I've had a few good outings with the laser rig, but I really want to try a shunting rig. A force 4 wind is quite an exhilarating sail at the moment, on the 'proa' tack the front of the ama lifts a foot or two out of the water and we fly along effortlessly. There's a little flex in the aka lashings and there must be a little twist in the hull due to the immense load from the unstayed mast (it's imperceptible) at the front and me sitting about a meter out on the hiking bench at the back.
On the 'trimaran' tack the front of the ama punches through waves, seemingly with little resistance, but it sends a bow wave half a meter into the air - and the centre-board also catches the water and sends it's own spray up high. Fortunately these are both to lee of me, so I can admire the view and stay dry. Unfortunately I haven't taken pictures while I'm sailing.
I've tried flying the ama, and while it can be done, it requires a careful balancing act. If I go to high, the part of the boat that's in the water is tilted under me, and there's no going back. The 3m X 100mm safety ama hit the water with a splash but couldn't support my weight, or right the boat on it's own, but it (and the sealed laser mast) did keep the boat on it's side, and make it easy to right, and I bailed it quickly with a big bucket. Since then I've learnt to tie on the hiking seats and to fly no more than half the ama! This limits me to a force 4, unless I've got some crew for extra ballast ;-)
On both tacks, it's easiest to steer the boat by adjusting the position of the centreboard a little. Fully powered up 'rudderless' sailing feels great! This works best when the board is mounted behind the centre-line, so that putting it down causes the boat to bear away and lifting it up makes the boat round up. I guess that means the rig is a little too far back, but it's much easier than steering with the oar! The oar is great for changing course, but hard to hold an out-of-balance boat. The blade floats, so that most of the blade area in the water is below the centre line, which twists it in my hands. I'll add some weight.
Tacking with the oar is a skill that took a while to understand. First I tip the centre-board right up (which involves moving in from the hiking bench, possibly requiring depowering the sail) and then steer hard upwind. As the boat approaches the eye of the wind, I lift the oar out of it's rest and make one big sweep stroke to push the bow through the wind. Then I move to the other side of the boat, passing the oar behind the mainsheet (and usually hitting my head on the boom). Down goes the centre-board and we're off again.
Unless it's a little windier, then I can't steer and sweep-stroke hard enough to get around and we end up going backwards. It should then be possible to do something clever with the oar on the other side, but that risks tipping over.
Gybing is a similar story, in a force 4 we go around in a big, fast arc. It's very noticeable that having the sail a long way from the centre-line turns the boat, so it's important to keep it in tight and flip it over as soon as possible. If it's too windy to beam reach with the sail in tight, it's impossible to gybe - we just ended up on a flying broad reach with the sail right out and the oar straining to counter it.
So the obvious solution is to sail this boat the way the polynesians did, with a shunting rig. No more tacking and gybing, a shroud to take the load from the sail, and the promise of being able to steer by over-sheeting the sail. I have three old glass/expoy windsurfing masts from a nice chap who was upgrading to carbon masts, a mast foot he also didn't need, and I've made a selection of things to fit in the ends of the mast.
From left to right, the boom jaws (a crude gooseneck), the mast head, the yard tack, the yard head and the boom clew. The first three were carved from an old hard wood doorstep, the last two from an old fence post. I used an
'eight siding gauge' (mine is too crude for a photo, just a bit of wood with two nails and two screws, but it's very satisfying to use) and lots of rasping and sanding.
I put a sheave in the mast head so I could adjust the height of the yard, but then I realised that the shroud and back stays need to attach to the mast at the same height as the yard or there will be a big bending load on the mast. Then I thought I could make a sliding collar where they'd all be attached, but the shroud and stays would have to be adjusted every time it was moved, and I'm pretty sure the mast needs to stay up while I hoist the yard.
I realise that I'm making things difficult for myself here by not following the plans exactly, but the book only has a 5 square meter sail and I've got used to power of the 7 meter laser sail. Hopefully it'll just take a bit of trial and error to work out where everything needs to go, but it really feels like uncharted territory not having measurements for everything I need to make.
In a similar vein, I thought it best to make a practice sail from an old plastic tarp. It's a good thing I did, because sewing is harder than it looks! Here's a close-up of the clew, showing how much I struggled to keep and even speed through the machine, my wonky lines and the number of times the thread broke.
The good news is that even a pretty basic, 45 year old machine has no problems with at least 6 layers of tarp and two layers of nylon webbing.
