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.

More sewing

In a publication called A Spirit of Enquiry Essays for Ted Wright 1993 there's an essay entitled Sewn Boats of the Indian Ocean; and Plate 20.3 shows a Saamish sewn boat in the village of Notozersk, Russia. As the Indian Ocean is no-where near Russia, we conclude that sewing and navigation are divorced skills.

Certainly sewing and arithmetic are divorced skills: I was so keen to get on with sewing the garboard strakes together that I didn't pay attention to how long the boat was going to be until I noticed that I was going to have to chop seven inches off the blunt end or the side planks wouldn't meet in the middle. Think you're stupid?  - Not as stupid as me.

I put the templates on the upturned Optimist and found that I was short of quite a lot of area. My boat was going to sit quite a bit deeper in the water than I hoped.

Mr. Dierking's solution is to bolt a box in between the ends, extending overall length by quite a bit. Having plenty of offcuts, I thought I'd glue some 7mm thick side-plank extensions on to restore my missing 14 inches.

Out with the router: machine a 2mm deep strip at one end of the extension, offer it up against 4mm side plank, wonder why 2mm is standing proud, realise 7mm minus 2mm does not equal 4mm, wonder where brain was this morning, say usual word, put head momentarily in bucket of water, machine 2 more mm off, now have flat surface when the two are touching.

I mixed up some epoxy and having now read the Epiglass instruction PDF, simply put bricks on top of them because I'd just read that the epoxy sticks better if it's a millimetre thick rather than a squozen-thin layer of glue.

 
They were left for 36 hours partly because it's cold and partly because I had a bicycle fork to replace. And with the broken fork in mind I didn't want any stress concentrations so afterwards I set to work feathering off the over-glued parts, and it's a good job I did because quite a bit of it had no glue underneath. It merely looked glued. This joint is going to be in the middle of the boat, the point of maximum strain. I do not want it to break. I put a flap-wheel in the drill and ground away everything that wasn't glued, firmly resolving to be careful when applying fibreglass tape afterwards.

Next to sewing, and back to the original plan of standing the thing upright, dodging round it like a damsel round a maypole as I tried to poke the monofilament three times through a 2mm hole. That wore a bit thin and I got John to help, and when he wore a bit thin I finally tried a needle and wished I'd done so before because then it was quite easy. The nylon won't go through the eye of the needle any more than a camel will go through a rich man, but I found that tapping the nylon with a hammer flattened the end and then it did go through, and the nylon jammed in the hole and didn't work free so I was much pleased with myself. Four metres of nylon does mean you have to take your shoes off or you're always tangling things up.

I found the only way to keep the stitches tight was to sew it with the side planks open, like a tryptich.

Eventually I had to tackle the curve.

 
And to make the curve easier, I used the copper wire as a temporary fastening, heating it red hot to anneal it because otherwise it's too stiff and breaks on being twisted. The final stitches were 'stremely difficult, and I might have to think a bit more about this for the other end.


Pleasingly, the two curves matched, though there is a transition point. The side plank sits on the outside of the pointy end of the garboard strakes, and actually makes a neat join.

Moreover the sides struggle with my imperfect woodworking fit, and needed some gentle coaxing with a broken kitchen knife to transish at matching points on each side.

But where the sides sit on the top of the middle bit of the boat's garboard strakes, they slide down inside the boat, leaving a sticky-outy-ledge on the outside. I shall carve lots of tiny wedges and hammer them into the lashings inside the boat, and hope and pray that they squeeze the side-planks outwards to make a smooth outside edge.

Finally I sewed the ends of the sideplanks together, and coming to the bottom found a vast cavernous gaping hole which will have to be plugged with teased-out chopped strand mat glass fibre.

It can be the back end of the boat.

I expect it'll be all ugly and lumpy and make all the boat-builders wince inwardly but who cares? The front end can be pristine and glorious and beautiful and sharp and slice through errant jet-skiers like a scalpel, making all the swimmers happy. Swimmers hate the jet-skiers. They always ignore the 200 metre buoys and come ploughing inshore at full speed. Actually everyone hates the jet-skiers, even the jet-skiers themselves. I've often watched them. A huge effort to launch the craft, ten minutes driving pointlessly round in circles too far off-shore to entice the applause of an admiring throng. Then they come back to the beach a bit shame-faced, squirting out two-stroke fumes before switching off the engine and trying to round up parents and grandparents to pull the ghastly vehicle out of the water onto a boat trailer. Bit of luck the eventual oil crisis will deal their death blow.

