Hi i have a 9.9 Mercury with the gearchange in the throttle on the tiller, it has a high thrust plastic prop that can have the blades changed, im not sure of the pitch but would like to know what the best pitch would be to push a 25ft sail boat with twin keels, i know anything will push her but i'm looking to save fuel if poss and i'm assuming this prop i have is suited to boats on the plain. i normally run it at half revs and she will do around 3-4 notts depending on tide, would the highest pich be better to push and keep the revs down or should i increase the blades to four? any comments welcome thank you.
