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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31 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

  4. Scott, I have a 34 Fountain CC with 400R’s . Currently running Rev 4s 19 pitch . Turning about 6700 rpm’s and 67 mph . would a 20 pitch Barvo 1 FS help me pick up 300 rpm and maybe a little speed.
    Have heard good things.
    Dave

  5. Nick,

    Currently running a 22 pitch Bravo 1 XS prop on a Recon 985 with 200 Optimax with the AV plate on the motor at 2″ – 2 1/8″ above the boat bottom. RPM at 5600 and top speed is 56.5 on GPS When on plane and at speed, AV plate is running just at or slightly above the surface of the water. Hole shot is awesome, but wouldn’t mind picking up a little more top end speed. Was wondering what would happen if I raised the motor one more hole — putting me at 2 3/4″ height or slightly above, and then went up to 23 pitch Bravo 1 XS. I’m thinking the added height would decrease drag and up RPMs thus allowing me to handle the higher pitch (which would then bring RPM back down), and the added pitch would allow more top end. However, I’m afraid raising motor futher may get the prop too much at the surface. Thoughts?

    1. Jason,

      Consider raising the engine up one hole with your current prop and we can see how your efficiency changes. I don’t think there is very much left on the table, it is dialed in pretty well. If you are able to touch the rev limiter after going up one hole and your speed increases, you can step up in pitch. If you don’t see speed increases, you should stay at your current height.

      Nick

  6. Hi, I have an inflatable boat of mt. 7.30 with av hull (pad) with a total weight of 2800 pounds including outboard, equipment, crew and petrol, with Verado 300 outboard, with gearcase XL (25) and gear ratio at 1:85 foot, mounted at third hole height with revolution propeller pitch 25, maximum speed reached 63 knots at 6200 rpm.
    I have replaced the outboard with a new Mercury V8 300r with 544hd gearcase, which propeller model and which pitch should I mount? Thanks.

    1. Massimiliano,

      If you have the same propeller, that would be an excellent place to start. Because you have more gear ratio to work with, you should see speed increases right off the bat. I would start one hole higher for engine height.

      Nick

  7. I have a 2020 Ranger 621 with a Mercury 400 and no jack plate. Bravo 1 22 pitch with full tank and 2 people I’m getting 56 mph at 6050 rpm. Mid range is great at 4500 going 42.5 mph. I tried a Bravo 4 blade with 21 pitch and gained rpms to 6300 but lost midrange and only 55 mph. Any suggestions? Can a 400 Verado be upgraded to the 400R? Thx

    1. Dan,

      The 400 Verado and 400R are essentially the same engine, but the 400R spins 200 more RPM. It is a hard setup to dial for peak RPM. I’d recommend calling Brett at Bblades. He is testing a lab finish Bravo I FS with added tip cup on a boat that is almost identical to yours.

      Nick

  8. Hello, I have a 28 foot Magic Deckboat with a custom built 572 ci BBC motor that dyno’d at 775 HP, outdrive rebuilt to XR standards. The boat had a “labbed” 26 pitch Bravo 1 prop when I bought it years ago but we just noticed a 1″ crack in one of the blades. Used to see about 5,500 RPM and 72 MPH at WOT. Put a new stocker 26 pitch Bravo 1 on it and lost about 300-400 RPM and some top speed at WOT. Boat shop suggesting to try a 24 pitch Bravo 1 to see how it runs. I would really appreciate your suggestions as I would prefer a blade with more top speed at WOT (i.e. labbed 26 pitch Bravo 1???). Thank you!

    1. Richard,

      All of your math makes sense. The lab finish Bravo I should spin 300+ more RPM than the stock Bravo I. I would suggest going right back to a lab finish 26 pitch Bravo I. Your dealer can order straight from Mercury Racing.

      Nick

  9. Currently running 15 x 32 cleavers on a 22’ talon with twin 225’s. Looking at switching to 4 blade props to assist with cavitation getting onto plane. What would be your suggestion for profile & pitch?

    1. Jordyn,

      Our replacement for the 3 blade cleavers is the Bravo I OC. They are 14.50 diameter 4 blade, short tube, lab finished, with extra tip cup and eight vent holes. They really work well on twin engine two stroke cats right out of the box. Stick with the same pitch.

      Nick

  10. I have a 2008 Crestliner 1650 Sport Angler with a 2017 Mercury 115 4s with the AV plate on the motor at 2″ above the boat bottom. Apollo 19 pitch with full tank and 1 people I’m getting 49 mph at 5730 rpm. Mid range with 2 people at 3185 rpm going 24.3 mph. I think about Spitfire XP Pro Finish – can I improve the mid range? Top speed? What pitch do i need?

    1. Konstantin,

      Apologies for the late response. Your prop is hooked up so well I wouldn’t change a thing!

      Nick

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