The plank problem on banker dories is that they (the planks, garboards
especially) are very wide at the ends.....in excess of 12 inches on large
dories. If any glue is put between the laps the results will be disasterous
unless you are using plywood to "plank" the dory. I have built dories
using pine. A little 3M 5200 in the laps will help keep a dory from
leaking; even so, the fits have to be pretty good. Old time dory
construction called for NOTHING in the laps; that called for really good
woodwork and they still leaked.
Dave