Prop School Part 8: Propeller Finishes

The “finish” on a high-performance propeller refers to how the raw propeller casting is transformed into a ready-to-use propeller. The finish description can be confusing as different propeller shops and manufacturers apply them differently; some shops offer “blue printing” or “lab finishing” with the promise of increasing speed.

Mercury Marine produces a broad selection of Standard Finish propellers that deliver outstanding performance for recreational boating. To serve high-performance and racing customers, Mercury Racing offers its 20 propeller lines in two finish levels: Pro Finish and Lab Finish. The most popular Mercury Racing propeller models, the Bravo I and Revolution 4, are offered in both Pro and Lab Finishes. The Bravo I FS, LT, XS, XC, and Revolution 4 XP are all Pro Finish propellers.

Mercury Racing Rev 4 XP Pro Finish

Mercury Racing Pro Finish propellers retain the durability of a Standard Finish prop and the corrosion resistance of a highly polished surface while offering the benefit of a hand-finishing process. Mercury Racing propeller artisans start with a raw stainless steel propeller casting and finish and fine tune the propeller by hand. The end result is a blue-printed propeller that has perfectly matching cup heights across every blade and a custom blade thickness profile. The propeller is perfectly balanced, there will be consistency in RPM when running on a multi-engine setup, and in most applications the Pro Finish propeller will deliver higher top-end speed than a Standard Finish propeller. In most applications switching from a Standard to Pro Finish propeller will permit stepping up one inch of pitch due to the ability of the Pro Finish to generate higher RPM. The opportunity to run a propeller with more pitch can produce a 2- to 5-mph increase in top end-speed – simply from bolting on the propeller.

Mercury Racing Lab Finish Sterndrive CNC Cleaver

Mercury Racing Lab Finish propellers follow a similar journey but are taken to the next level with additional blade thinning, which creates a sharper wedge that cuts through the water with less power-robbing drag and, once again, an increase in top-end RPM and a step up in pitch by about one inch with a corresponding gain in top speed, compared to a Pro Finish model. Mercury Racing Lab Finish props are especially effective on lighter-weight high-performance boats capable of running above 80 mph. Lab Finish props are durable but the ultra-crisp blade edges must be maintained to retain peak performance.

Mercury Racing offers a diverse line of propellers that are continually tested and improved in the most demanding environments. Mercury Racing backs its props with a one-year factory warranty, which also covers any and all damage done to the engine upon propeller failure.

The Bravo I FS has taken the bass, walleye, and multi species market by storm, in part because of the top end speed gains from its Pro Finish.

The only propeller not built exclusively by hand is the CNC Cleaver, which features our Lab Finish specifications for maximum top end speed.

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16 thoughts on “Prop School Part 8: Propeller Finishes”

    1. Rob,

      Best practice is to do a quick inspection of all edges after every time you run the boat. The leading edge, and trailing edge cups can last a long time on any prop depending on the type of water you are running through. Running through water with sand and silt in it will erode the cup heights and you will lose performace. Getting nicks in the leading edge will lead to blade failure. There are a lot of guys that get their props refreshed in the off season. If you have a labbed prop and need to send it to a shop for refreshing, I would be weary that they don’t thin the blades too much when making repairs.

      Nick

  1. Hi – I have a 2005 Hallett with a 525 and bravo XR ITS outdrive – would I be able to use the new CNC cleaver recently released?

    1. Jason,

      What are you currently seeing for top end speed? The cleaver is going to shine in 85+ mph applications.

      Nick

  2. I have and 2004 Outlaw Gambler with a new Pro xs 200 4 stroke . Im turning a 26 trophy 76 mph at 5960. I would like to try a Bravo fs not sure what pitch to try

    1. Ritchie,

      Do you have a jack plate? For optimal performance, consider the 26.5 pitch Bravo I FS and raising the engine about 3/4″. Your hole shot should greatly improve with the Bravo compared to the Trophy.

      Nick

        1. Ritchie,

          26.5 pitch in the Bravo FS is still my call. The diameter will reduce slip for better mid range efficiency as well.

          Nick

          1. i couldn’t turn it. lost 400 rpm and 3.5mph. A mechanic told me that I shouldn’t be running a small hub trophy on that motor. Is this fact or fiction? He also claimed if I prop wash that motor in the rough with that small hub will cause that motor to come apart.

          2. Ritchie,

            You couldn’t spin the Bravo? If you can spin a 26 Trophy, you should be able to spin the Bravo unless the Trophy has had aftermarket work making it thinner. As for your mechanic’s point, the Trophy is rated for 225 hp and should not cause any problems on your motor.

            Nick

  3. I have a 1999 formula SS with a 502 engine I believe it’s 430 Hp. I’m currently running a Rev 4 prop 23P that came with the boat it runs about 63 / 65 Mph range at 4900 rpm on a good day. The engine say’s 4600 / 5000 rpm is that the safe zone or max ? I have not owned the boat for very long but just recently had the prop polished but haven’t had time to put it back on yet. What do you think is that sound ok ?

    1. Randy,

      I wouldn’t change a thing, you have her dialed in! The Rev4 is typically the best prop for hole shot/ watersports on your setup as well.

      Nick

      1. Great is 5000 rpm safe ? The person I bought the boat from said 4800 / 5200 but I just want to make sure and not hurt the engine. Also one more question please a prop shop told me that polishing the prop may hurt a little bit of performance is that true ? I thought most props came polished.:) Thx

        1. Randy,

          5000 is fine. He was probably giving you a range of 4800 to 5200. Yes almost all Mercury Racing props come polished.

          Nick

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