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    4788 prop selection

    I am in the process of repropping. Boat engine and hull info in my signature. I guessed when we first got our boat and had a spare set of 24x24 Nakashimas repitched to 24x21. Fully loaded and engines tuned, I can get to 2950 rpm on a cool day, cool water, clean bottom and props. Ideally it would be great to get 3150 on hot day with average bottom. My goal is 3150 rpm under my tested conditions. I have pretty much settled on 24x20 nibral props as the best compromise.

    Here is my question.... what style and brand of prop? Michigan wheel has the Dynaquad for $2800 ea and DQX at $3400 ea. ZF has the KCA series with various mods for $2100 ea. There are several other manufacturers that have similar. What blade styles are you all running?

    btw, Kerr’s Propeller Handbook arrives tomorrow from Amazon. I’m trying to learn......
    2000 4788 w Cummins 370's, underhulls, swim step hull extension
    12' Rendova center console with 40HP Yamaha
    MV Kia Orana
    Currently Enjoying the PNW

    #2
    We are running a set of Nakashima props that we had cast to 24X21

    When I discussed re-pitching with “the prop shop” who have done allot of 4788’s they told me that re-pitching over about 2” was problematic, and that the re-pitching only affects the outer 2/3 of the blade area.



    Order online or come in and see Gary, John, Susan, Chris & Dianne for all your propeller & shafting needs. The Prop Shop has been serving boaters since 1979.

    KEVIN SANDERS
    4788 LISAS WAY - SEWARD ALASKA
    www.transferswitch4less.com

    Whats the weather like on our boat
    https://www.weatherlink.com/embeddab...59665f4e4/wide


    Where are we right now? https://maps.findmespot.com/s/36S4

    Comment


      #3
      Kevin,
      Thanks for the referral! I will contact them.

      I've learned that the Nakashima props are not available since joining up with Michigan Wheel. At least that is what a couple of shops have told me. Basically it is recommended that a high skew prop similar to the Nakashima be used.

      What props were on the when you first got your boat? What rpm were you able to get back then?

      Your new props are 24x21?? For some reason I thought you had gotten 24x22? At any rate, what rpm are you able to get now?
      2000 4788 w Cummins 370's, underhulls, swim step hull extension
      12' Rendova center console with 40HP Yamaha
      MV Kia Orana
      Currently Enjoying the PNW

      Comment


        #4
        Originally posted by Woodsea View Post
        Kevin,
        Thanks for the referral! I will contact them.

        I've learned that the Nakashima props are not available since joining up with Michigan Wheel. At least that is what a couple of shops have told me. Basically it is recommended that a high skew prop similar to the Nakashima be used.

        What props were on the when you first got your boat? What rpm were you able to get back then?

        Your new props are 24x21?? For some reason I thought you had gotten 24x22? At any rate, what rpm are you able to get now?
        I’ve got 330’s and am able to make 2850-2900 on a hot day fully loaded, just OK bottom

        I sed to have re-pitched 22’s and decided to just go with the 21’s which I had to have custom cast. About 2 month lead time.
        When I firse launched the boat I was able to get 2850 with a clean bottom fully loaded, medium temp day.

        KEVIN SANDERS
        4788 LISAS WAY - SEWARD ALASKA
        www.transferswitch4less.com

        Whats the weather like on our boat
        https://www.weatherlink.com/embeddab...59665f4e4/wide


        Where are we right now? https://maps.findmespot.com/s/36S4

        Comment


          #5
          Thanks Kevin! I learned today that Nakashima still builds and ships props to the US but are now sold under the Michigan name.

          Does anyone have experience with the Veem Conquest propeller built in Australia?
          2000 4788 w Cummins 370's, underhulls, swim step hull extension
          12' Rendova center console with 40HP Yamaha
          MV Kia Orana
          Currently Enjoying the PNW

          Comment


            #6
            I recently went through re-pitching my props and learned probably more than I cared to.

            When I bought my boat, it seemed to always lug a bit, but did ok... in time, the back would soot up pretty bad on long trips. After changing injectors and tweaking of other things, it still seemed to suffer from underperformance,..and still sooted. I decided to investigate my props, though there were supposedly pitched properly.

            Omega originally came with nakashima props, but I found they had been changed to traditional Michigan props by the time I bought her. The Michigan props had been pitched as the nakashima had been , which after digging into things more, are not equivalent when pitched the same. I was told by a couple of prop experts said a nakashima is not equivalent to a same pitched Michigan prop by a couple of inches of pitch. In my case, my 32x35 Michigan props were way over pitched and lugging my engines, as they were performing like they were swinging 32x37 nakashima props... oooph! I’m not sure how different the pitch is for a smaller prop, but I bet it’s pretty similar.

            I did find that nakashima props are still available, though through a fairly few companies. One company I found in Washington, was kruger and sons propeller. Www.krugerpropeller.com. I believe they are the only dealers in Washington for nakashima props.

            Another thing I would suggest is Spending $50 for a subscription to www.boatdiesel.com. They have a very helpful prop calcualtor. It takes into account your exact engines, Hull factors, transmissions, etc, to help dial in the propeller properties if you use th advance prop calculator. There are other things on that sight that are helpful,too, but th prop calculator was a good investment for me, I did that and found my calculations were pretty much spot on after I had my props done. A couple prop experts suggested a simpler way to figure the pitch,but the calculated pitch was pretty different. I’m glad I stuck its my guns and did the props as I calculate as if I had pitched the props to what they suggested I wouldn’t have been able to optimize my performance to exactly what I wanted...

            i hope this helps...

            ~BJ
            OMEGA
            5788
            BJ
            OMEGA
            5788

            Comment

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