Chesapeake 17LT progress #1

Scarfing the hull bottom and side panel blanks was a piece of cake, my first (nervous) attempt!   After cutting-out the panels from the blanks, I tested one of the scarfs by putting a piece of the offcut vertically into my vice (vise?) and pushing down on the unsecured end - took quite some force before the ply splintered and broke, leaving the joint untouched.   Impressive!

Reached the stage of preparing to glue the sheers to the hull sides.   This calls for the sheer to sit ¼” higher than the top of the to-be-glued-on side panels so that it (the sheer) can be planed to the correct angle along the hull side to accept a good fit with the deck later.   Getting this ¼” accurate was going to be tricky – slippery epoxy and all that!   So I scribed a line along each sheer on the surface that was to be glued, ¼” down from its top: then lightly drove in some 1” brads along this line, at about 8”centres.   These brads will create little ‘stops’ so that by pressing the sheer gently down against them after applying the epoxy, it will not shift while I’m securing the clamps, and the required ¼” will be easily and quite accurately achieved.   The deck camber is greatest in the centre of the craft (where the full ¼” will be needed), but the camber gradually reduces so that the decks are nearly flat at the stem and stern.   So, I only made the centre 1/3rd or so of the sheer sit up by the ¼” – working towards the stem and stern I allowed the top of the sheer to curve down gently so as to almost come level with the top of the hull side at the extreme ends – less planing!

 At this point I’ll be ready for the next step, stitching the hull.   It seemed worthwhile to consider a suggestion of using very thin nylon cable ties instead of copper wire – quicker, possibly easier.   But I mentally pictured the subsequent filleting process. Since these ties cannot be pressed flat against the hull panels, unlike copper wire, it seemed likely that the ties would ‘bridge’ the adjoining ply hull panels from hole to hole, especially with sharp angled sections such as at the stem and stern.   This would create little steps every 4” or so along the filleting line that would markedly slow down the filleting process – or so I reason, and I don’t want to use the time-consuming tabbing process to overcome this.   So it’s back to copper wire, meaning that I can run the fillets the whole length of the hull section I’m working on all in one go.  Lol from Oz - Jan 7th 2009

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RE: Chesapeake 17LT progress #1

Lol, never tried cable ties but CLC has this to say about them:

The larger size hole is enough to put me off. I'd think it would be more difficult re-adjust the fit than with copper wire too. At any rate, the copper wire seemed very easy to work with to me.

Regarding tabs, I built a CH17LT in class leaving the wires in. Class is time-constrained so there really isn't any option to do otherwise there.

Shearwater 16 I tabbed. I found this quite easy and I don't think much more time-consuming. Except for that you have to wait an extra day for the tabs to cure. But that isn't time spent working and so it didn't bother me. Leaving the wires in makes the filleting marginally more difficult and will result in thicker fillets. You have to be careful to make sure that the wires are clipped closely and sanded carefully on the outside of the hull, and even though I felt I was pretty careful  about that, there were still a few problem wires that wanted make a funny bubble or poke into the glass from underneath. I think the time spent carefully treating the wire remnants on the outside of the hull can make up for a good bit of any time spent pulling the wires out (pretty fast) and filling the little holes (takes some time, not that bad) left behind.

At any rate, unless I was trying to get a hull together in a big hurry, I would tab the joints. I didn't think it was bad at all.

If there is one thing about my Shearwater I would have do differently at that point, it is mainly to have taken even more time than I did sighting down all the joints and -re-adjusting wires. Even though I thought I was pretty careful at the time, I ended up with a slight mis-alignment in the side-panels at the bow. I was pretty much able to take it out in the fairing process and the boat seems to track straight as an arrow so I seem to have gotten away with it but if I do it again, I'll be even more careful. I didn't have a laser level when I did that. Got one later and that probably would have been really helpful to have during the wiring/alignment process.


Ogata (eric)

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