A novel method for computing ray paths of underwater sound for a given vertical distribution of sound velocity or temperature is presented. Equations for computing ray paths, an equation for obtaining sound intensities and an equation for determining locations of focal points are so integrated as to obtain results of adequate accuracy with minimum of redundancy and labor. Features of this method are enumerated as follows: (1) It is assumed, as usual, the propagating media may be divided into horizontal layers, in each of which the velocity gradient remains constant. It is not necessary, however, to compute values of velocity gradients itself. (2) All computations can be done on a nomograph and a slide rule without use of elaborate tables and desk calculators. (3) Subdivided horizontal layers may be added later to determine more precisely the configuration of a sound ray path without any interference to the previous computation. (4) Not only configurations of ray paths but also sound intensities, spreading loss, focussing effects, deviations from the inverse square law, equi-intensity lines and so on can be easily obtained. (5) Temperature distributions measured by a bathythermograqh can be directly used for computation without an intermediate conversion to velocity distribution, provided that depth and salinity corrections may be neglected. Detailed procedures of computation and a numerical example are described.
