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28 March, '06
Thump thump, grin! Solid, the second layer makes a huge difference to the
feel of the boat, STRONG!!!! |
Planking continues, progress progresses, the levels in the epoxy container and wood pile go down, and the box of stainless steel screws gets lighter.
With one layer of the hull skin on the boat felt good, the hull stiff and solid, the shape showing a full but slippery hull and everything looking very nice.
But with the next layer partly completed along the port side that area feels remarkably different. Thumping it with a fist feels like hitting a solid log, boy that’s strong!
The skin of the boat is two layers of 8.5mm Fijjian Kauri, moulded at different angles across the stringers most of which are laminated from 3 pieces of 20 x 25mm ( total about 2 ½ in x 1in ) and intermediates of 25 x 45 mm ( 1in x 1 ¾ in ) , the biggest gap between stringers is less than a handspan, remember that the builder of this boat is heading into the Southern Ocean , and the first leg of his journey takes him further from land than anywhere else on the planet, and into waters which have weather potentially worse than anywhere else so she’s STRONG.
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Applying glue in a controlled film thickness to large areas of wood requires more than just buttering it on, and the notched trowel leaves ridges of set size at set spacings which when squashed out in between two layers of wood give a known and controlled thickness of glue film.
In this case we have allowed enough to fill the gaps between the planks and any irregularities.
The flat spreader is used to apply a thin layer to the "other" surface so there is full glue coverage to seal the wood.
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Fitting the second layer is easy enough. First the surface of the first layer is smoothed off with a plane so the next layer will sit flat in full contact. Then comes shaping and dry fitting each piece, numbering them then taking them off, glue being squeegeed onto one surface and a notched trowel used to apply a controlled layer of glue to the next piece and the plank screwed on.
We took a day off to go to the big classic boat regatta at Mahurangi, camped in my tent at teh Auckland Regional Council campground at O'Sullivans Bay on the other side from the regatta headquarters. Heres the view from the tent door of Charlie looking out over the estuary mouth, no doubt smelling the salt air and thinking of the voyage to come. |
Any edges that sit up, or areas that do not sit down hard on the underneath layer are pulled into place with pan head screws with big washers under the heads, note that the pilot holes in the outer layer are large enough to be a slip fit on the screw and the pilot holes in the inner layer much smaller so the screw thread engages. If this is not done the screw may not pull the two layers together. Note that the holes left when these screws are pulled out will be filled with epoxy glue before the fibreglass skin is applied and to date the only areas where this has been required is around the tumblehome on the stern topsides, and in the hollow just back from the forefoot. The rest have fitted in with just the permanent screws.
We’re off down to Barts Laminated Timbers again tomorrow, we need to slice some more wood up for the planking. Thanks Malcom, that big bandsaw is a blessing.
JohnWelsford
Designer
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