The Nmea2Wifi and Nmea4Wifi multiplexers can read the SeaTalk1 bus and convert the datagrams that travel on the bus to Nmea0183 sentences. Then the converted sentences can be sent out serially or by Wifi. The connection is shown in the following picture:
Depending on the length of the SeaTalk1 bus, ambient electrical noise and other factors, it could be the case that the waveform that arrives to the multiplexers is not sufficient clean to allow proper operation. If you find erratic readings the inclusion of a filter as shown in the picture can solve the problem.