Speed Logs Information
Speed Logs are data logging devices that measure a vessels speed through water or longitudinal and fore/aft transversal ship speed relative to the sea bed. (Speed over ground (SOG)). Both Speed over ground and speed through water devices are required on all cargo vessels of 50,000 GT or greater and passenger vessels 300 GT or greater that are constructed after July 1, 2014 per SOLAS regulation V/19.2 and SOLAS regulation V/22.214.171.124.
Common types of speed logs include:
GPS (Global Positioning System)
BS ISO 16329 - Ships and marine technology - Heading control systems for high-speed craft