Duplo fork

The cheery thing about building your own bikes is that when major structural failure happens the only trauma is having to paint it after the repair. I hate painting. Everybody hates painting. It isn't news.

 Quick scan of the collection of old forks for a stout 406 pair; suitable candidate chosen and a thingy welded on for the steerer rod and another thingy for the drum brake arm. I can't be bothered to describe them and I don't suppose anyone could be bothered to read about them.

The steerer tube of this fork was quite short. I had been meaning to cut the head tube of the Duplo bike for ages: the extra length was surplus weight and I've no idea why I left it that long, other, perhaps, than to irritate Mr. English who likes all his bikes to have no extraneous metal whatsoever.

A head tube needs to be an inch-and-a-half shorter than a steerer tube, and not being Mr. Knight who would make an archival quality industrial jig out of tool steel for the purpose on his Myford lathe, I was stuck with how to square it off. Rather more difficult to square the ends of a head tube when it's already welded into the frame: you can't pop it in the three-jaw and do the job in two minutes.
Eventually it occurred to me that I could rotate a rod inside the head tube with an oversize lip fitted with sandpaper.

 In the bling pile I found two candidates. One was a short rusty cylinder. The other was some kind of weird yellow item with a hole and a grub screw to fix something in the hole. No idea what it was. One picks up all sorts of odd things on the roadside and it's always a happy surprise to find a use for them. As the rusty cylinder fitted perfectly I didn't need the grub screw; and to make it fit the head tube I wrapped it in masking tape. For the sake of clarity we will refer to this fantastically sophisticated tool as the Thing.

A Thing, this morning.

 
A scrap of 120 grit abrasive, and onto a block of wood where the hole in the yellow item was used to mark a circle, which was then cut out with a chisel made out of a short length of Number Eight Wire. - No, it really was. Except that I have recently learnt that Number Eight Wire refers to the old sort, a very pure iron, malleable as copper which is how they used to fix everything with it. Today's fencing wire is galvanised high-tensile stuff so you can't fix things with it, though you can make small wood-carving chisels out of it, and even smaller chisels out of bicycle spokes which are also high-carbon steel. File to shape, heat to cherry red, plunge in Nutella jar full of rusty water, and there's your chisel. A handle, if you must, by drilling a hole in a stick of firewood. It never ceases to amaze me how many things you really don't need to buy in a hardware shop. I watched a neighbour the other day wielding a leaf blower. Are we all stupid? You really need a petroleum-powered motorized anti-vacuum cleaner to sweep the path? - You can do the job quicker and more effectively by cutting a couple of twigs of broom - hence the name - and lashing them to a manuka stick with a strip of rubber inner-tube. It'll take you all of ten minutes to make.

The bike's head tube I marked at the cutting point with more masking tape, deployed a hacksaw, and then marked the sawn edge with a felt pen.

Sawn off head tube, marked with felt pen

 

In with the Thing, rotated once, and then I could see where the abrasive paper had rubbed the felt pen marks off. Apply file to the high spots; repeat a great many times, stop for lunch.

Using the Thing to mark the high spots

 
When the bearing cup sat squarely, I assembled everything with the new fork, and went for an uneventful ride. Very slow today. Yesterday had left my legs all wobbly and dead. Tomorrow I have to stop thinking about fragmenting recumbent bicycles and resume the happy contemplation of boat construction.

The Duplo bike, now with its fourth set of front forks, second back wheel, third front wheel, second lot of neck rests, third crank set. But still on its first chain. Because I wax my chains, and they really do last forever.

Broken fork

Boatbuilding, I discover, largely comprises waiting for epoxy to set. In the hot summer sun this is about an hour; in rainy springtime when you can't leave stuff outside, it's twenty-four hours and still a tiny bit tacky.

Accordingly I took the Duplo bike out for a ride, slightly vexed as I got up the road to remember I'd forgotten to oil the rear suspension bushes which have been squeaking for a week. Just at the top of the road there was a strap, and being incurable in the matter of picking up useless bling, I stopped and collected it.

