NAVAL architecture and aeronautics are compared to show what each has learned from the other. Design and performance of airplanes, seaplanes, flying boats, airships, hydroplanes, steamships, and sail boats are discussed as examples of this exchange of benefits, giving the relative advantages and disadvantages of each type.
The outstanding performance record of the Graf Zeppelin is cited as proof that the airship is more suitable than is the airplane for long-range oceanic transport.
Submerged hydrovanes for hydroplanes, seaplanes, and flying boats, with their advantages and disadvantages, are discussed at length.
An aeronautical method of analysis is used to explain why some yachts are closer-winded than others with similar sails and rigging.