None of the McNarry books is currently in print, and used copies from the usual web sources tend to be pretty expensive. (In addition to the two books mentioned by Flitch, Mr. McNarry wrote one on Stuart yacht models. I believe that one was printed in an extremely small edition, primarily for distribution to friends and patrons. I've never seen a copy of it.) If you can get hole of a copy of any McNarry book - hang onto it!
In the U.S. a relatively convenient source for Underhill and Ough plans is Taubman Plans Service (www.taubmansonline.com). Abraham Taubman was for many years a legend among American ship modelers. He ran his own dealership, specializing in ship plans from just about any conceivable source, until he was well into his eighties. A few years ago he sold the business to some younger folks who incorporated into their ship model supply firm. Their online catalog contains literally thousands of plans. How many of them they actually have in stock, and how many they order from their suppliers when customers ask for them, I have no idea.
The prices of Underhill plans in the U.S. shot up drastically a few years ago. To my notion, those prices are now pretty outrageous. A high percentage of Underhill's drawings are reproduced in his books - notably Deep Water Sail, which has somewhere near a hundred fold-out drawings in the back. I'm a big fan of Underhill, but if I wanted to build a model on the basis of his drawings my first step would be to see whether that particular set appears in any of his books.
Taubman's Online also lists Norman Ough's wonderful warship drawings. Again, though, the prices are pretty high - and I don't know how many of them are actually in stock and how many have to be ordered by the dealers from England. I should emphasize, I guess, that I've never had occasion to order plans from the new owners of Taubman's. I did have a couple of e-mail exchanges with them a few years back; they seem like courteous, conscientious, and knowledgeable people. But I don't have any first-hand knowledge of the quality or speed of service they provide.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.