Production power catamarans and tunnel hull powerboats semi displacement and high speed ocean limo plans to revolutionize the power catamaran and. Home / boat plans & kits catalog / be sure to check out these sections if you are interested in designs for outboard power. a word about power catamarans. Specmar catamaran hulls are either symmetrical or asymmetrical in design. a symmetrical hull consists of two basic v-bottom hull structures. asymmetrical hulls are.