W22 Building Header Building the W22 Trimaran

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May 25, 2014

W22 Build INDEX

Building the W22—Article #8

Completing the sides and gunwale extension

Happily, our builder is finally back from his home construction project, and is once again enjoying to make progress on his W22. At the close of the last article, the sides were being trial fitted in order to correctly match and cut the panel joints. These joints were then bonded, with a layer of cloth tape recessed into the foam surfaces.

In Photo-1, we can now see the upper side panel temporarily screwed into the knuckle flange, until the epoxy used to bed it in place, has cured. The screws are then removed. Photo-2 shows the cloth tape over the butt join in the foam core material and Photo-3 shows several thickness of foam strips that can make up the core of the stem. This foam will then be rounded off and faired to the hull sides, prior to sheathing.


Photo-4 shows flush hatch openings within the cabin sole, being prepared with a backup ring of foam to give support for the cover itself. All will then be glassed before fitting in the hull. Photo-5 shows temporary supports across the hull to hold the top of the side panels until the under-gunwale panels are fitted. Photo-6 shows the first under-gunwale foam panel fitted in place. If the selected foam is thick as in this example, the foam does not need to be pre-sheathed with glass - but if it is 10mm or less, then it’s advisable to pre-sheath the inside with at least one layer of biax cloth before fitting.


Photo-7 shows an under-gunwale panel being measured – based on panel dimensions given on the plans. Photo 8, shows the under-gunwale panels all in place and Photo-9 shows the same from a forward perspective – and also showing temporary plywood forms that will be used to support the core strips used to mould the cuddy top … either using cedar or foam strips. This helps to visualize how the cuddy will integrate with the hull.


Photo-10 shows the same from the port bow and Photo-11 shows the transom, with one possible way of mounting an outboard motor support, permitting the shaft to pass through a Vee in the hull bottom that extends aft of the transom. Finally, Photo 12 shows the main hull from the stern, with a tape of CF laid over the hull foam in way of the waterstays, to add extra compression resistance to the sides at this point.


Article 9 will show how the main hull is sheathed, after the foam joints are filleted and faired.

See W22 Build INDEX for earlier articles.

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