Depending on what you like to achieve probably? It sounds pretty good to me already. If it was me I would go for as little pitch as possible to try to make the propeller as efficient as possible. But I would be more interested in power to drive into wind and/or waves than try to get the highest speed possible. Would be really interesting to see what it will do with efficiency when you increase the pitch.?
44 ft catamaran
Max prop easy18 in diameter 4 blade pitch is adjustable 16 to 24 degrees
72 volt 18 kw motor, max RPM 1200
Reductions =90-tooth bottom?pulley 28-tooth?top pulley = 3.21:1 ratio
39.5ft waterline-hull speed is close 7.8 to 8.4 knots
I think the reduction is too much, I would like advice on what to set the pitch to.
