Have a Yanmar 2GM 15 HP @3600 with 2.62:1 trans. Martec folder not working well and want to put on a fixed prop- likely 3 blade. Wonder what prop folks have used on this boat and how well it worked for them. Seems every prop manufacturer gives different numbers for the diameter and pitch as well...little confused by how to determine this. (although I've ordered a book on props...maybe that will have all the answers!)