Propeller FYI

[mikesxpress]

This may aide some folks in propeller selection/modifications. I'm using my "trued" prop for my new V8. Robbie at Propeller Dynamics in Hopewell is my local choice for prop mods.

My repower from the Opti changed everything regarding props, PVS plugs, JP height and trim settings. I had to shelf the 25P Tempest and start over.

The 4.6L 250 Pro XS V8 is capable of 6200 rpms and that's where it needs to run. If you have both mph/rpms you can enter it into the Mercury prop slip calculator and see where your at now but the goal is to get as close to 6200 rpms as possible. As every boat/rigging is different, loads are different, atmospheric conditions can be different, so no one prop is good for every boat of the same model/year.

The "out of the box" Mercury props (and all others) are made to industry standards which is +/- 2 on pitch blade to blade. Reputable prop shop with computerized measuring equipment can validate what you have and true up all the blades to say a 23P Fury. The PVS holes on my props are all plugged. Experimented with the various sizes and my rig performs best with all holes plugged which eliminated any blow out on take off.

Look for shops that have one of these machines.
https://www.halepropeller.com/hale-mri

http://propscan.com

Now you have an actual baseline to work from to get your rpms to 6150-6200. The speed will be what it is. Need more bow lift? Increase the rake but realize that will in turn drop your rpms and speed.

I just went thru all this the past 10 months with my V8 repower on my Z21 Intracoastal using 3 blade
23 (summer) & 24 P (winter) Fury's. The box prop blades on the 23 ranged from 25.5 on one blade to 22 on the next blade. The 24 wasn't much better. After they were true pitched ($210 each to do that) I had them adjusted again to achieve my desired 6150 rpms and bow attitude. 23P speed came in at 71.5 with 75° air temp/64° water temp. Final prop configuration saved at the shop for any future repairs or replacements.

Or you can just hang a box wheel on, run it, and save a few bucks.

[Macsimus]

The box prop blades on the 23 ranged from 25.5 on one blade to 22 on the next blade. The 24 wasn't much better.

[mikesxpress]

Cal all box props are like that and most folks don't know it. The lab finished props included. Take a new one and have it scanned on an MRI.

[Macsimus]

Cal all box props are like that and most folks don't know it. The lab finished props included. Take a new one and have it scanned on an MRI.

Wow. I'm no prop whiz for sure, but I don't know how they can possibly call that an "industry standard". I wonder if my outboard was built with any of those same generous "tolerances".

[mikesxpress]

Just the propellers.