As I set off again, I noticed a yellow jersey on a piece of carbon fibre a good fifty yards behind. Being a puerile git, like all other cyclists, I set to work pedalling briskly. My Mirrycle kept me abreast of his progress, and irritatingly I wasn't dropping him so I had to pedal harder. The gap increased to a hundred yards, two hundred, but the West Bank Road undulates, and the Duplo bike weighs 44lbs and is unco-operative on hills and the gap would close again. The legs were working hard but not as hard as the lungs, struggling to get enough oxygen in. My mouth was dry and I was gasping for breath, but obviously my pursuer, equally puerile, was also pedalling hard and gasping for breath too. The speed said there had to be a slight tailwind, and yet it wasn't fast enough. Honour! - honour was at stake. - One could not permit an upright bicycle to catch a recumbent. - The wretched fellow stayed there, a hundred yards behind, two hundred, then only a hundred again. Would he carry on up the valley as I crossed the bridge? How long could I keep this up? Could he hear my squeaking suspension? It was horrible.

Came the bridge, and over it, and back towards town round the Alexander Bluffs themselves, a steep outcrop that protects the bridge from the wind. - And dammit, there he was, following me back into town.

Now, have you ever prayed for a headwind? Neither had I until now. But a headwind, a headwind - for the laws of physics are immutable. - And yes! There it was, a strong one too, strong enough to knock my speed right down to sixteen miles an hour. Hah! If it did that to me, what would it do to him? - I kept pedalling, hard, and the speed slowly crept back up - 16.5, 17, 18, 18.7, 19.1 - and on past the Kellys, past Atamai, - where was he? - on past the Bisleys, and yes! - oh Mirrycle, my blessings on you - there he wasn't.

He'd vanished.

Nothing behind me at all. The headwind had finally done for him. Honour was saved. (But I thought I'd better not let up because the demoralisation of being caught now would have been too embarrassing.)

With nobody in the mirror I was able to return my focus to the irritating squeaking from the suspension, and the odd thing was that it wasn't coming from under my seat but from the front wheel somewhere. Yet the front wheel is not suspended. It's a rigid fork. It was most puzzling.

There's a cycle path along the state highway, and where it passes the drug dealer's house he - the drug dealer - has unkindly widened his driveway and made a botch of the slope, so if you hit it at speed you get air, as the skiers say. Your front wheel leaps off the ground. I was doing well over twenty miles an hour when I got air, and as the front wheel landed the bike twitched sharply to the side but I managed to catch it with only a slight alarum, and slowing only for the blind corner, because pursuer or no pursuer I didn't want a head-on collision with some innocent kid on his bike, I applied full power to sprint me home, and I actually hit the driveway exactly as the computer registered 53 minutes. The ride is 18.55 miles, so that was an average of 21mph, and I was pretty happy, if pretty knackered.

A pause, then to Saturday's task of mowing the lawn. And, while still sweaty, I thought I'd go back into town and get some raspberry ripple ice cream. - Cos I like raspberry ripple ice cream, that's why, I'm not an ice cream snob - anyway shut up interrupting - and as I got onto the bridge I remembered the irritating squeaking, still coming from the front wheel. And I looked forward and down. And this is what I saw.

Cause? Note the stress concentration below the welded steering pivot, and note also that a fortnight ago I fitted a drum brake which acts on the left arm of the fork. Six thousand miles and no chain wear, but twice now the frame's snapped. - The beauty of steel, as we fans of it like to say. You get plenty of warning before a catastrophe.

This was a thin-walled, light-weight, cheap child's BMX fork. Tomorrow 'twill be bicycle repair time, not boatbuilding.

Sewing

Holes drilled: now to the sewing.  Easy, methought*.  Wrong. 

First I was going to use monofilament nylon, and then I remembered that I cannot tie it in a million years.  Copper wire, then.  And because I am a miserly hoarder who can't bear to throw rubbish away I delved under the bench for a cardboard box and found therein all the bits of wire that the electrician had left when we did the kitchen. There is a very fortunate thing about electricians, though all the tradesmen complain about it: they never sweep their mess up. When an electrician has visited, you will always find eighty-one short pieces of red, brown and green/yellow plastic coated pieces of copper wire. And what I have now discovered is that provided they're minimum of 63mm in length, they will sew a wooden board to another wooden board.

First there was the obligatory Human Sacrifice. In the olden days when the natives were more tractable you'd get an Aztec and in a hideous illustration found only in National Geographic you'd do away with him in a welter of blood and screams.  Today it is necessary only to let me loose in the workshop. I started to strip the short bits of wire, and one such, the end folded round on itself to facilitate clamping in some unknown appliance, ploughed heartily and without mercy straight through the pulpy end of my left index finger.
"Aaaaah!" I cried.
And then I thought for a half-pico-second, "I am about to regret that."
And then I uttered the usual word.
And then I mopped things up and wandered inside for a plaster.

