Came across this site. Check the section for surfboards the illustrations are kind of neat. Anybody want to guess how old they are? http://www.anyboat.com/books/bkltsail.htm#Surfboards
The illustration for the surfboard plans look like the Tom Blake design featured in Popular Mechanics. The lifeguard on the board even looks like him. The date for the PM article references a letter returned to Tom Blake on 11/8/38. I have a board that was made at Long Beach Jr High in 1938 by the man who gave it to me. I’d say late 30’s early 40’s is a reasonable guesstimate. Can you still order through that booklet?
I checked and apparently you can order through the company based in UK.