Joe, on a boat that large, outboards are not a good choice. They cost almost as much as diesels in the larger sizes, they are not as efficient in pushing at lower speeds or fuel power conversion, etc. They are best on plaining hulls. I personally don't want gas on my boat, but the safety thing is individual. If you are thinking you want outboards to save space, think about "sail drives" where the engine sits on top of the fixed foot similar to an outboard. They are common on sail boats and Yanmar has some good ones, Volvo has them too. I don't know how large they get, but have the reliability of diesel and take up very little room. It's a good way to go on a trawler. Inboatd/outdrive is another way to save space, but doesn't lend itself to the normal stern transom on a cat. These are available in diesel and can tilt up to some degree, but are generally not as durable as sail drives. Volvo and Conrad have these. Good luck with your search.