Today I managed to get 4 bulkheads stood and braced, all square, plumb, level and at the correct distance apart. I know this because I checked, double checked and triple checked. These are the four lighter 19mm bulkheads but tomorrow I will find the going a bit harder on the heavier ones especially the mdf temps.
The procedure for each bulkhead is pretty much the same. Because I have made the legs the same height it is fairly simple to set them on the bulkheads in pretty much the correct position. I clamp the bulkhead in place and secure it with screws once everything lines up correctly. This way I can make any adjustments on the strongback if the legs are out at all. The same goes for the legs on the strongback, when I initially stand each bulkhead I clamp the legs in the correct position until I have everything correct and I then screw the legs to the strongback and release the clamps. The final stage on each is to brace each leg.
There are 4 axis that need to be correct, all are equally important. First the bulkhead needs to be at the correct height. I have all of the DWL lines at 2000mm above the top of the strongback. Then after bulkhead 0 which has no point of reference, each bulkhead has a set distance from the face of bulkhead 0. Then the bulkhead needs to be level along the waterline and the centreline (up and down as well as left to right) and finally the bulkhead cannot have any twist in it, so that it is the same measurement from bulkhead 0 at all places. If all of these are correct then the face of the bulkhead should also be square to the stringline that I have set at WL1200.
As well as the stringlines I have at centreline stringline above, I have a centreline on the strongback, a stringline either side at DWL (2000 above the level of strongback) and a stringline to the side at WL1200 but used to square the panels to. I will also run stringlines at WL1200 either side as one final check that all is well.
The theodolite turned out to be not so useful because it is so bright that you cant see the laser mark. We have a beeping thing that detects it and tells you via an LCD if you need to go lower or higher but we also have 2 other laser levels so we ran one down the centreline at WL1200 and made sure it hit each panel at the intersection of the 2 lines.
These images are placed in order of sequence to show the bulkheads stood so far.