I've planked a lot of hulls, right now I'm working on the 4th ship's boat for the Vanguard model I'm building (link to my Vanguard build log in my signature line show's my work on those boats, its the most recent series of entries). In a lot of ways building a ships boat is harder than the hull because of the small size.
I start with the top most plank and work my way down. However, the second plank I install is the garboard plank at the keel. You're always going to have some fill even with the most perfect planking job. You want that fill to be on the bottom where it won't be seen. However you need a neat garboard to get a good clear match to the keel.
With the top plank (below the future cap rail) done and which should require splining and the bottom plank (garboard) done at the keel I start working top down. Splining and tapering to fit is not that difficult. Determine by counting how many planks it will take to fill top to bottom at the widest point, the waist of the ship. Measure the distance top to bottom at the bow between your top and bottom plank and divide by the total planks at the waist. Example if it will take 10 5mm planks at the waist to fill and your measurement is 5mm then the plank width at the bow needs to be 2mm. Its then just learning where to start the trim based on how it overlaps and use a standard Xacto knife and a metal ruler to do the trimming. Probably have to do the same thing at the stern. The comments about the trim and curve of the garboard above are correct, but I wouldn't stress much about that, its an easy trim and at the bottom of the boat not noticeable, especially after sanding and painting the final result.
I'm sure somewhere on this forum is a more detailed explanation of planking (I had a detailed tutorial here once, but it was lost in the great site crash). But the basics of working top to bottom and trimming so that every plank full width at the waist reaches the bow at a smaller width is the way to go. The little fill that leaves at the bottom between the last full plank and the garboard won't ever be seen.
Edited by Glenn, 29 December 2016 - 05:27 PM.