Time for another episode I think!
‘Natterer’ – A shipbuilding Odyssey? – Part 5
The final two planks, one on each side, had to exactly fill the remaining gap and had to be very accurately measured and profiled on both edges. Each plank took two nights to shape and fix in place, and I hadn’t any margin for error, as I was down to my last good pieces of timber. ‘Measure twice, cut once’ was the order of the day, and happily at the end of it the fit was good.
I left the hull for three days to fully dry, before attempting to invert it, and then took my courage in my hands, unscrewed all the shadows from the building board, and for the first time turned the hull upright. What a wonderful sight! The hull had looked just like an interesting curved surface when upside down, but when upright it immediately became alive, and the true beauty of the hull form could be seen, with the subtle rise of the sheer to bow and stern, and the way the turn of the bilge gradually turned in to the tuck of her stern under the counter – stop it, Ted – you’re a married man!
Now for the next stage, the fitting of the internal ribs. The hull had a total of 16 bent ribs down it’s length, with a further nine heavier carved frames. The ribs were continuous from gunwhale to gunwhale, except where the hull narrowed at each end, and the keelson had then to be fitted before the frames were installed. The ribs were 7 x 3mm mahogany, and were pre-bent around a piece of steel tube, heated by a gas torch. This operation proved tricky, as the difference between too little force in bending and consequent total ineffectiveness, and too much with consequent breakage was very small. I broke many pieces before I got the hang of it, and burnt my fingers several times, but eventually managed a full set.
Tap, tap tap – ‘One thousand three hundred and seven’; Tap, tap tap – ‘One thousand three hundred and eight’; Tap, tap, tap – ‘One thousand three hundred……….’ ; - You’ve guessed it; we’re at the riveting stage.
Full size construction uses copper nails which are driven through the timbers. A copper “rove” or washer is then driven down over the nail, excess nail nipped off, and the end then hammered over or ‘upset’ to ‘clench’ the nail. In full size it is a two man job, one to drive and hold the nail, and the other on the inside of the boat roving, nipping and clenching.
I used 1/16 x ½ inch copper rivets, which were pretty well to scale, but had great difficulty finding something to use as roves. Many modellers use modern 1/16” i.d. brass washers, but these tend to end up grossly overscale, and to my mind totally spoil the effect. I couldn’t find 1/16 washers in copper, and reluctantly decided I would have to use brass, but wasn’t happy about the scale effect. As luck would have it, I called in on my usual nut and bolt company when out and about, and asked if they had any small 1/16” i.d. washers. ‘Oh yes, the computer says we’ve got a packet in stock with about 1100 in’. When they eventually found them, at the back of the biggest warehouse you’ve ever seen, I was ecstatic - the washers were like nothing I’d ever seen before, and had a very small o.d. - they were exact scale! The only problem was I needed at least 1600. The company said they would get some more from the same supplier, but when they came, they were much wider. We checked, and found the original washers were stocked in 1981, to an obsolete standard, and no longer available!
This was a poser, but I decided I would use the original washers where they showed on the finished boat, and the wider ones where hidden. So first I counted the original washers to make sure I had enough for this course of action and found I had well over 2500! These things were tiny, and all of them could have fitted in a large egg-cup - the original supplier must have said ‘sod it, I’m not counting those’ and just chucked a handful in the bag to fill the warehouse’s order.
With the immediate problem solved, I started to fit the ribs. One of the midships shadows was removed, and the rib glued in place. Next, 1/16” holes were drilled through plank and rib, and the outside countered-bored to a depth of approx. 1/16” to allow the head of the rivet to sink in so it wouldn’t disappear when sanded flush. The rivet was then driven into the hole after being dipped in Araldite, before a washer was threaded over the shank on the inside, the rivet nipped off about 3/32” above the washer, and the end turned over, or ‘upset’ (Lovely word) to clench it home, using a light hammer and a heavy lump of steel as an anvil against the rivet head. I didn’t of course do each operation on each rivet one at a time, but drilled all the holes in one go, then countered-bored and so on. I found the work to be quite physically demanding, and found I could only put in a maximum of about 120 rivets in a three hour session.
I started off very tentatively, only removing one shadow at a time, and being very careful with the hammering, fully expecting all the planking joints to open, but soon found there wasn’t a problem and ended up with no shadows in place at all, as they just got in the way! The hull remained absolutely stable throughout.
1600 rivets later, all the ribs were in place, and I turned my attention to the frames.
(Sorry about the quality of the photos - still on copies of old photos!)
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Topic: Natterer - A shipbuilding Odyssey? (Read 24975 times)