There's an outfit, PropCo, IIRC, that sells 'reverse-cup' props for especially for houseboat outboards. We have found them to be pretty good for the job. Our two 60hp (high thrust) outboards make the beast pretty maneuverable, actually, especially when operated by people who know what they're doing. The Albemarle Boats guys who installed ours made it really dance. And admitted to being "extremely impressed."