Prop question

[ocuyler]

Guys,

This is a non-SeaCraft prop question. I have 2 sets of wheels for our Carver 32 aft cabin. It came with 3 blade bronze that need 3500 RPM's to get the boat cleanly on plane at 22 MPH with a WOT of 4750 RPM's with a light load. The 350 Crusaders spec 4000 min. WOT at full load and 4400 max. with a light load. So those are "off" by 300 - 350.

The second set, purchased from Michigan Wheel have 2" more pitch and produce 23 MPH at 3300 RPM for a clean planing with a WOT of 4400 with a light load. This sounds good in theory and is fine in light or no seas, but with the less torque, she is quick to fall off plane and/or struggles in a seaway pushing against the backs of waves.

The test Carver did on this hull/motor configuration determined 3200 RPM produced 23 MPH using 22 GPH (1.1 MPG) and a WOT of 4400 giving 32.5 MPH @ 41 GPH (.79 ouch).

I like the way she runs with the factory props at higher RPM's, and feel the motors like running with the higher torque. Both have 360 fresh water hours and are in perfect order. So, TWO QUESTIONS:

1. Could the tach's be off?

2. Does anyone feel running 3500 for hours has a downside?

Any input would be appreciated.