Originally published by the U.S. Navy in 1946, "The Fleet Type Submarine" uses the USS Perch SS313 to explain operating principles, technologies, and systems. It contains numerous diagrams and photos and offers definitions of components and terminology. It provides technical descriptions of various machinery and systems such as ballast tanks, trim, ventilation and steering. It also contains a brief history of the submarine and a discussion of patrol routines. By far this is the most complete technical guide to the boats that won WWII in the Pacific. Nothing close to it was ever assembled before, or since. Periscopefilm.com's affordable reprint comes in a soft bound edition with attractive covers. Although some of the book has been reformatted, and color images are reproduced in black and white, all of the original content is preserved. This is a must-have for anyone interested in submarines and an important reference for any historian, docent, or modeler.