Many thanks for your help In the setup of my 46" Fire boat,it has a prop fitted already, a three bladed brass 60mm. I tried It out at our club on Sunday, BMMMC Bury,Lancs. I used the 40 esc as you suggested, but only fitted a 15amp fuse which It blew after 5 mins run, I think I have a problem with the propshaft as It jammed which Is why the fuse blew, I think a replacement will be needed and will try a 40mm two blad prop this weekend, will keep you Informed as to the outcome. Also at the club meet was a guy with the same 46" Fire boat, but with a brush-less setup, he had a 1800rpm motor with a 120amp esc powered by 500mah 6 cell lipo, very quick!! also at our club who gave me some useful Info on motor/esc setup was Pete Barrow, who Is a world champion power boat guy, have you heard of him? really helpful sort of person, very much like yourself.....many thanks.