The DL21 Speed Log is designed for ships over 50.000 GT with simultaneous and independent measurement of speed through water and speed over ground to comply with the requirements of MSC.334(90), amendments to performance standards for devices to measure and indicate speed and distance. The SKIPPER DL 21 is working on the Doppler principle, providing Speed through water (STW) and Speed over ground (SOG) in 2 axis. The DL21 present the critical parameters on 2 independent screens and can be interfaced with bridge systems and repeaters. The DL 21 can also present distance traveled, depth and water temperature. The DL 2 can measure the speed of the vessel through the water in depths more than 3m, and Speed over ground in depths from 2m to 150 m. The sensor is mounted in a 100mm Sea Valve.