Today we started to tackle the inside bulkheads. There are two on this vessel, one fore, one mid ships, made from supplied plywood. The basic shapes are already CNC routed out of the overall plywood sheet. However, they must be fitted to the particular hull shape. Since these hulls are GRP the inside surface finish is variable so a little bit of work to make them fit the hull better will pay off in a better looking job. To locate the bulkhead locations refer to the instruction sheet. The sheet gives the locations measure from the tip of the bow. How to get this measurement accurately to the hull? Using a square set upright inside the hull on the keel line, bring a measuring stick from the point of the bow to the square. Adjust the square until the desire 135 MM distance (as per the drawings, is achieved. Mark the hull at the keel center line and square intersection point. Now extend this line up to the top of the hull in a square fashion. If you have done it accurately, the bulkhead should sit square and vertical in the hull. The amidships bulkhead merely uses the forward bulkhead line as a reference point for measurement. When you are satisfied with the location, its time to fit the bulkhead to the hull. Set a light low into the hull on the opposite side to which you are viewing the bulkhead. This will show light through the gaps that don’t meet the hull properly. Sand, trim and tweak the bulkhead until the light gaps are as small as possible, or non existent. The bulkheads should slip into place easily and not push out or distort the hull. I wanted the centers of my bulkheads open for wiring, ballast access, and battery access if necessary. I decided to leave 5/8” material around the outside of the bulkhead. Now special reason for that number except it appeared to be right and should be plenty strong enough. I then used my jigsaw to cut out the center of the bulkheads. The burrs were sanded and cleaned up and the bulkheads are test fitted. All well I offered up the Decaperm motor I plan to use for the vessel. In the photo with the decaperm you will notice a pencil line across the keel of the hull. This is the position the prop shaft comes into the hull. I may well be shortening the prop tub and shaft to allow more room for a proper universal joint.
All looking well, I did a test fit of the sub deck. Here again a little sanding and tweaking was done to get the deck to fit comfortably. Now is time to epoxy the bulkheads into place. John