I don't know anyone who runs a Sharrow. I had read a way back that Yamaha either worked out a partnership or acquired a stake (majority?) in Sharrow. At that time the props were listed at about $5,000. The cost was significant but the Yamaha deal was supposed to bring the price down. Reviews at that time contrary to the above Boat Test article led me to believe that the appropriate market for the new prop was commercial lower seped vessesl.
My concern is cost but also the threat of theft. A several thousand dollar prop would be an attractive target for crime.
There's a youtube video from florida where a guy had my boat A Grady Seafarer and put a sharrow on. Had no effiency gains, but planed out at a lower rpm like a 4 blade prop. Total waste for a rec boat. He was so detailed with the numbers that Sharrow sent a guy to his house to dial in the numbers and try to get better. I think they saw tiny gains.
Massive cost for minor gain. Here's the updated video with Sharrows comments. They were displeased with the first one.
Powertech and a revolutionary 5 blade that is showing huge gains with another youtube channel on a Yamaha 300 on a ranger tug. Not sure if they sell it yet.