Entries | Proas

Samwise - Part 3

Some fairly dramatic changes since Samwise Part 2 (Part 1 is here). The biggest change is that Sam is now a balls out Atlantic proa - rig placed in the windward hull. No faux Pacific, "weight to windward" sham, an Atlantic proa is Sam I am. Larger pics after the jump.

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Canoes of Oceania

Harmen Hielkema has joined the blogosphere at Canoes of Oceania. Harmen designs and builds proas in New Zealand with an artistic eye and an appreciation for prior native art. From his blog:

Every culture with very few exceptions, somewhere in its past has some connection with the sea and a technology for moving or sailing on it. The sailboat was the first machine to give men freedom of motion without harnessing muscle power. Few of us any longer recognize that the sailboat was truly the first instrument which freed us from bondage to the land ... the waka ama, the first sailboat that could move up wind. This invention made previously inaccessible areas of the world accessible to man, ... Neither do we recall, unless our attention is drawn to it that the sailboat was the first machine to achieve powered motion without rotating parts. Bernard Smith, The 40 Knot Sailboat, Grosset & Dunlap, New York, 1963.

Samwise - Part 2

I fleshed out a few scale drawings of Samwise last week. In keeping with the minimalist theme, I'm doing the minimum of calculations. As you can see, proportions have altered a bit - but form follows function. The goal was to make the hull sides from straight ripped ply - 2' wide - easy as pie. The straight ply goal meant the crossbeams buried in the hulls had to go, so now they're lashed or bolted to the deck in beach cat style. The cabin has comfortable sitting/laying about headroom, 2' beam on the bottom. I'm debating whether I need a solid cabin or not. I could see small dodgers fore and aft, and making him into an open sailing canoe.

Still no rudders, as you can see. I'm quite certain the boat will self-steer as if on rails on most courses, and it would be fun to steer the boat by sail trim alone, and no rudders would save a lot of building time and trouble, but still... rudders are nice.

My enthusiasm for the lug rig has not abated. Masts are only 17' long! Read more about standing lugs in this Duckworks article by Michael Storer.


LOA: 24'
Length lee hull: 24'
Length windward hull: 20'

BOA: 12'
Beam lee hull: 1'-8"
Beam windward hull: 2'-8"
Interior headroom: 3'-6"

SA: 220 sq. ft.
Rig Height: 22'-8"

Crab Claw Tests

These are qualitative studies of slender foils and leading edge vortices for sailing craft. The results of these experiments, suffering from improvised input and variable conditions were good enough to inspire further work but produced more questions than answers.

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There and Back Again

Samwise is a minimalist cruising proa, which is really the only kind of proa there should be, IMHO. The only thing not minimal is the performance - the proa’s raison d'etre. The basic idea is reliable and cozy camp cruising in the Pacific NW - where the water is generally frigid and the air is generally tolerable.

Sam’s godfathers include Matt Layden's Paradox and Rob Denney's Harry, while a host of uncles include Phil Bolger, Peter Spronk, Dick Newick and Ralph Munroe. He (all proas are masculine) features simple plywood construction, an enclosed sailing cockpit, plenty of deck space, endless conversations at the dock, and the ability to go there and back again.



The crew helms from an enclosed sailing cabin - which is a nice feature in the Pacific NW and its nearly iceberg laden waters. Laugh at the freezing spray as you drive like an arrow to windward! Mock the waves as they surge impotently against your plexiglass shielding! Unlike tacking craft, proa crew have no need to make the treacherous trek to the other side with every tack. You are always on the good side of a proa.

In the unlikely event of pleasant sailing weather, you can slide open the hatches, or sit atop the flat cabin top, or even sprawl out on the trampoline, catching the sun. The tramp will also make a fine place to pitch a tent for overnighting - if a real double berth is required.

The leeward hull is the load bearer, so it stretches out to 24' of lean, wake-cutting form. The windward hull is the ballast, which makes do with 18' of LWL. Skilled sailors will fly the windward hull at every opportunity. Being flat-bottomed in sharpie style, the hope is that it will plane if given half the chance.

The free-standing schooner rig makes for a criminally low center of effort, while the standing lugs create a powerful yet balanced, easily handled sail that requires no purchase on the sheets - which comes in handy during a shunt. The forward lug is rigged with the mast to windward (its most aerodynamically advantageous position) while the aft lug is set opposite, which moves the combined CE well forward (a desirable thing on a proa).

