as he will very happily answer your questions: harryproa@gmail.com

  • What if I want a boat that is not a stock plan?

    Make a list of your requirements and email them to Rob at harryproa@gmail.com He will discuss them with you and draw some sketches. He loves doing this, so no charge. Once you and he are happy that it can be done, send an agreed amount of money (usually not far off the stock plans fees) and he completes the plans.

    Alternatively, you can draw the plans yourself or buy a set of stock plans and change them to meet you requirements. In either case, Rob will consult as part of the original fee.

  • What is in the plan set?

    The plans for home builders include comprehensive step by step building instructions for the hulls, beams, mast, rudder, boom, and all the fittings. Our back up service is very comprehensive - as much e-mail, mail or phone advice as you require. In many cases we can also advise on the cheapest source of materials.

    Harry proas are still evolving. Consequently, there may be changes to the design. All plan buyers are informed of these, at no extra cost. We also try to keep owners up to date with areas we are looking at changing, so they can organise their building schedule accordingly.

  • Are there any full size patterns included and if so of which parts?

    Full size patterns for the frames for the strip planked hulls and mast are included, or we can supply DXF files to be cut by a water/laser/router cutter.   With the infused panels it is quicker to draw them from offsets and a batten.

  • When I buy a set of plans, would I be able to get the updates you later add?

    As soon as we are happy with the improvements they go in the plans.  Updates are free to anyone who has bought plans.

  • What is meant by 'built to sailing stage'?

    Sailing Stage means your harry can be taken for a sail. No motor fittings, internal fitout (apart from what is part of the structure) and only enough paint to protect the laminate from the sun.

    Cruising stage means fitted out ready to top up the tanks, buy food, step aboard and take off.

    Racing stage means ready to step aboard and race.

    Cruising and racing stages vary between owners so are very difficult to quote for.

  • What is the "Goodwill Fee"?

    Because harryproas are a brand new boat type, and few have had the chance to sail them, we would like to encourage owners to take people sailing. Anyone who does this for someone who subsequently buys a set of plans will recieve 10% of the plans price.

    In the event of 2 or more owners taking someone sailing, the 10% will be split according to my best judgement. This will be final, no appeals nor ill feeling are allowed. The 10% comes directly out of my pocket, and I reserve the right to curtail it at any time, with due notice.

    It is a goodwill thing, to encourage owners to take people sailing, not a means to pay for your boat. It does not excuse potential customers from the customary obligation to supply lunch and beer/wine/whatever for the owner and his crew!


  • How do I transfer money to pay for my plans?

    Bank details for a wire transfer are"

    Account name: RA Denney

    BSB number: 084 402

    Account number: 049751892

    Swift Number:NATAAU3303MBranch

    Address: National Australia Bank Sunnybank Plaza 14 Zamia Street Brisbane Qld 4109

  • Has anyone sailed a harry on an ocean passage?

    Aroha (12m/40') was sailed across the Tasman in 2010, encountering a severe storm.  Sidecar (7.5m/25') has sailed over 1,000 miles up and down the very exposed Western Australia coast.

  • How do you rig navigation lights on a proa?

    You need 2 sets and switch them when you shunt. One option is to mount them on a folding mast outside the rudders on each end of the lee hull. There are others, depending on which boat you have.

  • Will bigger and smaller harryproas work?

    Size limits are related to reasons such as fitting on a trailer/in a container/in a marina. Within limits, the longer the lee hull, the faster, more comfortable and safer the boat will be. Providing the beam and sail area are not increased, the cost and weight of the extra lee hull is minute in the overall boat.

    The biggest Harry drawn was a 45m/150'ter for The Race. The biggest built is the 20m liveaboard cruiser, Luca Antara in Portugal. The smallest is harriette, a 4.5m/15' harry for kids.

  • Assuming the same space and build quality, why is a harry proa lighter/faster than a pod proa of the Russ Brown or Pacific Proa Company type?
    1. The pod proa needs a lot more lee hull (higher and wider) to house the crew. The lee hull sees far more loads than the weather one, so the extra area of hull must be heavier than the windward hull on a harryproa. This is exacerbated by the extra surface needing more bulkheads, frames and floors to support it. Cutting a huge hole in the side of the lee hull, at the most stressed location, and building a pod onto it increases the loads significantly. This in turn increases the weight and cost. A pod to leeward of the lee hull sees far higher impact and dynamic loads than the same pod to leeward of the windward hull so must be stronger, heavier and more costly. These differences could easily account for 10-15% difference in bare boat weight.
    2. The pod proa has less righting moment as all the accommodation is in the leeward hull. Therefore, as soon as the breeze reaches a certain point, it must reduce sail, or pump water ballast to stay upright. Given that the pod boat is already heavier, then to achieve harryproa speeds, water ballast is the only option. This further increases the weight of the boat. Lee hull accommodation is also wetter and more cramped (must be built around the mast) than weather hull accommodation.
    3. The pod proa does fly a hull sooner than the Harry proa, and in a very narrow range of breezes could be as fast. However as soon as it starts immersing it's pod, it's speed must drop. The pod proa will give some warning of being overpowered by flying the weather hull and immersing the pod. The Harry proa, in the same wind strength has not started to lift the windward hull. Given more breeze, the pod proa will capsize first.

    It should be noted that I think Russ Brown's boats are gorgeous and they were inspirational to me and that these differences are not major. A pod proa would still be a better boat than a cat, tri or mono, it just won't be as fast, or as easy to live in as a same spec Harryproa.

  • Why not use the KSS flat table method?

    We originally did, (link to solitarry) after sponsoring 2 KSS workshops. This was an improvement on the KSS system as it did not require cutting, glassing filling and fairing below the waterline and only had one join, instead of two with the KSS system. However, the shapes available were limited, particularly at the bow on the lee hull, fitting bulkheads in deep narrow spaces was hard work and fibreglass does not bend as uniformly as we would like. There are also limits on the width of the curved section of the hull before foam became necessary. To bend these, then glass them was extra work.

    The solution was to use cheap, flat panel box moulds, which are self aligning, allow a variety of shapes, including variable chine and gunwhale curves and are easier to seal and level than a large table. We still use a flat table for bulkheads etc, but this is rarely more than a single sheet of material.