Builders' Forum Archives
Re: Checking for twist
Posted by CLC on Jul 31, 2005
>>>>>>I cut the bulkheads out according to the plans, but they are not even close to fitting.
You get some variation due to sheerclamp density and so on, but that's a LOT of delta. Years ago I built a West River from plans (no CNC-cut parts or patterns) and I was struck by how much the hull shape changed in the multichine boats when the hull panels differed even a tiny amount from the computer-derived offsets. Cutting outside the pencil lines for each panel edge, for example, added up to large errors once the hull was wired together. The multichine boats aren't especially forgiving that way.
A few fractions of an inch here or there won't matter, but whole inches do matter. I wouldn't unstitch the whole boat, but I WOULD endeavor to bring the cross-section shapes close to the shapes shown in the plans, to preserve important performance perameters. IE, the "facets" of the hull at each bulkhead location should be at least parallel to the designed bulkhead, even if you have to cut a larger bulkhead.
In Response to: Checking for twist by Andrew King on Jul 31, 2005