Wärtsilä SAM 4642

Wärtsilä SAM 4642 is a navigation 2 axis electromagnetic speed log for measuring longitudinal and transverse speed through water. A mile counter and a water temperature sensor is included. Speed information can be relayed to a radar, AIS, VDR and all other relevant devices via NMEA-format connections. Interfaces between the operator unit, electronic unit and sensor comply with IEC 61162 specifications. All relevant IMO requirements are met or exceeded.

    System Overview

    Transducer and Transceiver
    SAM 4642 sensor is connected to the electronic unit located within 40 m of the sensor. The connection from the sensor to the electronic unit is via a serial RS-422 data link as well as the connection from the electronic unit to the operator unit. The link between electronic unit and operator unit may be up to 300 m. Power supply is via 230 VAC/115 VAC or 24 VDC. The power consumption is approximately 100 Watts.

    Operator Unit
    The display is optimized for the intended purpose and consists of several numerical and alphanumerical LED segment displays. For user inputs six keys are available. For audible warnings the operator unit is equipped with a buzzer. The communication between operator unit and sensor is established as a bi-directional exchange of proprietary and standard NMEA telegrams via the Com-NMEA interface. The system can be calibrated from the operator unit. Optionally, Windows software for calibration via a laptop is available. The operator unit is normally console mounting. The dimension is international standard of 144 x 144 mm. A ruggedised housing for desktop mounting is also available. Operator unit power supply is 24 V DC. Power consumption is approximately 10 Watts.

    Standard functions
    Technical data
    Wärtsilä SAM 4642 Technical data
    Power supply 230 VAC (50/60 Hz), 24 VAC (50/60 Hz), 24 VDC
    Power consumption Max 100 W
    Speed range ± 40 kts in both axis
    Water track Less than 3 m below sensor
    Accuracy Complies with IEC 61023 / 0,2 Kn or 2 % whichever is greater
    Outputs 2 x NMEA 0183 / RS 422
    alarm relay output
    Sensor installation Tank or gate valve


    Wärtsilä SAM4642 and Wärtsilä SATLOG SLS 4120 combination to fulfill carriage requirements

    SOLAS adoption for carriage requirement resolution MSC.334(90) states that all ships constructed on or after 1 July 2014 and ≥ 50.000 GT are required to carry a separate speed log for measuring speed over the ground(SOG) additional to the speed through water log (STW).

    The Wärtsilä SAM4642 EM-Log (STW) and Wärtsilä SATLOG SLS 4120 (SOG) combination is a cost-efficient and type approved solution to fulfill these requirements.

    • Only one underwater transducer for the EM-Log is needed to determine the speed through water, the speed over ground is calculated using solely the GPS component.
    • Compared to conventional log systems our SATLOG SLS 4120 provides you with speed over ground information independent of water depth.

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