I got my copy of Boat Strength in the mail. Gosh, it's hardcover. Editing has gotten looser than it used to be. In cursory reading I found two mistakes. Nothing fatal. Stuff like a missing hyphen when a word is broken at the end of a line and continued on the next. Still, it indicates that other errors could lurk in places where it matters. I'm nitpicking here. 15 years ago when I last had to deal with a publisher, the guy who was editing my book, The Aleutian Kayak was telling me how the publisher wanted them to edit more books every year. Ideally, from the publisher's standpoint, editors could be replaced by computers. I think the publishers are now trying to publish books with minimum human input other than that of the writer and it's starting to show.
On to substantive matters.
As I suspected, kayak builders can dispense with a book like this, but if you want to build anything more ambitious than a kayak, this book might be of help. Wooden boat building gets about a hundred pages. Fiberglass, steel and aluminum gets the rest. I suppose that if you wanted to build a kayak in steel plate, you might find some useful info in the metals section. But the books has various nuggets of useful info, like what kinds of aluminum alloys can withstand salt water, in case you want to build a George Dyson Aluminum frame type kayak.
There are other nuggets of wisdom in this book, like the tradeoffs between weight and strength and cost of various materials. For instance, aluminum is not as strong as steel, but is lighter so the strength of steel can be had by using thicker aluminum and total weight will still be less. But then aluminum costs a lot more than steel and the savings in weight come at a cost of more money. Nothing comes for free after all.
So, as I suspected, not a must have for kayak builders but a good addition for the library of someone with higher ambitions or a simple love of boat building knowledge.