The issue is not the wire used, rather how the circuit is wired. With all due respect to your colleagues, unless they are familiar with wiring in a marine environment they may not be aware of some of the nuances of wiring AC and DC circuits in a boat. A lot of the theory and practice will be applicable, but how the circuits are connected are different than in land based applications.Thanks for the feedback. I have done some research on this. I am also a mechanical engineering professor and passed my plan by some of the electrical engineering profs in my building. It would not hurt for me to get some feed back from marine electricians though. As a summary, I have a Furrion F30INR 30 amp shore plug that I plan on installing. From the plug I will use 10/3 gauge AC triplex round tinned copper marine cable that will be wired to a Newmar 30-amp AC breaker. I will then use 12/3 gage wire (same as the 10/3 gage) to connect to a gcfi receptacle. A second receptacle with a switch will be connected to the gcfi receptacle. The plug with the switch will be used to power the NOCO genuis 5amp smart marine charger.
Charlie Wing's Boat Owners Illustrated Electrical Handbook (amazon link) is a good introduction, as are Nigel Calder's books.