In mid-1974 a test was made in the Gulf of Mexico of a LaCoste and Romberg inertial system for the measurement of the Eötvös correction for shipboard gravity meters. Since the system is designed for operation with satellite navigation, inertial velocities were updated at 2- to 3-hour intervals, using Lorac information because no satellite information was available. Two types of comparison were made between the inertial and Lorac data. One comparison was the rms difference between results from the two methods—0.46 knot, which corresponds to 3.0 mgal at a latitude of 30 degrees. The other comparison related to noise which could be mistaken for anomalies of interest in oil exploration. The comparison indicated that such noise in the inertial data was only about one third that in the Lorac data.