The exact location and the depth of the very deepest spot remain topics of interest to the oceanographic research community. No one has claimed that a measurement of any maximal depth of the Challenger Deep (either by direct CTD pressure measurements or by ensonification) defines either the absolute deepest depth or the geophysical location of the deepest point in the Challenger Deep. Such a claim will require a survey of all three basins by both echosounders and pressure gauges, such that all depths are measured by one set of equipment and use the same correction calculations.