We have measured the Newtonian gravitational constant using the ocean as an attracting mass and a research submersible as a platform for gravity measurements. Gravitational acceleration was measured along four continuous profiles to depths of 5000 m with a resolution of 0.1 mGal. These data, combined with satellite altimetry, sea surface and seafloor gravity measurements, and seafloor bathymetry, yield an estimate of G=(6.677±0.013)×${10}^{\mathrm{-}11}$ ${\mathrm{m}}^3$ ${\mathrm{s}}^{\mathrm{-}2}$ ${\mathrm{kg}}^{\mathrm{-}1}$; the fractional uncertainty is 2 parts in 1000. Within this accuracy, the submarine value for G is consistent with laboratory determinations.

• Received 5 August 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.3051