CRAFTSMANSHIP Boatbuilder’s Notes EXPERT ADVICE
Bulkhead building
BY WILL STIRLING
There are different ways to make a bulkhead. The detail and layout of this one is accurate for a boat of c1880, fitting for our 19th-century cutter yacht in build. It represents a lot of effort and expense given that it is ‘just a bulkhead’. However, it may be around for a hundred years so represents a small investment. Make a template of the bulkhead in hardboard and draw out the panels as they will be. The bulkhead layout will define the interior, so plan the height and width of seats and berths, the depth of cupboards and the door widths. Choose air-dried, well-seasoned
timber. Make up the frame first. These stiles and ledges are 4in (10cm) wide and 1in (2.5cm) thick. To give compression posts throughout the boat, the central stiles are 2in thick. Do not make the mortises and tenons too tight: a push fit is right. When you assemble the frame, the increment of small discrepancies and twists will mean that the frame needs to be tapped and sash- cramped together. If the mortises and tenons start as a hammer-driven fit you will probably damage the frame in assembly, particularly if you get a glue panic on.
Machine all the grooves for the panels when the frame is in pieces.
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Dry assemble the frame on top of the pattern and measure for the panels, remembering to add the depth of the groove in the frame on each side of the visible panel.
LOOSE TONGUES
Machine up timber for the panels and glue together with loose tongues. Have an eye on matching similar grain in the parts that make up the panels and between the panels themselves. In these bulkheads the
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5 90 CLASSIC BOAT MARCH 2012
Building the frame
Fielding a panel
Waxing the panel edges
Dry fitting the fielded panels the end
Gluing up the bulkhead – best done outside the boat, provided it will fit down the hatch
top panels are flat. These are thinner at 5/8in (15mm). The lower panels are fielded. These begin at the same thickness as the frame. The rough fielding is done on the table saw with the blade set at an angle. These are then made neat with a very sharp plane and the edges made to fit into the frame grooves.
Dry fit the whole bulkhead together on the floor. If you can fit it down the hatch, glue up outside the boat. Wax all of the panel edges with a candle. This will stop the glue adhering and allow the panel to adjust to atmospheric moisture content without splitting. Have everything to hand and put some glue on each tenon. The tenons can be dowelled if required. These bulkeads have a
contemporary beading trim around each panel. It overlaps the frame and is fastened to the frame and not the panel. This gives the bulkhead a 3D effect; almost early magic eye.
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