The effect of an explosion due to the rupture of a pressurized sphere, centered at the ocean surface, is determined. The field of disturbance near the vertical axis through the center of the explosion is determined by Friedman's analytic approach, based on a perturbation of the linear‐shock‐tube solution. The interaction of the main blast wave with the ocean surface is determined by fitting a locally plane shock with a Prandtl‐Meyer expansion, which reduces the shock pressure to atmospheric value. The main object of the calculation is to determine the shape of the distorted ocean surface (or crater). Calculations are made for initial sphere pressures of 619 and 7000 atm, respectively. The shape of the disturbed ocean surface flattens at the base as the strength of the explosion increases, in agreement with the behavior found for intense point source explosions.