I'm sure everyone is familiar with the "How to Build 20 Boats" series
formerly published by Fawcett Publications, with lots of individuals
on eBay making a buck or two selling CD's of the plans, but I have
found another, more contemporary source of plans in the "Sports Afield
Boatbuilding Annual". They are not public domain, to my knowledge, but
several in the series are readily available through various book
searches. They were published from 1954 to 1966, featuring plans by
Weston Farmer, Edson I Schock, Bruce Crandall, and others. A couple of
the issues have fold out plans, but all the boats have detailed plans
with the articles. And, the plans are not repeated in multiple years!

I'm still getting familiar with them, but included are Weston Farmer's
Simplex, and Bayou Belle
houseboat, to name two - ten plans per issue, or so.

Frank