I am sure the answer lies in several places here buried in some of the "thousand post" threads, but hopefully I can get just a quick general rule-of-thumb from the experts here. I have been offered a job near a beach city in South Carolina and am considering being a liveaboard on something like a 400 sedan bridge or possibly 390MY or something similar. Of course a trawler might be an option, but that's another topic. I can save a ton on the purchase price by getting gassers but know they will be thirsty pigs in boats this size. How much better fuel economy do the diesels really get in boats this size? For those of you that own either of those models, what do you get mpg? Looking for input from both gas and diesel owners to see the real world numbers and difference, thanks in advance.