Logo
FULL SITE MENU

Not sure what prop I need, can I get some advice?

T

tdelam

New member
I have a new boat 16' Legend XTR 16 with a 90 mercury on it. I am looking for a little more speed. I was reading some pitches and stuff can help. I get about 42 mph now. Any tips on what prop I can/should get for some extra speed?
 
What rpm's is it getting to at full throttle now?

Changing the pitch effects the rpms and you don't want the motor to operate outside of it's WOT range (specified in your owners manual).

So if your motor has a range of say 5000-5500 rpms and your current prop, at max throttle is making say 5200 rpms then you are smack in the range and it's about as good as it's going to get.

If you are below that range then you have "too much pitch" (or diameter) and you would need less pitch.

If you were at your max range (5500 in my example) or even a little more, you could go with more pitch.

Changing the pitch by 1 changes the rpms by about 200 rpms - so if you have a 14 pitch and you are getting 5200 rpms, going to a 15 would take that down to 5000 rpms - moving down to a 13 pitch would increase the rpms to 5400.

And yes, changing pitch will effect the speed but often not by an amount that you would notice unless your current prop is totally wrong.

And given your current set-up, 42 mph on a 16 foot legend sounds pretty good - what are your expectations?
 
Agree 100% if you want faster get a bigger engine. Putting a prop with more pitch will effect the hole shot as well. Lugging a outboard will reduce its service life also.
 
Full windshield or side console??? 2 or 4 stroke 90hp? Stainless or aluminum prop? Boat design,engine type,mounting height also help determine prop pitch/diameter/blade type.
 
galamb said:
What rpm's is it getting to at full throttle now?

Changing the pitch effects the rpms and you don't want the motor to operate outside of it's WOT range (specified in your owners manual).

So if your motor has a range of say 5000-5500 rpms and your current prop, at max throttle is making say 5200 rpms then you are smack in the range and it's about as good as it's going to get.

If you are below that range then you have "too much pitch" (or diameter) and you would need less pitch.

If you were at your max range (5500 in my example) or even a little more, you could go with more pitch.

Changing the pitch by 1 changes the rpms by about 200 rpms - so if you have a 14 pitch and you are getting 5200 rpms, going to a 15 would take that down to 5000 rpms - moving down to a 13 pitch would increase the rpms to 5400.

And yes, changing pitch will effect the speed but often not by an amount that you would notice unless your current prop is totally wrong.

And given your current set-up, 42 mph on a 16 foot legend sounds pretty good - what are your expectations?
Click to expand...

Excellent info! Thanks. I believe I am getting 5000 rpm's, I 'll have to check when I am out this weekend. I am aware 42 mph is pretty good and not really "expecting" per se but like most people, theres always the want for more speed/power. The boat is rated for a max 90 and thats what I have on it.

Thanks for the info!
 
Back
Top