I double/triple checked my frame and side measurements - all were accurate within a couple of millimetres and the sides were an exact mirror, so this wasn't my problem.Steve_MA wrote:Mike, Sounds like your knee deep into it. I was puzzled too about what portions of the design, frame, bottom, etc have the primary impact on how square it is. One that seems obvious is that if the sides arent exactly the same, it will never be square. I think this is why they have you cut one side based on the other.
I've done a lot of thinking about this overnight! I am pretty sure that this was the reason for the error. My son and I had a little difficulty lining up the sides with the edges of the panel bottom after it was cut out. The plywood I used is exterior and although it is of good quality with no voids, it is designed for building construction and is exactly 1200mm wide (not 1220 as specified in the BoM). This meant a small gap occured on each side at the butt block area - not a problem in itself, because it will fill with epoxy, but it gave extra room for some movement of the sheet when positioning. In addition, we could not quite align the panel with the sides at both transom and bow ends simultaneously - if one end was exactly positioned, the other would be out by about 5mm. I didn't worry about this at the time as the slightly overhanging edge can be trimmed later after filleting, but I now realise that when I pulled the stitches up too tight, I must have forced the hull sides to follow the slightly assymetric bottom panel.I dont know how much the bottom has to do with it because the bottom floats underneath the sides. Now, *if* the bottom is not true and you tighten up the sides to it, thats a problem, agreed.
However, I'm fairly confident now that I can restitch the bottom(loosely! ) and correct the out of square error.
It's 6:45a.m. Saturday here, and I'm just about to go out and get this job done, so I can still do some fillets today. We're in for another hot one today - 32degreesC, although not as bad as yesterday, which got to 38C.
Gotta go build me a boat!