Accuracy of hull dimensions vs performance

[flightofone]

I'm looking at copying an existing high-performance hull design, and am curious about how accurate the dimensioning needs to be before performance is adversely impacted. In particular, I'm using a CNC-routed female mold for which I can hold tolerances within about 4mm of the original shape, 2mm in small-radius areas. This is for a sailboat mono-hull on the order of 20m. Does anyone have non-anecdotal feedback on this topic?
Thanks!

[Willallison]

Given that this is a place frequented by professional designers, who earn their living from designing such boats, wouldn't you consider it to be ...err... inappropriate to ask them how to copy them?

There's more to a succesful design than just the shape of the shell. I suggest you pay the extra few $ and employ someone to design a boat for you legitimately

[tom28571]

Hey Will,

Given that he can only hold tolerance to +/- 4mm, I would not worry too much about copying. If it's starting with a high performance planing boat, the end result is likely to be a low performance slug anyway.

You are right, of course.

[Gilbert]

Here we go again.
There is copying and there is copying.
Why do most of today's boats look like they come from the same man's brain?
Well, duh, its because there is a lot of copying going on. And I'm not talking about amateurs.
By definition an amateur is someone who does something for pleasure and also might not be particularly skillful. But I have seen boats built by amatuers
that could only be produced at extremely high cost by professionals; because the professionals have to be paid. The amateur does not have to be paid and so can lavish his hours on his project. I have also seen amateurs whose skill level is VERY high; better than MANY pros.
So if someone wants to design and build his own boat and can afford to take the risk of failure let him have at it.

[Willallison]

Gilbert, there's a vast difference between copying some of the styling features and making an exact copy of a design. Put it simply, one is legal, the other isn't.

[Gilbert]

I assume the boat is for the builder himself not for a business venture competing with the original.
And by the way, flightofone, is the boat 2 meters or 20 meters?
If it is 20 meters you may have a whole lifetime of boatbuilding ahead of you if you do it yourself. Even if you are very young.