Propping F23 Donzi WA

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  • Propping F23 Donzi WA

    Hi Ken, in need of your wizdom. I've got a 1990 23 foot donzi walk around with a 2016 225hp verado with a 1.85 gear ratio leg with a Simon 300hp reflash on a factory bracket. If your not familiar with this hull its basically a 23 foot Grady gulfstream. 9 foot 4 inch beam. Boat is bottom painted and has a 15hp pro kicker. Holds 115 gallons of fuel. Motor height mounted all the way up. Full hard top and canvas, all testing was done in crappy conditions with 1.5 foot chop. Probably sitting around 6500lbs with fuel and gear. So far I've tested 3 props and haven't been happy with any of them. Engine height looked great on all 3 props tested. Here are the results

    Stiletto advantage II 17p
    28mph cruise @ 5300rpm - 17.5gph
    35mph WOT @ 6000rpm

    enertia 15p
    27.5mph cruise @ 4650rpm - 12.8gph
    38mph WOT @ 6000rpm
    minimum plane speed 21mph

    mirage plus 17p
    30mph cruise @ 4500rpm - 12 3gph
    40mph WOT @ 5550rpm
    22mph minimum plane speed

    from the slip numbers that I got I'm thinking I need a 4 blade or larger diameter prop? The stilleto just sucked on this hull so let's forget that. The enertia had great hole shot and the mirage had terrible holeshot. The mirage felt better at cruise and had better fuel burn and cruised at a higher speed. I'm looking for a better minimum plane speed, good hole shot, rough water handling and if I could see an improvement in fuel burn at cruise that would be great too. Overall I guess what I'm after is better slip % for more efficiency. Top speed isn't really a big concern. I can get cost plus 10% pricing on mercury props locally so I was thinking a rev4 but I have seen your previous findings that the rev4 in 15p sucks. With the 6000rpm we got with the 15p enertia I doubt a 17p rev4 is in the cards. What's your guess in my scenario? 14p mirage plus would be great I'm thinking but they don't make it and I don't have enough motor to spin a enertia eco from my results. I've ran out of props to borrow so next one will be a purchase so hoping we can nail it. Any advise will be appreciated.

    cheers.
    Last edited by DavieJonesRevenge; 04-22-2018, 10:13 AM.

  • #2
    How are you trimming the motor at speed, can you trim up much without porpoising? what happens if you trim higher?
    Where are you putting your tabs when you run it for these test?

    What hole is the motor mounted in? have you looked at the motor in the water flow while your running at cruise?
    If not, look at this thread with pictures and video to see what to look for. https://www.bandofboaters.com/forum/...gs-to-look-for

    From your numbers so far, it seemed to like the Mirage Plus, I'd just try a 15 pitch. for the next one.
    But let me know about motor trim, tabs, and engine height first.

    Ken Reeves
    [email protected]
    941-735-5808

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    • #3
      Thanks for getting back to me. Here is a pic of motor height at cruise. It's as high as I can mount it so that would be the bottom holes. For the testing we are running trim tabs all the way in so unused, and i haven't been looking at the trim gauge but to set the trim we have been trimming out a little at a time until we see a loss in speed then trimming back in slightly once we find that point. Not seeing any poirpoising at these trim amounts. I believe if trimming further out more than the speed would drop and the props would blow out. The enertia never blew out and the mirage did a very small amount occasionally.

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      • #4
        Here's another mounting height pic

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        • #5
          I feel like that boat should be quicker with 300 HP.

          Are you 100% sure your coils are good?
          Common issue with Verado's. if its down a coil, its about 10 MPH slower then it should be. but will run smooth as silk, no vibration, no computer codes, no warnings.

          I see a lot of guys claiming 50 with 250 HP, but most are CC's
          even still, your barely touching 40 with 300, just seems like its missing something.

          Ken Reeves
          [email protected]
          941-735-5808

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          • #6
            Hey Ken took your advice and ran the coil check. Got a bad one. Will get it fixed test some more and report back!
            Last edited by DavieJonesRevenge; 04-23-2018, 10:55 PM.

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            • #7
              Fingers crossed, let us know what happens.
              Hopefully it takes off and runs strong.

              Ken Reeves
              [email protected]
              941-735-5808

              Comment


              • #8
                Wow it’s amazing how KENTHEPROPGOD!!!! Can t-shoot this boat never seeing it hearing it or driving it and nailed it. WOW!!!

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                • #9
                  well now I'm curious how it ran after the coil ha ha.

                  Ken Reeves
                  [email protected]
                  941-735-5808

                  Comment


                  • #10
                    Hey Ken been a long time since I started this thread but I wanted to report back. Tried a rev4 17p and it ran at 6100rpm WOT at 44mph. 17% slip which was the best of the bunch that we tested so we went with it. As of recent I have not been happy with my fuel economy at cruise with the rev4. We spend all of our time on this boat fishing salt water out of Vancouver BC Canada and there is always some wind and some chop to contend with. I did all of my original prop tests on a local fresh water lake that was glass calm which I think was a mistake since this boat only runs in salt water with tides, currents,wind and chop. We carry quite the load of fishing tackle and traps when we go out so combined with the heavy load of gear and people and in salt water the 17p rev4 is only spinning 5700rpm at 37.5 mph which is out of the rpm range of the 300 verado and slipping 23%. I ordered a 15p mirage plus to try out. Really hoping that the 15.75 diameter prop will hook up better. Other than that I was thinking of getting the rev4 reworked into a 16p. Would you have any other suggestions or advice? Thanks.

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                    • #11
                      I have the FIRST, Powertech 16 pitch version of the Rev 4. I don't know what they are going to name it. Haven't even got it out of the box yet.
                      But its sitting here in my office waiting to be run on something.
                      Your boat sounds like a perfect candidate.
                      Call me if you want to run it.
                      FunkyMonkey (Marcus, at Powertech will be curious of the results as well)

                      Ken Reeves
                      [email protected]
                      941-735-5808

                      Comment


                      • #12
                        The other option would be to put a lot of cup into that Mirage Plus. They don't have much cup to start with, so they normally do very well with added cup, especially the 15 pitch.

                        Ken Reeves
                        [email protected]
                        941-735-5808

                        Comment


                        • #13
                          You the man Ken. Thanks for the speedy response. I should mention that my 300 verado is a counter rotating so I'd bet your 16p powertech is the wrong rotation for me. I'll probably give the mirage plus a test spin when it gets here and record some data first, then get it cupped and see what that does.

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                          • #14
                            yeah, its a RH darnit

                            Ken Reeves
                            [email protected]
                            941-735-5808

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                            • #15
                              Hey Ken curious what is your opinion on the LFS3 in the lower pitches? Been looking at it since I dont have enough motor to turn an enertia eco

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