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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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

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


---
Remove x's to send.

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..

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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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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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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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..

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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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