The 3 structural beams are attached to bulkheads 2, 3 and 7. They are fixed with epoxy and stainless steel screws.
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The bulkheads are now attached to the strongbacks using temporary legs. At hull turn over the legs will be removed. The bulkheads are set level and square using a laser level. Once the bulkheads are in place you get a real feel for the shape and size of the boat. I may have made the strongbacks a bit high but I'm not going to change them at this stage. I am going to need a rasied platform to reach the top of the hulls whatever the height of the strongbacks so it probably doesn't make much difference. The hulls are being built as a single piece upside down on a building frame called a strong back. Once complete the hull is turned over and the topside build and fit out can be completed.
The shed isn't big enough to turn the hull so I have to plan to take the hull out of the shed, turn it over and bring it back in to complete the boat. The end wall of the shed is not structural and the plan is to remove the wall, wheel out the hull, flip it over and then wheel it back in. Thus the strongbacks are built on castors and mounted on a runway to allow the hull to be wheeled out. The strong backs are laid out such that each cross piece is at the correct position to support one of the bulkheads. There are 5 structural crossbeams in total but at this stage I need only 3 across bulkheads 2,3 and 7. The other two are to support the fore and aft platforms and will be added later.
The beams are fabricated from ply and timber. The longest is 6 metres so the timber is scarfed together to make make the necessary lengths. The timber is all glued and screwed with epoxy and stainless steel screws. The insides of the beams are all coated in epoxy to prevent water ingress. The outsides will be done later. Once laminated the beams are very strong. The boat hulls are made up up of 9 lateral bulkheads made from marine ply and timber. These are joined lengthwise by timbers to make a frame. Later this frame will be covered in marine ply and then sheathed in fibre glass.
The first job is to make the bulkheads. Some are bulkheads are for only one hull and so two are needed while others cover the full width of the boat. The bulkheads are lofted from the plans and then framed out with timber which is fixed with epoxy and stainless steel screws. The bulkheads are then notched out to take the longitudinal stringers. You need a lot of space to make the bigger frames. I used 18mm ply sheets on trestles as to make 4 large tables. Using trestles allows you to move them into different configurations as needed. The blue polythene is to stop the bulkheads sicking to the table tops. Epoxy won't stick to polythene. |
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