The Speed Log System Wärtsilä SATLOG SLS 4120 measures Speed Over Ground (SOG), referenced to the ship’s axes, by using the input from a gyro compass. With a precision of greater than 0.2 knots or 2 % of speed. This accuracy is compliant with the IMO performance standard for Speed and Distance Measuring Devices (SDME) IEC 61023 and allows the Wärtsilä SATLOG SLS 4120 to be used as a speed log for ground stabilising applications or docking manoeuvres. Interfaces between the Display Unit, Electronic Unit and DGPS Sensor comply with IEC 61162.
Together with an EM-Log or other log sensor measuring the Speed Through Water (STW), the Wärtsilä SATLOG SLS 4120 becomes a central display for speed related information such as Speed Through Water and Speed Over Ground, as well as distances travelled.