Reply To: Autohelm Dufour 35C

Jeremy Rowley

    Hi Ronan,

    Yes I think you have the Rotavecta wind unit, designed for motor boats.

    Regarding your query on NMEA/Seatalk. The wind vane is directly wired into the back of display unit, it is neither NMEA or Seatalk. The display unit interprets the signals directly from the windvane. Seatalk is a databus that allows connected to share data. For instance the speed instrunment will share speed via Seatalk, such that the wind instrument can calculate true wind speed and direction. Similarly all instruments will transmit all the data over Seatalk to a Chartplotter, or any other intrument that needs it.

    Changing from Seatalk to other databus formats is whole new subject altogether. If you wanted to go from SeaTalk to NMEA2000. You would need a Seatalk to SeatalkNG converter and then SeatalkNG to NMEA2000 converter (there does not appear to be a Seatalk to NMEA2000 converter available) There is potential for all sorts of interface problems by going this route and probably best avoided.

    For your information: Seatalk and SeatalkNG are not compatable with each other. They work at completely different data rates and the message formats are a different.

    Also, SeatalkNG is a Raymarine version of NMEA2000 which runs over a CANBUS system (designed for cars and trucks). CANBUS is a high-speed 115Kb baud binary data stream that has to be decoded into message format by each connected device. NMEA2000 and SeatalkNG although similar, are not compatible with each other. This is because Raymarine chose to make their datastream proprietary, whereas NMEA2000 is designed as ‘open’ system, so that multi-vendor equipment can talk to each other. This is why a SeatalkNG/NMEA2000 converter is required. Some of the later Raymarine plotters have SeatalkNG and a separate NMEA2000 interface.

    I hope this helps.