Recent advances in the technique of submarine gravity surveying

The errors in gravity surveying at sea which are the most difficult to estimate are involved in position-finding, measurement of speed over the ground, the variations of depth-keeping and in the second-order correction. Submarine gravity surveying is also a slow process on account of the time required for an observation with the standard Vening Meinesz 3-pendulum apparatus and the complications of computing the result. During the recent cruise in the English Channel in May 1948 of H. M. SubmarineTalent most of these difficulties were overcome by the provision of special instruments which are described here. The most important of these was a stabilizer which, by automatically compensating the effect of side-ways accelerations on the pendulums, removed the necessity for certain tedious corrections and enabled the results to be rapidly computed.