On The Level
Sleeping on a problem definitely works! After a trip to the local DIY store for a decent spirit level and some plastic cabinet fixings I was ready to start again. Firstly I spent some time making sure that the building floor wasn’t moving around any as yesterday I noticed the levels changing as I moved around! Once that was sorted I took away all the blocks I’d fixed yesterday and started afresh. This is an absolutely critical stage of the build. If the bulkheads and stringers were to be glued in he wrong position the hulls would be twisted, banana shaped and worse. It is essential to get everything levelled and squared perfectly before fixing anything. You will remember that the bulkheads and their temporary legs are made up on a floor drawing so that the legs are exactly the right length if sitting on a perfectly flat floor. Unfortunately, as my floor is not flat I have to use timber shims beneath the legs to get them level. Timber stops are also screwed down on the bulkhead lines to which the legs butt tightly. You can see in the photo below how I’ve used the plastic cabinet fixings to keep everything in position. It is also essential that the backbone is aligned perfectly straight and that the bulkheads are centralised on this line. Wharram recommends that a line is strung between the stem and stern and that timber battens are fixed temporarily to the centre marks of the bulkheads projecting downwards so that they can be aligned to the string. I used some small aluminium angle instead as it was stiffer and easier, and I made final adjustments using a laser. I was really pleased with the result (see the photo) and now have a perfectly aligned skeleton ready to start fixing bulkheads and stringers.
I do appear to have one slight problem however, now that everything is lined up I can see that the keel has a slight curve in it. This must be due to making it up on my uneven floor, The keel is out by 6mm at its worst point. This error seems to be restricted to the first backbone I made and I will have to correct it at some point. I may try pulling out by screwing to a stiff batten or leave it until I fit the metal keel shoes I have in mind and then fair it out.