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Tim G. 05-12-2004 03:25 PM

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.:D

IDRPSTF 05-12-2004 03:31 PM

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?

IDRPSTF 05-12-2004 03:33 PM

Oh My God!!! I am going back to 2nd grade english class, sorry for the spelling guys!

LudvaBMW 05-12-2004 03:42 PM

Tim G.



Maximum engine rpm are 6500 speed in a minute
Transmission Z drive is 1.47:1
Z drive is alpha one 2 generation

I'm sorry but somehow me falled internet
Must have been switch to reserve

JUSTONCE 05-12-2004 03:44 PM

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.

LudvaBMW 05-12-2004 03:48 PM

IDRPSTF



Much the I don't understand could me it write registrar(Grammatically ?)

I'm sorry

LudvaBMW 05-12-2004 03:55 PM

Originally I in boats had motor mercruiser 5.7l
A hundredth all propeller me it rode 72km
A weight craft was about 500kg smaller

Tim G. 05-12-2004 04:00 PM

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 $.

LudvaBMW 05-12-2004 04:09 PM

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

LudvaBMW 05-12-2004 04:19 PM

Tia G.

Gyroscopic moment has 560nm
Aluminous propeller at our place costs from 350 $.
But perhaps bad range


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