When you come to sew two flimsy boards together you face the dilemma of how to hold them. This hadn't crossed my stupid mind beforehand: I  simply thought "Sew!" but actually wood isn't as pliable as any of the other things you might be called on to sew and you can't get your hand and eyeball underneath a board that's lying on the floor.  Eventually I realised that since the two garboard strakes would be as a Vee with one another, they would stand upright on the floor at the back. I propped them both up vertically for the first stitch, and so it proved.

After five stitches I thought "I wonder if the middle bit of the bottom ought to be flatter."  And I started to wonder how flat the bottom ought to be if the finished thing was to turn in the water when I want it to tack.  And then I thought "Actually, I don't know what I'm doing here", so I popped next door and dragged Graeme over, and he told me that Wharram sews the sides together flat, and then forces them apart and they make their own rocker. "Get on with it" he said, not for the first time, "and then you'll see what will work."

When he'd gone I thought  "I wonder how long it will be until I gouge myself on one of these exposed sharp copper wire ends."  So I crept up into the loft and got a roll of 35lbs breaking strain nylon monofilament and found that it is, actually,  possible to tie a timber hitch and jam it in one of the holes - they're 2mm in diameter - and then to sew three times through it creating two loops, which is a holding-together-strength of 70 lbs.

However. When you come to open the two boards apart, you find they don't want to pivot on one another's corner. One instantly slips down onto t'other. So this was going to be a problem. And then I thought that since the nylon sewing was going rather well I'd remove the copper stitches before they stabbed me again, a rare moment's prudency. Running short of fishing line I had to nip to the Warehouse, the Warehouse, where everything's open and broken, because all the other shops were shut. (Otherwise I never go there, on principle.)  I discovered that they didn't have any 35lbs fishing line, and true to form when I got their 40lbs home I found it was thinner and weaker than the 35lbs I'd got from Walkers of Trowell 27 years ago. Trowell is where sometimes NFI was to be found written in a patient's notes, standing for Normal For Ilkeston. (They had several of these acronyms. FLK meant Funny Looking Kid, so some startled young paediatrician didn't go off doing hundreds of unnecessary invasive tests.)

Nevertheless the 40lbs monofilament held, and even allowed me to open the whole thing apart, when I discovered that I was, after all, going to need some formers to hold the two planks at the correct angle to one another, or the end wouldn't bend upwards at the curve to match my carefully prepared side planks. So I made three formers to see what happened, with angles 22, 44 and 55 degrees off a straight line. (Okay, Mr. Knight you horrid mathematician, with angles of 158, 136 and 125 degrees.)

Happily, by experimenting, I found that I could vary the amount of rocker by moving the 44 degree former backward or forward, and I don't seem to need the 55 degree former at all.

I was surprised at how much force was needed to prise the planks apart, and got John to help with his bulk and muscle. He was not in a bulk and muscle mood, however: he was in a composing poetry mood. John has a healthy teenage disdain for poetry, and his verse tends toward the irreverent, invariably being brief and also invariably involving words like Knob which have easily thought-of on-the-spot homophones.
"Just lean hard on this, Sir Andrew."
"Who?"
"Andrew Motion. I mistook you for the poet laureate."
"That's a job?"
He was surprised to learn that the job of the poet laureate is, actually, to composed odes and whatnot for state occasions. He immediately had a thought.
"Could I write and ask him to find words that rhyme?"
"You probably could, though I don't know that he'd reply."
"I'll say I'm composing a poem for the Queen's jubilee, and ask him what rhymes with Regina."

Afterwards it occurred to me that I have a car scissor-jack doing nothing, so I screwed it to the rafters to save more poetic ramblings when forcing the planks apart with the permanent formers.

Anyway, all the people who've ever made these things before were right, of course. The nylon will hold everything together, even the very sharply bent tip, provided you sew it very tightly when the boards are flat together like a close book.

And the boards pivoting on their sharp edges didn't turn out to be a problem - all I did was lightly tap them into place with a dowel and a hammer, and the tension of the nylon keeps them there.

Now the epoxy is hardening, with the addition of a 60 watt light bulb as a heater and lots of rags and bits of cardboard to keep the heat in and quite a few checks to be sure it isn't kept in enough to catch fire.


*Methought.  Hapax legomenon - until now - courtesy of Miss Davena Watkin.