Hi Alex,
I have found the method described in Underhill’s Plank on Frame to work very well and highly satisfying once you get the hang of it. Have another look at Vol 1, Chapter 3. The meat of it begins at the bottom of page 61 and Sketches 44 and 45 help a lot.
I think the book is largely aimed at static modellers but with some adjustments the method can be adapted to larger planks.
I didn’t find it easy to obtain proportional dividers at a reasonable price but I’m sure, with t’internet you will be able to track some down- they are key to this method.
If you mean Scarbh which was a recent Jim Pottinger drawing, the hull was bright finished which might be a bit of a challengr for a beginning model. It might be easier to start with something with a blocked bow and stern making the planking easier.
This is an enlarged Vic Smeed Silver Mist planked in cedar with blocked bow and stern. The plank ends can get quite small and hard to attach if they go right to the ends.
Anyway, good luck- there’s nothing like the satisfaction of seeing a boat shape coming together from flat pieces of wood.
If you have any further questions, I or many other users of this forum, will surely be happy to help.
All the best,
Ian