The inverter you are leaning towards is for home and office use. You need one for mobile (marine/RV) use. I don't see a ground relay mentioned, do you?
Maybe you should take a look at this book before you proceed
http://www.amazon.com/Boatowners-Mec.../dp/0071432388
Nigel Calder is the authority on the subject and could spare you from causing a very dangerous situation.