Thanks for help, spent little more time on the net, starting to get the picture(almost). Only downside with the NMEA 2000 system is that he transducers seams to be expensive.
LST-3800 gauge+transducer is priced in most places cheaper than a NMEA 2000 ARIMAR transducer alone? But well, it might be a god thing to have everything compatible for the future. Will do some thinking, as i need both, consider also a fish finder, it might be good to see the profile of the bottom, myriads of stones in these waters.
fun on a boat is inversely proportional to size...sort of anyway