I'm building the WD12 hybrid from plans, I ran into the same thing. Not only did I have to chamfer the sides of the forms, some of them I cut an equal amount (1/8" or so) off each side to keep a fair curve on the hull. No harm in doing that. Even with that there was a slight bit of spring back in the cockpit area when I took the forms back out. When I glue the deck on I'll put a temporary spreader in to align the deck.

George K

Thanks George.

I'm going to pull most of the forms and attempt to get a better fit.  I will likely have to trim #10 to get it to fit properly.  The others can probably be sanded to fit.

Anyone buidling the kit having an issue?

   I suppose anything can happen, but CNC parts are typically very precise and the manuals also tend to be accurate. If I were you, I'd call CLC and get some professional advice. I've heard, though, that molding the Wood Duck's lovely curves can be a bit of a wrestling match.

Birch2

The hull went together just fine.  The bow and stern are a little bit of a challenge, but everything lined up and fit together nicely.  I do not believe there has been any error in assembly.  I agree CNC routing is very precise but there will be variability in the hull.  It is unavoidable.  I just wasn't expecting  to have to modify the forms because like you said they are CNC cut.  I think trimming/sanding them to fit is the prefered solution.  Forcing the forms in will cause problems with deck assembly later in the build.  I believe it will work better to let the hull take the shape it wants to instead of having to spread it out again at assembly. 

just a note that it is fairly common that the hull will need to be spread (pushed out) to acheive its design shape. 

that said, if you are pushing so aggresively that something is going to break or the hull is no longer fair.....then something needs to be adjusted.  also a little variation in hull width (for example an 1/8 of an inch per side) from the drawings can be accomodated without any problems.

but i would not agree that forcing the forms in to acheive the design shape (vs letting the hull take its natural shape) is a problem or causes undue difficulty when you need to attach the hull to the deck.   it is very common that a temporary spreader will be needed and strapping tape will be used to pull the deck and hull into alignment before glueing them together.  even when built together on the same forms, both the hull and deck almost always relax to a shape that varies from the forms and will need to be pulled together with a bit of muscle to get the deck and hull together.

h

   You have two permanent bulkheads that are probably defining the shape of the hull. If forcing the forms distorts the hull shape from a fair curve you should shape them to fit or trim if necessary. I only have one bulkhead but it definitely defined the shape amidships. Hspira says "but i would not agree that forcing the forms in to acheive the design shape (vs letting the hull take its natural shape) is a problem or causes undue difficulty when you need to attach the hull to the deck." Agree. 
 

Have fun!

George K

Thanks enveryone for confirming my thoughts on this.  A few of the forms were definately pushing the sides out too much.  I was able to use a wrasp to get a better fit.  I still think #10 behind the aft bulkhead pushes the sides out more than I'd like but it sounds like this can be somewhat expected.  Prior to modifying them several forms had to be pushed into place with so much force you could not hold them in place to hot glue without them popping up.

All the forms are installed and ready for strips.  I shall begin that today.