One GOOD gas rumor!
#61
Performance Boat Center
VIP Member
19 pitch now?
The drive is probably an Alpha.
I would say to try a 17 pitch.
The boat should gather speed faster, and get more RPM at WFO.
You will probably need 15 pitch if you want to see 6,000rpm.
Das good.
The drive is probably an Alpha.
I would say to try a 17 pitch.
The boat should gather speed faster, and get more RPM at WFO.
You will probably need 15 pitch if you want to see 6,000rpm.
Das good.
__________________
Tim Gallagher
Performance Boat Center-FL
[email protected]
954-809-8739
Wright Performance, MTI, Cigarette, Sunsation
Tim Gallagher
Performance Boat Center-FL
[email protected]
954-809-8739
Wright Performance, MTI, Cigarette, Sunsation
#62
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Join Date: Sep 2001
Location: In your driveway while you sleep
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Is it me or does the prop math = a 2 pitch prop?
Hes running 4850 out of 6600 with a 19.
Averadging 100rpm per 1"pitch (Very rough average) that comes out to 1.5" to 2". WTF?
Even if you doubled the numbers to get 2" per 100 rpm, you are looking at about an8. There must be a bog down curve?
How fast does the boat get on plane?
At speed, does the prop act as a break when pulled all the way back, or does the boat just cruise to a stop?
Hes running 4850 out of 6600 with a 19.
Averadging 100rpm per 1"pitch (Very rough average) that comes out to 1.5" to 2". WTF?
Even if you doubled the numbers to get 2" per 100 rpm, you are looking at about an8. There must be a bog down curve?
How fast does the boat get on plane?
At speed, does the prop act as a break when pulled all the way back, or does the boat just cruise to a stop?
#65
Registered
I'd agree with you but I can't see propping mujch smaller than a 17 with that motor. I'm curious to what gear ratio your drive is, cause It doesn't add up to me to be a 1.5:1
Only thing I can think of is that the perticular motor is not Ideal for a boat because of the torque curve. It may lack enough high rpm torque to spin the prop you need over that rpm. If thats the case you are going to comprimise pitch severly just to spin the motor where it mneeds to be, maybe changing to a taller drive ratio wouldn't be a bad idea.
Only thing I can think of is that the perticular motor is not Ideal for a boat because of the torque curve. It may lack enough high rpm torque to spin the prop you need over that rpm. If thats the case you are going to comprimise pitch severly just to spin the motor where it mneeds to be, maybe changing to a taller drive ratio wouldn't be a bad idea.
Last edited by JUST ONCE; 05-12-2004 at 03:47 PM.
#68
Performance Boat Center
VIP Member
Yes I agree. I did have an Alpha with 1.47 gears.
I think that that engine just does not have much torque (nm) to pull rpm with that boat weight.
I would try the 17 pitch.
Aluminum propellers are cheap $.
I think that that engine just does not have much torque (nm) to pull rpm with that boat weight.
I would try the 17 pitch.
Aluminum propellers are cheap $.
__________________
Tim Gallagher
Performance Boat Center-FL
[email protected]
954-809-8739
Wright Performance, MTI, Cigarette, Sunsation
Tim Gallagher
Performance Boat Center-FL
[email protected]
954-809-8739
Wright Performance, MTI, Cigarette, Sunsation
#69
Guest
Posts: n/a
IDRPSTF
If it well comprehend ask behind how long cross over ship to the slippage.?
Abided it thereabouts 5 - 8 seconds but I don't know it exactly
I was trying another propeller size 19 but other rise,to have been better but ship rode only 82km
and to have been some if I trimoval or no,rode it in the same way and Z drive quite down
As I mounted trim tabs
So it improved
Maximum speed stayed same
If it well comprehend ask behind how long cross over ship to the slippage.?
Abided it thereabouts 5 - 8 seconds but I don't know it exactly
I was trying another propeller size 19 but other rise,to have been better but ship rode only 82km
and to have been some if I trimoval or no,rode it in the same way and Z drive quite down
As I mounted trim tabs
So it improved
Maximum speed stayed same