Bulkheads and deck

It has crossed my feeble understanding of how structures work that I shall need something to which to attach the outrigger. After gazing dolefully at it for a while I arrived at the conclusion that my flimsy 4mm bulkhead made of sub-standard plywood is not going to be especially good at conducting strains from the outrigger into the main hull. So I sat down at the drawing board and tried to work out what to do, and the simplest solution appears to be Thick Bulkheads. The bulkheads are surprisingly small when drawn full size, so they can be 12mm five-plies and still not impart excessive weight.

The boys at the timber yard, all of whom enter into any boatbuilding project with unfeigned enthusiasm, had pointed me at some test sheets, randomly selected during a production run, which have a foot cut off two edges to check that the inner laminates are all sound. There isn't much you can do with a seven-by-three sheet so they sell them off for $26, always to boat-building amateurs because everyone else is spending someone else's money and doesn't care what stuff costs.

I used a handsaw, since I've found I can't rely on circular saws and straightedges. And I plane afterwards to a sharp pencil line with a hand spokeshave, since it's more accurate than relying on an actual plane. Which I use with the confidence of knowing that ultimately the epoxy will fill any gaps, and further knowing that every joint will be reinforced with glass fibre, and yet further knowing that out at sea I care more about strength than appearance. I cut four bulkheads; two are for the middle of the boat and will meet and be bolted together to turn it into a long canoe. The two that seal the end decks stand proud of the putative deck and are to have short, stout solid hardwood beams attached to them. To these short beams I propose to attach the outrigger arms. I'm not yet sure how to make the attachment: over in Stephens Bay sits a waka, or outrigger canoe, for four people and I think it's the one I sometimes see a young family paddling of a Sunday morning. Here the arms are attached by nothing more than luggage straps. However a waka paddled on still water with two small children aboard isn't going to be subject to the stresses of a large sail in a lively sea.

In the last few days we had some warmer weather so I started gluing the deck together. I delayed while it was cold and rainy: I want my epoxy to go onto a dry surface, and I want it to harden in the sunshine. First things are the strips that will extend the glued area. I think these are called stringers. Mr. Dierking suggests cutting slots every three quarters of an inch, half-way through the stringers, to allow them to follow the bend of the deck. Did this with a blunt tenon saw, and don't recommend it. Took ages.

Then I went looking for copper nails and found none, nor any fine stainless steel screws, and I ended up with solid brass Phillips-headed woodscrews which were all that's available here. First lot of brass screws proved to be magnetic, and a file revealed a pathetic brass plating. They're only to hold things together while the glue sets, but thereafter they can remain and I don't want rust. Bronze would be better but asking for bronze screws provokes hollow laughter.

After thinking about the wood splitting I made a 2mm spade drill out of a galvanized bicycle spoke, and used it to drill pilot holes. Cheap spokes are high carbon steel and an underrated source of very small woodworking chisels. I even use them for carving or for scraping steel. Left dead-hard (heat to red and plunge in water) the edge is so small that you can sharpen them easily with a diamond file. What did we do before diamond files?

After gluing both surfaces, I started by screwing the pointy end with two screws before bending the stringer. It is a fiddly business and used up five pairs of rubber gloves, which I shall recycle now that I thought of turning them inside-out to let the epoxy harden. Even fiddlier was the attempt to fill all the slots with epoxy by shoving a knife-blade into each one, and I don't think this worked; I think there is only a smear of glue over the top and the slots are hollow, so I shall pretend this was a deliberate weight-saving plan. Tried using sawdust as a filler mixed with the epoxy, too. Not very successful: had to mix in some 'proper' filler with it, though the sawdust-plus-filler was very good at sealing the whacking great gap between the fronts of the stringers.

For the record, I'm using Epiglass HT9000 epoxy, and HT120 filler to mix the glue and HT450 filler to mix the filler, and Epiglass can now jolly well send me a voucher for this gratuitous advert because the stuff's Hugely Expensive. Resin and hardener are measured with two syringes that I keep, wet, in separate empty screw-top honey jars. Mixed with ice lolly sticks, in plastic Thai takeaway dishes. Drips on the floor cleaned up with acetone on tissue, after learning that acetone does clean epoxy.

And here is a 1935 film of making a steam engine. Not even mildly relevant, but it gave me 17 minutes of unalloyed pleasure.

