BoatBanter.com - View Single Post - Need help reading these used props I have...

Mr. Luddite

On 3/11/2014 2:19 AM, wrote:
On Tue, 11 Mar 2014 02:24:44 +0000, Charles Weitz
wrote:

My brother gave me these two props and I've had them for 5 years and
finally decided to if these fit my boat.

Can someone decipher these for two me?

#1
(Printed on gear inside the prop)
Michigan Wheel
033072
14.25R15
(Outside)
Rapture

14.25" diameter, 15" pitch stainless standard rotation.

#2
(Printed on inside)
826074 B 24
(Outside)
Mercury Marine Tempest Plus
48-825864 23P

14 5/8" diameter 23" pitch stainless standard rotation.

Two radically different props. Assuming they physically fit on whatever
type of boat you have (I am assuming it's an I/O) each will have
totally different performance characteristics. You really need to
determine what size and pitch is currently on your boat and also confirm
that for your usage the engine is operating within it's specified RPM
range, particularly at wide open throttle. Generally, the 15" pitch
prop is going to allow higher RPM at WOT. The 23 " pitch will produce a
lower WOT. The ideal pitch is when your engine runs at the maximum
recommended RPM at WOT. It also depends somewhat on the loading of
your boat ... how many people are typically on it... how big is it, etc.

Again, (assuming they physically fit) you really need to determine what
prop you currently are running and if it produces the recommended engine
RPM range for your usage.
From there you can predict somewhat if either of these props will hurt
or improve performance.