In a joint sea test of the Naval Research Laboratory, the White Oak Laboratory has obtained nearfield explosion data from 8‐, 48‐, and 1000‐lb TNT charges. Pressure‐time measurements at constant range were made, with multigain recordings at two depths. Recordings were made using both a ceramic hydrophone and a tourmaline piezoelectric gage. The experiment will be described and experimental data presented. These shallow depth‐constant range data validate previous results for underwater explosion similitude expressions for pressure, decay constant, etc., that were largely obtained from data where range and depth effects were intertwined. The data also extends to shallower depths the reduced parameter curves currently employed for predicting underwater explosion effects and for modeling acoustic source levels. Discussion will focus on how comparison of various records are useful for comparing different sensor outputs and for studying nonlinear effects—factors that influence source level determination. [This work was funded by DNA.]