Hydrographic Survey Vessel

A hydrographic survey vessel measures water depth and maps the seabed for nautical charting, using multibeam echo sounders, side-scan sonar, sub-bottom profilers, and positioning corrected by GNSS and sound-velocity profiles. Surveys are graded against IHO Standards for Hydrographic Surveys, Special Publication S-44 (6th edition, 2020), which sets order-by-order limits on horizontal and vertical uncertainty and feature detection. Charting data follows the S-100 universal hydrographic data model and the S-101 electronic navigational chart product specification. National hydrographic offices, such as the UK Hydrographic Office, task these vessels to keep charts current.