Tuesday, May 27, 2008

Queen Prawn Spawns

I am not sure where I first heard about the micronesian or Pacific Proa. I blame it on Wikipedia's article of the day. They had something about the spread of austronesian peoples across the unspeakable vastness of the Pacific, and I had to wonder: what the hell do you use to do that when you haven't yet smelted bronze?

From there I found Tim Andersen's webpage (http://www.mit.edu/people/robot/). Tim Andersen is a hapless adventurer, competent inventor, and loveable junkhound whose utter lack of any sense of personal safety somehow resonated with me. Read his stories if you get a chance; he's a brilliant and very funny writer. I sent Tim's stories of Yucatan proa misadventure to my then-girlfriend Monica. "So this prawn thing is just a really efficient way to drown your girlfriend". Well, from then on I was sold, and the hull had a name: Queen Prawn.

The pacific proa is not appealing because it is dangerous to loved ones but because it is so elegant in concept. It has dynamic lateral balance, which is precisely the axis that a sailboat encounters dynamic force. It makes an awful lot of sense. Besides, if I'm going to build and sail something that looks like a wrecked fleamarket stall, why not make a really fast, weird-looking fleamarket stall?

Once I was finished enjoying myself with Tim Andersen, I moved along to serious thinkers. Gary Dierking seems to have the best handle on hull design, and I grabbed a plan based off his Tarawa hull but executed in plywood, as described here. Sixteen feet (or so) length, twenty-two inches wide and something like twelve inches of draft with three hundred and fifty pounds displacement. Long, skinny, and deep. Aggressive asymmetry to counter leeway and to mayhaps provide a bit of windward creep to help in holding a course when beating. Two chines, about the easiest layout to build. The single outrigger is a somewhat streamlined PVC pipe with the ends clamped shut and epoxied, with about two hundred pounds of displacement, give or take; enough to not sink too quickly when you step on it. Aluminum tubing connects the outrigger to the main hull, and can take five hundred pounds of torque in the middle, which is handy when the wind picks up you, your wife, the outrigger, and whatever cargo is handy before flinging them all into the Gulf of Mexico. "Flying proa" means "effing terrified" in Malaysian.

The various traditional-type proa sail rigs sounded frankly like trouble. The aboriginal crab claw is a great rig for a family of fifteen, which seems to be the minimum crew for safe handling. The Dierking-Gibbons rig involves an awfully big sail flying up over the heads of the crew for several suspenseful, and I suspect mostly tragic, seconds. It also has lots and lots of continuous loop rigging running uninterrupted around the vessel. Interrupt one and you capsize, or, amusingly, take flight. Probably both. I thought the winner was the double sticker used in Mbuli (www.clcboats.com/shop/sailboats/proa/), also known in proa circles as the schooner. This rig, although involving two of everything- two mains, two masts, two sets of rigging- and a substantial decrease in performance, allows the sailor to adjust the center of effort as needed. It also allows the sails to luff, depowered, while I futz with various homemade gizmos and recover family members treading water. I was also interested in the idea of basic steering being done by trimming the mainsails. Sheet in the rear sail to head up, sheet out the rear sail to bear away.

Why did that sound appealing in particular? Well, proa are sort of rudder-challenged, due to the fact that they have no fore and no aft. Since it switches sides every tack, you need to carry a rudder from one side to the other or make all sort of kick up rudder thingies in various places around the boat. With two sails you can mostly steer with the sheets. In theory, anyway. As an alternate I'll program a monster bullhorn to scream "I HAVE NO STEERAGE" at thirty second intervals, and carry enough water to make Texas.

With these loose guidelines in place, I started cutting. The sides began taking shape. It soon became apparent that the last four inches from each side fore and aft was going to be lopped off because I was using two 4x8' panels per side. Whoops.

The sides and the frames are fastened sort of loosely in these pictures. I just put enough tacks in to make it solid enough to move around, which is to say, not very solid at all.
It almost looks okay from this angle.
So much for river cruising. Seen from the lee side, you can see the Queen Prawn is going to draw a lot of water.
Very, very crooked. Have I mentioned how floopsy the structure is? Rails, fiberglass, and addition of the bottom plank will hopefully straighten out the cambers in her sides.