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Josh Assing
 
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Default 21' larson prop size?

We just picked up a larson power boat - the PO said it had a "ski prop" on it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?

Thanks
-josh


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Matt Lang
 
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Josh Assing wrote in message . ..
We just picked up a larson power boat - the PO said it had a "ski prop" on it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?


It is true

Prop pitch is somewhat like gearing in a car. If you pull more
(skiing) you need to gear down (lower pitch prop) giving you more
torque and less topspeed.

If you are cruising with a light load you dont need lower gear/pitch
and can have a prop with high pitch and go faster.

Getting the right prop and the right prop for the day/application can
be quiet the quest...

Matt
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IBNFSHN
 
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To properly prop your boat you need to know what the WOT (wide open
throttle) range is for your motor. Then you need to know what RPM you now
turn (with a normal load) at WOT. It is usually just a matter of adjusting
the pitch up or down.

--
Bill
Chesapeake, Va


"Josh Assing" wrote in message
...
We just picked up a larson power boat - the PO said it had a "ski prop" on

it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for

engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?

Thanks
-josh


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Jack Redington
 
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Josh Assing wrote:
We just picked up a larson power boat - the PO said it had a "ski prop" on it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?

Thanks
-josh


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I bet by ski-prop they mean it has a lower pitch. Thus better whole shot
for popping out folks out of the water and dragging them less. You would
lose a little top end. As long as you don't run the boat in excess of
recomended rpm. It would be fine.

Capt Jack R..

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Josh Assing
 
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Prop pitch is somewhat like gearing in a car. If you pull more
(skiing) you need to gear down (lower pitch prop) giving you more
torque and less topspeed.


Hmm. I put a wrong prop on my fiberform years back and it just caused the boat
to "go fast" at idle; but at 1/2 throttle; it'd overheat & never go "faster"....
that's why I thought it was all designed "together"

If you are cruising with a light load you dont need lower gear/pitch
and can have a prop with high pitch and go faster.


and theoretically better fuel economy?


Getting the right prop and the right prop for the day/application can
be quiet the quest...


hmm. well; hopefully there's other Larson owners out there that can help....

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Josh Assing
 
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Thanks.

Now I just gotta figure out what the RPM range is & all that jazz.
I'd rather have better top end & fuel economy...

-josh

On Thu, 26 Aug 2004 21:33:03 GMT, Jack Redington
wrote:

Josh Assing wrote:
We just picked up a larson power boat - the PO said it had a "ski prop" on it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?

Thanks
-josh


---
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I bet by ski-prop they mean it has a lower pitch. Thus better whole shot
for popping out folks out of the water and dragging them less. You would
lose a little top end. As long as you don't run the boat in excess of
recomended rpm. It would be fine.

Capt Jack R..



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Josh Assing
 
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How do I find this information?

On Thu, 26 Aug 2004 16:58:34 -0400, "IBNFSHN" wrote:

To properly prop your boat you need to know what the WOT (wide open
throttle) range is for your motor. Then you need to know what RPM you now
turn (with a normal load) at WOT. It is usually just a matter of adjusting
the pitch up or down.



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Jack Redington
 
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Josh Assing wrote:

Thanks.

Now I just gotta figure out what the RPM range is & all that jazz.
I'd rather have better top end & fuel economy...

-josh

On Thu, 26 Aug 2004 21:33:03 GMT, Jack Redington
wrote:


Josh Assing wrote:

We just picked up a larson power boat - the PO said it had a "ski prop" on it;
but if we put the "stock" prop on; the boat would be faster....

I don't know much about props; but I thought props were 'designed' for engine &
boat -- and couldn't (shouldn't) be swapped about....

is this true? if so; what should the proper prop be for the boat?

Thanks
-josh


---
Remove x's to send.


I bet by ski-prop they mean it has a lower pitch. Thus better whole shot
for popping out folks out of the water and dragging them less. You would
lose a little top end. As long as you don't run the boat in excess of
recomended rpm. It would be fine.

Capt Jack R..




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The recomended rpm's (high end) will be with the manufactures
documentation. If you don't have it you can get it from whoever made the
power plant.

Capt Jack R..
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Josh Assing
 
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The recomended rpm's (high end) will be with the manufactures
documentation. If you don't have it you can get it from whoever made the
power plant.


Thanks -- I'll try to find them -- it's a mercruiser mcm 5.0litre "AlphaOne"
engine

cheers!
-josh

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trainfan1
 
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Josh Assing wrote:
-snip-



Getting the right prop and the right prop for the day/application can
be quiet the quest...



hmm. well; hopefully there's other Larson owners out there that can help....

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It really has little to do with being a Larson...

We have 3 different props for our Glastron, all for different days /
activities... I think you need to do some in depth research on prop
selection and not limit yourself to "21' Larson" owners...

Rob
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