Leeway is prevented by a central, pivoting leeboard mounted on the leeward hull, and steerage is provided by fore and aft "dagger" rudders. The hope is that in the unfortunate event of a grounding, the deep leeboard will hit first, pivoting gently out of harms way as it stops the boat, whilst leaving the delicate rudder intact. As usual with proa designs, the rudders are sketchy... at best. From model testing, I found a schooner rigged proa such as this will balance and self-steer on most courses by sail trim alone - Sam, by nature, is a virtuous course keeper. Be that as it may, a real cruising boat needs a real rudder. Suggestions are welcome.

The proa's beam is retracted to trailer width via telescoping aluminum beams (as an option, Jim Shanahan has proposed an ingenious hinging mechanism).

Note: This sketch is a cartoon only. No plans are available.

FreeShip Walap

I've found a way to force the freeware boat design softwareFreeship 2.6 to do proas, it may interest proafile readers.

The problem is that such programs assume that the port and starboard sides are mirror images of each other, so you can build a catamaran or a trimaran, but not a proa. Then I remembered that proas *are* symmetrical, only the axis of symmetry is turned 90 degrees.

The trick is simple: begin with the default design, and set the measures to say, 6 meters WIDE and 0.5 meter LONG. the hull will look weird at first, but once you move the control points around, it becomes pretty normal.

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A Primer on Proas

aerohydrofoil Sailboat concept pioneered by Bernard Smith in the 1960’s and described in his seminal work The 40-Knot Sailboat. Smith's analysis of sailboat kinetics led him to a groundbreaking design involving no traditional sail or hull, instead utilizing solid airfoils and buoyant hydrofoils, arranged in a proa-like formation. Many of today's proa advocates credit the excellent proa chapter with sparking their first interest in proas.

ama  Polynesian for outrigger float or log, in common use among multihull designers.

aka  Polynesian for outrigger cross beam.

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Cheap, Capable Cruisers III

JOHN DALZIEL: We seem to have found a few ineluctable limitations as to just how far one can stretch the traditional Micronesian proa so it can meet modern Western demands. With a modicum of care we can stay well within those limits and come out with a good, inexpensive cruiser. We've also seen that there is a fairly clear trade-off point beyond which it makes more sense to build a catamaran than a proa. The question is, where can we take it from here?

MICHAEL SCHACHT: The Pacific proa is unique in that it appears to have near monohull self-righting ability, yet without the heavy ballast. That means it can bypass the displacement wave drag of monohulls - like a cat, and yet it can sail closer to its true potential more of the time - like a monohull. Best of both worlds? Only if you are willing to make sacrifices in other areas (such as extreme length), mother nature can't be cheated.

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Cheap, Capable Cruisers II

John Dalziel: We want several things: good carrying capacity so the proa doesn't get absurdly long, both genuine and perceived constructional simplicity with a minimum of hytek or expensive fittings, and a design with a clear purpose of economical sailing, not yachtie snobbery. So let's look at a few sketches I've made of "similar" boats that fill all the above criteria; a 28' dory, 28' Wharram-inspired catamaran, and three 38' proas. Just how these can be considered "similar," I'll explain a bit later. But for now, all of them have at least one-ton carrying capacity, and are all intended to be built cheaply.

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Cheap, Capable Cruisers I

JOHN DALZIEL: Well, Michael, there are a lot of cruisers out there; where do cruising proas fit in? It seems we have three overlapping categories of cruisers:

• Camp-cruisers or beach cruisers as they are sometimes called, with minimal accommodations and equipment, sailed by one or two, and mostly used on island-hopping or similar short-distance jumps which are often part of longer cruises. There's been a lot of discussion of these on Proa File International, and a few have been built, including my Charles L. Brock and John Harris' Mbuli. Gary Dierking's Te Wa would be at the outer edge of this category, size-wise.
• "Cheap capable cruisers," meaning light-weight, simple boats designed for vacation cruises of 2 days to voyages of several months' duration, larger than camp-cruisers and carrying more in the way of supplies and equipment. I'd put your proa Rozinante and Russell Brown's first proa, Jzero, in this category.
• "Live-aboard cruisers" intended for full-time occupation and longer passages. These can also be cheap and capable, but will have more room for stores and are usually better appointed with the idea that the boat is also a home. There's a few proas amongst these, also, for example About Face and De Jours Millieurs.

But over many years seeing people sail to paradise I've noticed that the majority who get there at a younger age have made the trip in small, cheap, used or sometimes homebuilt boats, seldom ideal for the purpose. Yet they are out there doing it, not just dreaming, and obviously having a grand time. So "cheap, capable cruiser" is a category that interests me quite a bit.

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