The underway systems on the Australian Institute of Marine Science research vessels, the Solander and Cape Ferguson, are designed to routinely collect underway measurements of surface properties useful for environmental monitoring in tropical waters.  The instruments obtain underway observations of temperature, salinity, chlorophyll-a fluorescence, light absorption, and irradiance.  Data are collected in Great Barrier Reef waters, the western Coral Sea and off Western Australia, within repeated transects and individual voyage tracks.  Use of the underway sensors depends upon the operational schedules of the vessels and the capacity of users and crew to support the instruments while underway.