Luckily I asked first, because I saw in the guide that the GP330B can use 24V, while the PG700 only has 12V, thank you for the explanationNo you cannot. NMEA 2000 is 9-16VDC only.
Several companies make nice, affordable, 24VDC - 12VDC isolated power conditioners/converters. Ensure that you use an isolated model or you will have a ground loop. Connect the NMEA 2000 Net-C (DC-) and shield wires together to the isolated 12VDC -.
Thanks jp498I was just on a boat with 24v going into the NMEA2000 network. It was just some simrad AP parts with no long runs or heavy LENs. Simrad had nothing in their instructions about what voltages are OK. The customer was lucky it didn't fry anything. I put a converter in to bring it down to 12v because I wanted to add a Furuno if-nmea2k2 which 12v and a Furuno sat compass which specified 9-16v. NMEA2000 is supposed to be something common to everything and that means running on 12v-ish.