The Office of Naval Research funded a project with the Scripps Institute of Oceanography for the theoretical design of a prototype decompression analog computer. The Foxboro Decomputer, Mark I was manufactured by the Foxboro Company and evaluated by the US Navy Experimental Diving Unit in 1957. Confusion between the diffusivity coefficient and the then new concept of tissue half time resulted in a device that did not properly mirror decompression status. Had this error not occurred, the U.S. Navy Tables might never have been developed, and divers might have been using instrumentation to control their dives from 1957 on.