A few years ago I purchased plans from Uncle John's General Store online . In the summer of 2014 I finally got around to building a pirogue from them.
It is built it with four ribs and to the maximum length you get if you scarf two sheets of 1/4 inch plywood together, so it is just under 16 feet long. It is easy to load with two people, but a bit cumbersome for one person. I think the next time maybe will use 1/8 plywood for the sides, and maybe the bottom as well, and keep it under fourteen feet. That would reduce the capacity it can carry but improve the capacity for carrying it.
It was built in less than four hours any one day over a six day stretch. It is nothing fancy with me treating it as a proof of concept, rather than a final draft. The rub rail was a single piece of spruce ripped from a 1 by 4 to yield two rub rails and a centre keel of about 3/4" by 3/4" to help the flat bottom track better.
Assembly was done with brass flathead screws, left in place, and Titebond II glue.
The outside corners and scarf joints were done with epoxy resin and six ounce cloth. The inside corners were done first with long strand body filler and then epoxy resin and six ounce cloth.
Inside and out were primed and then painted with exterior latex paint.