Im looking to put a different prop on my boat to maximize the power. What is a best size to gain some speed and or power? Im new to this stuff. I appreciate it!
Prop pitch is measured in inches and is the distance the prop moves forward in one revolution.
Selecting a prop is like selecting a single gear in your car to do everything.
Putting it very basically to increase power you would reduce pitch.Its easier for the motor to turn
but moves forward less per revolution "Usually" reduces speed but increases rpm and power.
Increasing pitch lowers power and rpm(harder to turn)but can increase speed if the motor can turn it fast enough.
Motors are designed to operate within an RPM range your 4.3 is probably about 4400-4800.
The idea is to prop for the best performance for your typical load and activities within that rpm range.
Some times its necessary to have 2 props one for speed and one for power.
We'll be glad to help you through this confusing morass.
If you read the stickys at the top of the prop forum it may help.
Remember there are no stupid questions everyone has to start somewhere.
Prop pitch is measured in inches and is the distance the prop moves forward in one revolution.
Selecting a prop is like selecting a single gear in your car to do everything.
Putting it very basically to increase power you would reduce pitch.Its easier for the motor to turn
but moves forward less per revolution "Usually" reduces speed but increases rpm and power.
Increasing pitch lowers power and rpm(harder to turn)but can increase speed if the motor can turn it fast enough.
Motors are designed to operate within an RPM range your 4.3 is probably about 4400-4800.
The idea is to prop for the best performance for your typical load and activities within that rpm range.
Some times its necessary to have 2 props one for speed and one for power.
We'll be glad to help you through this confusing morass.
If you read the stickys at the top of the prop forum it may help.
Remember there are no stupid questions everyone has to start somewhere.
Thanks for all of that info. It helps. Still confused though :lol: I guess I was looking for the best all around prop but I suppose I need to decide whether I want more speed or more power. I do a bit of everything. I do pull tubes from time to time but I probably do more cruising than anything. So should I get back to you with my WOT RPM's or can you help me with the info I have given. I know its not very helpful info but maybe you can understand what im shooting for? Thanks again for the help!
By the way, I have a 2005 Maxum 1800 SR3. Its an 18' boat. Just bought it on Friday. Pretty excited about it. Just got rid of my old 89 Crownline Celebrity for this! On the test drive I got it to 45 MPH. Didnt look at RPM's. Today I got it to about 38 but had 1 extra person and it was a bit choppy.
To evaluate your setup we need your prop size (near the base of the blades or under the prop nut).
We need your lightly loaded wide open throttle(wot)rpm and speed,by gps is best,.We need to know
the hp and or the gear ratio Usually on the outdrive.
There are props that are a reasonable compromise that will depend on your present performance.
I have about the same size boat only older (1994). I went from a dinged up aluminum 3 blade 19p to a brand new aluminum 4 blade 18p. 3 blade=45 by myself; 37mph with 5 people. 4 blade= 38 with 4 people (haven't run it by myself). Hole shot with the 4 blade is incredible. I mean no bow rise at all. I'm getting the 3 blade refinished so I'm interested to see it's new top speed. Hoping probably around 47mph.
If you can, try a 21p 4 blade from a dealer or a friend. I believe that will give you hole shot and top end perfection.
To evaluate your setup we need your prop size (near the base of the blades or under the prop nut).
We need your lightly loaded wide open throttle(wot)rpm and speed,by gps is best,.We need to know
the hp and or the gear ratio Usually on the outdrive.
There are props that are a reasonable compromise that will depend on your present performance.
Ok Ill get those things to you when I can. I noticed when I ran the boat this weekend any speed 20 MPH and under when cruising the front end would rise and not stay planed. That sucks! I definitely want it to stay planed out when cruising and want it to stay planed when I pull people. Havent got to pull anyone yet but if thats how it is when im cruising then pulling will be worse im sure. Hopefully a prop will fix that?
I have about the same size boat only older (1994). I went from a dinged up aluminum 3 blade 19p to a brand new aluminum 4 blade 18p. 3 blade=45 by myself; 37mph with 5 people. 4 blade= 38 with 4 people (haven't run it by myself). Hole shot with the 4 blade is incredible. I mean no bow rise at all. I'm getting the 3 blade refinished so I'm interested to see it's new top speed. Hoping probably around 47mph.
If you can, try a 21p 4 blade from a dealer or a friend. I believe that will give you hole shot and top end perfection.
