Plank One is on

Another wet Saturday was put to good use, when the first plank sections went on and three of us got a nice masterclass from Richard Pierce, now returned from his adventures in the States.

Our (well, mainly my) efforts at bevelling the keelson and stems to meet the planks were reviewed and mistakes corrected. I had been over-enthusiastic in the sections between the moulds, producing a slight scalloping. It’s quite easy to do this, as one tends to lift the plane when getting near to the moulds and naturally press harder between them. This can’t happen again on Seil Skiff Number One, as there’s only one keelson per hull, but it’s a warning for when we get to our second ship. Fortunately I hadn’t done anything that couldn’t be smoothed out and Richard soon had things sorted.

At the stems I had gone the other way, being afraid of removing too much material. Richard explained how the planks will naturally take a concave curve at the ends, clearly visible in the picture of the finished job. The natural tendency when planing is to concentrate on the sides of the work piece, so that one produces a convex profile and accordingly a bad joint or, worse, an outward lengthwise bow that will produce a bulge in the plank once it’s on, with a compensating flat in the section behind, as the material for the bulge has to be borrowed from somewhere. While one is always anxious not to remove too much it’s actually a lesser sin than not taking enough off. Wood can’t be compressed, whereas an accidental void can always be filled with thickened epoxy. This may be a reason why traditionally-trained craftsmen don’t always look kindly on garage boat-builders – they spend years being trained to produce a perfect fit, then we come along, mix our chemical mud-pies and end up with a stronger boat.

Richard quickly supplied the required concavity with a few passes of one of his favourite tools, the angle-grinder, minus safety guard but with sandpaper on a soft rubber disk replacing the usual wheel. The same tool also cleaned up the edges of the moulds and sorted the angles on the frames.

These corrections done we found that both sections lay sweetly in place, requiring only light hand pressure to come in to the stems, with edges completely fair. It was then a simple matter to glue up the faces and hang both port and starboard sections, securing them with a mixture of temporary screws and clamps. The remaining planks will be progressively easier, the sections having to cope with less and less twist as we move towards the sheer.

angle grinder in use

first plank trial fit

first plank in place
second plank clamped on, photo by RP

4 thoughts on “Plank One is on

  • September 18, 2012 at 8:03 am

    Good progress so far! Note we had to trim 1/8″+ from the inboard edges of the garboards to enable them to fit within the notches on the moulds and the centreline of the keel… confirming an error in the kit plank shape rather than the builders! Also there will be excess width where the keel will bed at station 6 when the flat is planed on the garboards…. this could not be corrected without adjusting mould 6, which we elected not to do. The neatly scarfed and glued planks have otherwise laid down with commendable fairness.

    • September 18, 2012 at 8:09 am

      Thanks for comment Richard. To clarify, the minor discrepancy at Station 6 on Iain’s drawing coincides with Mould 10 on the building frame, i.e. the one next to the aft stem.

  • September 18, 2012 at 8:16 am

    Special thanks to George Houston for taking on the plank splicing….. 36 pieces of wood, each of slightly different shape, to be accurately cut with feather edge, carefully aligned and glued together…. This job calls for great care and a methodical approach which thankfully George has!

  • September 18, 2012 at 12:41 pm

    For anyone interested, the grinder is a 115mm mini grinder, fitted with a rubber backing pad and a 36 grit fibre-backed disc, not sandpaper! There are a few essential safety features to observe when using this almost indispensable boatbuilting tool.

    1 Do not remove the guard till you have plenty of experience with the tool.

    2 Always, always keep both hands on or available to grip the grinder… the workpiece should always be held firmly by vice, or something firmly fixed, like the rest of the boat.

    3 Never never hold the part to be ground in one hand, the grinder in the other hand.
    4 Make sure nobody can pull the cable while you are using the tool. a gentle unexpected pull will jerk it from your hand.

    5 Think about dust control.

    I once watched someone racing about the inside of a hull being chased by his grinder. Think about it!

    The mini grinder is the most useful modern boatbuilding tool, but also very dangerous. The bits it takes off are too small and numerous to stick back on again. Used properly, its like stroking the bit of wood you want to remove;. as with any tool, go with the grain.

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