: I dunno about trivial, I'd feel bad if I got that far off cutting
: freehand; these guys should have a jig at the very least.

I know what you mean--but tables of offsets routinely go down only to eighths of an inch, and 16ths are simply designated as plus a bit or minus a bit.
Trying to bend wood chines to get accurate curves from points which are only approximate can cause different builders to come up with slightly different forms. How different? probably 1/16th to 1/8th inch. An aggressive day with a sander can affect the shape of the hull by that amount, too.

I think we overdo the number of frames we use. For the sake of convention we space them a foot apart for kayaks. With older plans for canoes they are frequently 18" apart. They only need to be at points where they will influence the bending of the strips. If this was a vector-based drawing we could call those "control points".

If I was making frames for a living, and couldn't afford to buy CAD/CAM equipment, I'd make hardboard templates and cut the forms with a router with a pattern bit.
it would be more consistent than cutting each set freehand, and much cheaper than CAD/CAM. Maybe their jig slipped.

PGJ