Digging the channel for the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: "The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded." "The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet." The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.
