This is from v 38 (1954) of Motor Boating's Ideal series for backyard builders. They are well-known and their designs appear in most of the boating mags. Not sure anyone is interested but I am selling these books and thought I'd better do this now. There is a great series of books, 1 with Hacker's designs fr speed boats, and of course, these are all great sources for modellers as the complete info is here.