In 1941, still at Cornell, he became a part-time consultant at the David Taylor Model Basin (DTMB), the United States Navy modelling facility. In the period 1946–49 he was the head of the hydromechanics laboratory, and from 1950 until 1957 he was head of the structural mechanics laboratory. From 1957 until his retirement in 1960 he was a general scientific consultant to the commanding officer of the DTMB. Also after his retirement he continued to work for the DTMB under contract. Much of his research for the Navy focussed on hydrodynamics and elasticity, in particular on the theory of potential flow, the physics of underwater explosions and structural vibrations.