AbstractThe facilities and methods in use at Nobel's Explosives Company Ltd. for assessing explosive potential by the underwater method are described. Quantities measured include the velocity of detonation, the bubble period, the maximum bubble radius and the pressure‐time signature of the shock wave. From these, shock and bubble energies can be deduced and used as figures of merit for the material under test.Results obtained in this way for a variety of types of explosive are summarized and their significance as an index of performance is discussed.