DIY Design for a comfort pleasure power catamaran

[irixzone]

I want to build a power catamaran for mostly recreational use. I am not too much concern about speed or performance, my goals are security and comfort. Because I want to put it on a trailer, I can exceed the 8.5 ft width, and my idea is to use a length of ~ 30 ft. Please help with some advice. I am not sure how stable is with only 8.5 ft width and 30 ft long. What is the best hull design for this case (sacrificing performance)? Thanks.