Bulkhead

Well it turned out that hammering wedges into the stitches to move the side planks outwards was a useless idea. Didn't work at all. What did work, and worked easily, was using the planks as a lever, opening them a little, and inserting pointed dowels into the inside stitches. And I didn't need very many either. It was most pleasing. The dowels were made pointy with my newly patented proa-stitch-tightener-conical-wedge-making-machine and if you would like to send me a hundred thousand dollars I will tell you where you can get one. (Clue: pencil sharpener.)

The one end that's now sewn together is a big floppy item, remarkably unlike anything you'd put to sea in. It has to be stiffened into a torsion box with a decked-in end and a wossname - a thingy - all the nautical terms escape me - a bulkhead, thank you. I need to seal each end into a huge hollow box using a deck and a bulkhead, not only to stiffen the structure but also both to contain air as flotation and to remove swampable volume. How much sea will come in is not yet known, but when Graeme came poddling over from next door to see how I was getting on and I started to ruminate on where to step the mast, he recalled that he hoped I was going to start with the Optimist rig.
'There's a lot of wind out there. You won't want much sail. Not while you're learning.'
I intend to try a shunting rig eventually but I tend to pay attention to Graeme. He's lived in his house since 1948 and sailed at the wharf at the end of the road for most of those years. When the sun comes out after a cool night, the onshore winds are - um - exciting. Even in the Optimist they're exciting. You come back to shore and a little old lady walking her dog along the seafront stops and says
'I bet that was a good sail!'
and you hazard a private guess that she was once Graeme's Outdoor Ed mistress.

I hied me along to the builders' merchant with an offcut from the side planks and examined their racks full of plywood until Jasper came out to attend to me.
"Hi Jasper, I'm after some sheets like this."
"Uh, let's have a look - that's 4mm SS UT and it should be in this rack, aaaaand - looks like we haven't got any. It's Woody, not Jasper. I do look like Jasper. Only more handsome."
"Oh, sorry, Woody."
"Woolly. Not Woody."
"Oh, sorry Woolly. - Why d'they call you Woolly?"
"Short for William."
Damn. Willie. I can never quite get the local accent. - One of my neighbours always calls me Ruptured. -

Anyway, as Jasp -  as Wullie pointed out, there was no 4mm SS UT. And none in Nelson, Takaka, or Blenheim, according to their computer. No demand. At $76 dollars a sheet I can imagine the explanation, but it means that I'm either going to have to use 4mm CD UT or order a palletful, which means sixty sheets. SS means both sides have a lovely smooth intact veneer. CD means only one side is smooth and the other side is oh, so-so. UT means untreated, were anyone to ask. I gather it takes glue better. Though how they glue it up into ply becomes an unanswered question.

Accordingly I have the choice of whether to put the so-so side on the outside where at least I can keep an eye on it for delamination, or use 7mm ply instead.  Since every naval architect  tells me that boats always get heavier as you build them, I'm taking a chance on the rubbish grade 4mm, and reinforcing all the edges.

The next task is to glue laths around the bulkheads' edges, and this includes gluing a reinforced hole in the middle. Slightly dodgy 4mm ply isn't going to like inspection hatches, but I don't want a sealed bulkhead full of damp and foetid air where rust and moths break in and steal. - Specifically, rot since the wood is untreated. - So it needs a whacking great big opening that can be removed after each excursion. Mr. Grill had the cunning idea of fitting the top of a bucket as a waterproof hatch.

CRT's buckets are $28 each with a lid but we have lots of old paint buckets wh. are free, and I like the idea of free. Unf. those paint buckets go brittle in the sunshine, so I'll have a problem when the inevitable happens. A bridge to be crossed anon.

In order to make the hole a nice circle I made a compasses extension for the jigsaw, and drilled a central hole as a pivot, and proudly started cutting, and it didn't work. The jigsaw cut a spiral, not a circle. When I watched, the reciprocating saw-blade began to flex at an angle, the angle increasing as the curve proceeded. I took the extension off and cut it much more accurately by hand.

It keeps surprising me that sticking a motor onto a tool is a way of simultaneously making it more saleable and less controllable. I can't think why I should be surprised, since it's a fairly consistent result. We are sold the idea that attaching 400W and a long black cable with an electric plug at the end of it will now obviate the need for skill.