Colin,
I completely agree. There has been a recent thread in this NG on this very
subject. See www.gridconnect.com Their serial to Ethernet gateway products
should be just what you are looking for and they are DC powered. These
completely eliminate the typical NMEA distribution hassle. Please also note
that there are appropriate ruggedized and moisture resistant CAT5 connectors
also available suitable to the marine environment as well.
Steve

wrote in message
...
In the commercial marine and Megayacht world CAT 5 runs everywhere on
these boats connecting PLC's to enterntainment systems, to
communication systems right into PC based NAV. Most of this is based
on industrial standards rather then marine standards. It works well
with off the shelf componets that are equally priced to NMEA pieces. I
would like to see a NMEA gateway to another protocol (other then PC)
to allow us to use NMEA 200 data on some of the other equipment
already on these large yachts.