Why a Proa?

The idea of building my own boat is something which has been at the back of my head for a long time. As I was learning how to sail, it was clear to me right from the start that I wanted to get into multihulls: they are lighter, about twice as fast, have very shoal draft, and if you build them yourself, are also cheaper than a monohull. These attributes are particularily true of a proa. A proa is a type of multihull which has one large hull (the vaka), and one small hull (the ama) connected by beams. For comparison: a catamaran has two large hulls, and a trimaran has a large hull and two smaller ones. One of the main advantages of the proa is already apparent from this: it’s less work to build than a catamaran or trimaran, because it only has one ama, and usually a very small one at that.

The Tepukei is a special type of a pacific proa from the Solomon Islands. This particular one is on permanent display in the Ethnological Museum in Berlin. I went there to see it back in 2012.
The Tepukei is a special type of a pacific proa from the Solomon Islands. This particular one is on permanent display in the Ethnological Museum in Berlin. I went there to see it back in 2012.

Some very unique handling is required however, because unlike all other types of sailing craft,¬†proas cannot tack or gibe, i.e. take the bow (or stern) through the wind to change direction. Pacific proas always keep the ama on the windward side, essentially a counterweight to prevent the boat from tipping over. There is also a variant of the concept called an Atlantic proa, which always keeps its ama to the leeward side (Dick Newick’s Cheers for instance). Regardless of the type of proa, if you want to change the tack you are on, you have to perform a maneuver called shunting. To shunt, you go on a beam reach and stop the boat, you then rotate the mast, sheet your mainsail in toward what was previously the bow, and put a new headsail up on the old stern. The boat is then sailing ‘backwards’. A proa has a bow on each end, and also a retractable rudder on each end, so there is no fixed bow or stern, no front and back, only windward and leeward.

Shunting a proa, going from starboard tack to port tack.
Shunting a proa, going from starboard tack to port tack.

I know that the shunting maneuver sounds tedious, and it can be, but with a rotating mast (like on a beach catamaran), and roller-furling headsails a shunt can be performed very quickly. Since the boat is very light, it also stops and accelerates rapidly, which helps keep the maneuver short. If the waves are steep you do have to time it right though, and you have to be careful not to let the boat luff up too much after the shunt, or you risk getting caught in irons. Proas also have the lowest overall righting moment and moment of inertia of all the multihulls, so if you put big sails up, especially on a small boat, then it’s a constant balancing act to keep the boat level.

So why bother with all this? To save weight, reduce loads, and greatly reduce the cost of the boat. Having a only one ama means that compared to a trimaran you save yourself an entire ama and a set of beams, you don’t have to build them, you don’t have to carry them around, and you don’t have to pay for them. For a pacifc proa you also drastically reduce the loads on the structure, since the ama is generally just skimming over the water (the force of the sails if trying to lift it up after all), instead of being pressed hard into every wave like a trimaran would. If you run a shroud from the masthead to the ama, then the beams don’t even have any siginificant bending loads on them, allowing you to make the boat lighter still.

The intricate connecting structure and the sealed deck are characteristic of the Tepukei.
The intricate connecting structure and the sealed deck are characteristic of the Tepukei. Traditional proas have amas made out of simple logs, which have a very low volume. Modern proas generally have much more voluminous amas, to prevent capsize if the boat should ever accidentally be tacked or gibed.

The tradeoff you make with a proa is that handling the boat is a little more tricky, in most cases it’s not quite as fast as a trimaran or catamaran of equal length, and the cabin is generally smaller. A proa is the least amount of ‘boat’ that you can have for a given waterline length. It definitely provides the best performance and seaworthiness per euro of invested money though, and that’s why I chose to go down this road. A comparable trimaran or catamaran would quite simply have been too expensive and too large a project for me, but a proa lets me get out there on a fast multihull, even on a ‘shoestring’ budget of a few thousand euros. I think it will be fun to sail, and allow covering large distances with ease, so that I can really get out there and see something of the world. That’s what this is all about.

Building a voyaging proa on a student's budget