Home Crafts & Hobbies The traditional proaboat is given a modern twist

The traditional proaboat is given a modern twist


Ali Wood discovers more about Rob Denney, a visionary designer of proa boats.

Visionary designer Rob Denney’s C50 Air concept. Credit: Rob Denney

New Zealand designer Rob Denney, a boat enthusiast himself, is an avid proa boater.

He skipped his accounting exams at 14 to compete in the Sydney-Hobart Race and has never looked back.

He’s spent his career racing, delivering and designing yachts, among them a catamaran he capsized in a ‘gung-ho’ two-handed round-Britain attempt (the boat, considered a shipping hazard, was destroyed by the Irish Navy) and a 30ft Iroquois catamaran propelled by a three-bladed windmill.

“That taught me a lot about engineering,” says Rob. “We sailed at 6 knots into 20 knots of wind, which I considered a success. It was fun!”

A catamaran being powered by. windmill

Denney’s early windmill design powered an Iroquois catamaran. Credit: Rob Denney

Rob returned to Australia and launched a business selling cedar-strip kit boats, before building his first proa boat in 1995 using stitch and glue ply, an alloy mast and a ‘bewildering variety’ of steering combinations.

His 16ft (5m) proa, which was competitive with Lasers or slow beach cats taught him much about sailing proas.

He experimented with new ideas and changed the rigs of his boats, beam arrangement, steering, and hull size.

“Proas range in size from small boats ballasted by baby coconuts to ocean crossing vessels capable of carrying a dozen people and supplies for many weeks,” he says.

“They were probably the first improvement made to a floating log by early sailors. A second, small log was lashed on a cross beam in order to prevent the main log from capsizing. Rigs were added later when technology allowed.”

Racing proas

The first racing car to become famous was the 40ft (12m). CheersThe race was held in 1968 and the single-handed transatlantic race (OSTAR) came third.

She was notoriously hard to shunt, as she had the rig and rudders in her windward hull.

After her success in Europe, many single-handed proas built by French builders were banned after many capsizes or non-finishes.

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In 1975, the 60ft (18m). Crossbow The boat, which reached 31.1 knots at Weymouth and could only sail one way before being towed away, broke the 30 knot barrier.

Sir Timothy Colman, of the mustard family, was her owner and held the World Speed Sailing Record with his Crossbow Proa designs for many years.

Paul Larsen set the record in Namibia in 2012 aboard the proa Vestas. Sailrocket 2..

Rob has designed a racing foiling prosa for the Volvo Round the World Race In-Port Series.

What makes proas unique?

The difference between proas and ‘regular’ multihulls is that the rig is mounted in or on a hull.

The steering (ie. The steering (ie.

They ‘shunt’ instead of tacking or gybing, so the windward hull is always to windward.

“There are many variations with proa designs, suggesting the ultimate proa is still to be built,” says Rob.

 Denney’s Orbiter 80 can be set up in a number of configurations, including as a medical services vessel. Credit: Rob Denney

Denney’s Orbiter 80 can be set up in a number of configurations, including as a medical services vessel. Credit: Rob Denney

Notwithstanding, he’s had a pretty good crack at it himself.

The prototype Harry It was a proa of 12m (39ft), which he could haul with his single hand in only 8 seconds.

Then he followed up with HarrigamiTogether with designer Mark Stevens we designed a trailerable folding proa. VisionaryA 15m (49ft), version of Harry Built for the Dutch market, this boat is designed to allow blind people to sail.

“These boats were all strip planked timber and had very curvaceous shapes,” he says. “They required a huge amount of filling, sanding and fairing.”

Modern methods

In 2005, Denney co-hosted a workshop with Derek Kelsall, something he recalls as a ‘real eye-opener’ about the use of foam infused on a flat table.

“I built a couple of hulls using this method and further developed it to use cheap flat panel moulds which cut the work required and the weight of secondary laminating for joins and fit-out.”

Steinar Alvestad is one of his first customers. He now uses the new techniques to redraw all boats.

It’s a partnership Rob says works well.

“I send my designs to him in Norway, he draws the plans and makes them look pretty. I have trouble finishing things, but he’s a perfectionist. He fills in all the holes.”

Rob’s website features nine designs, ranging from an E25 trailerable (with optional cockpit), to the EX40 Weekender (with scope for long cruises) or the Orbiter80 cargo ferry.

 E25 is designed to be quick, clean, easy and cheap to build. Credit: Rob Denney

E25 is designed for quick, clean and easy construction. Credit: Rob Denney

All are lightweight, low cost and easy sail.

“The Harryproas are designed to be the most possible boat for the least money, the easiest to sail and the safest,” says Rob.

“Capsizing my boat in the round-Britain focused my attention on safety. I spent 11 hours in a liferaft, so I’ve done everything to make them safe. The sails are low-stress, and there is no foredeck (no foredeck!) The masts are unstayed with self vanging wishbone booms, so the whole rig is an aerofoil without requiring any sheet tension to tighten the leech.”

He explains to me that cats and tris have a large amount of extra boats so that they will be able to work if you switch tack.

These structures are subjected to loads in both directions and must be designed to handle them.

Eliminating all the ‘extra bits of boat’ results in substantial weight loss and means the proa can have a far smaller rig for a given power to weight ratio, further reducing the loads.

Marshall Islands trial

Rob taught the Marshall Islands how to make plywood cargo proas two years ago.

The dying skills of sailing were his motivation to bring back the use of sailing for catching and transporting cargo.

“The islanders had outboards at the time but no-one had shown them how to look after them,” he said.

“There were no spares and petrol was expensive. They ran them till they died then couldn’t do anything.”

A proa boat being sailed offshore

A plywood cargo boat was built in the Marshall Islands. Credit: Rob Denney

After returning, he spent 18 months designing an 80ft cargo trailer.

It cost him $50,000 AUS (£26,740), weighs just 3 tonnes and carries 10 tonnes of cargo.

The success of the cargo ferry concept has led to some interesting spin-offs, which Rob calls ‘Orbiters’ and describes as, “a fast, comfortable sail boat, rather than an over rigged, overweight source of income for repair people at every port of call.”

His website shows some innovative designs including an Orbital University that includes sleeping pods for students, a Medical Services boat with an operating desk for doctors and dental professionals who wish to help remote villages or islands, and also a rapid response boat for natural disaster-hit areas.

“Apart from the beams and the masts, the rest of the space is available to your imagination,” says Rob.

“Instead of mandating a payload and a layout that dictates what you can put on board and the size of the rig required, we are going in the other direction.”

Visit harryproa.com to learn more

Have you enjoyed reading Modern take on the traditional boat proa?

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