I have a 2011 GLI that has a 115 Merc with a 2208 15 prop and two 25in pontoons. I am running 22mph GPS and turning 6400 RPM's according to the Tach. That is with 2 adults and full tank of fuel. It seems the RPM's are to high and was wondering if this is the best speed that I can expect. I was looking at the Spitfire 4 blade props in 17 pitch to lower the RPM's.Open to any suggestions and help. Thank you for any input and help.
Best prop options
- Thread starter ranger45
- Start date
cwag911
Moderator
iMHO, If you go from 3 to 4 blades and go up in pitch you'll lose a lot of rpms. 4 blade won't give you the speed of a 3 blade but it will give you better bite. Either do the 4 blade with the same pitch or 3 blade in 17p. Are you sure you're trimmed correctly?
I have tried trimming the motor while running WOT and there is very little difference with speed. Is that how it works the 3 blade usually run higher speeds/
cwag911
Moderator
A 3 blade will run more rpms than a 4 blade of the same pitch. Unless you have serious horsepower like race boats that run 4 and 5 blade props the 3 with extra cupping for a pontoon is the way to go. My $.02
ericscher
Well-Known Member
You could use some more pitch. Probably two whole numbers.
Link
Moderator
Ranger, you dont say what model your boat is but I have a fairly similar setup; RL2275 with 2 25" toons [no strakes] and a yamaha 115. My prop from the dealer was a 13.5 x 15 and I run at 5800rpm and get a consistant 27 on the GPS
Sorry about that it is a 2011 2274GLI. I can't get anywhere near that. I talked with a Mercury outboard factory rep and he suggested a Spitfire 13 x 17 prop. He told me they plane boat faster and hold cornering better.Has anyone else tried one?