Robalo Cayman 226

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  • Robalo Cayman 226

    Have a Robalo Cayman 226 with a SHO 250.
    Hardtop, 5 batteries, “two rear & 3 head”, two chargers, electronic package, power pole, trim tabs, Bobs 6” jack plate, 72” Minn Kota,

    these are are the numbers I am getting. On my third Propeller. Motor all the way down. 3/4 tank of fuel and two people, no gear.

    What im trying to accomplish. Get my WOT as high as possible to be able to drop down to a 40 mph cruise with the best mpg I can. For running offshore.

    “First prop tried”
    PowerTech 4 blade
    OFS4 15.25 x 19
    50 MPH WOT @ 5000 RPM
    2.1 MPG
    40 mph @ 4200 RPM
    3.0 mpg

    “Second prop lost top end and cruise mpg & gain 300 rpm on wot”
    PowerTech 4 blade
    OFS4 15.25 X 17
    46 MPH WOT at 5300 RPM
    2.0 MPG
    40 mph @ 4600 RPM
    2.3 mpg

    “Current prop”
    Yamaha Saltwater Series II 3 blade
    15.25 x 19 SDS
    WOT 48 MPH @ 5700 RPM
    2.0 mpg
    40 mph @ 4300 RPM
    2.7 mpg
    Thinking I should get more top in then 48 mph.
    48 mph When not trying to break loose and cavitate on lite chop in upper rpm.

    The PowerTech 4 blade 19 seemed to not cavitate, hold better any position on jackplate and have best mpg at 40 mph. But not getting my WOT RPMs.

    Only 8 hours on motor.
    Last edited by Shoalkat; 03-09-2019, 11:33 PM.

  • #2
    You said, "motor all the way down"
    I would trim and jack each prop to the height and trim level where you get your best speed.
    So at wide open, trim it up, jack it up, as long as the speed is improving, thats good.
    At some point, if you go to high, or trim out too far, it will gain RPM but the speed will drop off, we won't count that RPM.
    just get the RPM where you find your best speed.

    I would have expected much better numbers from that 17 OFS4. that is a huge drop in economy at 40

    Ken Reeves
    [email protected]


    • #3
      Thank you Ken
      I will run back to the lake today. Only have this 3 blade 19 SDS right now. I found the last time I ran it with the 19 three blade, in a lite chop running 41 Mph, I would see at times the rpms increase to around 4800, like cavating, gaining rpms without speed. I did try running jack plate up and down.
      Actually saw no speed increase with little rpm increase on the PowerTech 19. I would say it felt good and held tight on the upper end. If it got the rpm up at wot. Would had been pleased. Cruise was great on mpg and 50 mph is fine with me. Looking at a bunch on prop test and size and motor. I would think I could get mid 50’s.
      My boat was purchased with no JP. I added a Bob’s 6”. Motor is on bottom hole and the cavitation plate sets 1 1/2” higher then where the motor was directly mounted to boat. It was mounted directly to boat in second hole.

      Right now with motor motor all the way down, I’m 1 1/4” from hull bottom.
      Question, does a Lowrance StructureScan 3D transducer in front of the motor affect the WOT speed? Really no where to put on stern of boat with the way key slot is and trim tabs.

      One pic has a F200 on boat. At 30 hours. I removed the F200 and added the sho. Pic to show trim tab via transducer location. The reason for upgrade. I like a boat the cruises 40-45 going offshore on calm days. I go out top, 40 miles with a little running here and there. My boat would top out at 41 mph. I would catch myself going from 28-30 mph cruise on up to 38-40. Getting 2 mpg. I have a 60 gallon tank, ideally I would be able to go about 120 miles on a tank running wide open at 40 mph. So I got a SHO thinking I could get a top speed around 55 and back it down to 40-45 and get better mileage. If I was cruising at 3.0 mpg. That’s 180 miles to a tank. Nothing else, a piece of mind. And I don’t have to hammer my motor cruising in and out going offshore.


      • #4
        PowerTech OFS4 19
        Top out at 50 mph and 5000 rpm
        40 mph and 3.0 gpm


        • #5
          PowerTech OFS4 17


          • #6
            Yamaha SW II 3RH 19

            Upgraded the radio, same boat.


            • #7
              Question Ken
              I see bulletins 14.5 x 21 3 blade props getting 55 mph and 6000 rpm. That prop is no longer available.
              Going 3 blade different prop then the SDS? Still have the non slip at high rpm.

              Thoughts on a
              14x21 Solas Titan HR 4 blade
              14.25 x 21 Powertech PTZ4, SFS4, PTC4
              ideal on a three blade?

              fixing to load up to head to lake.


              • #8
                If you want a bowlifting 3 blade similar to the Yamaha Pro Series, I'd try a Mercury Tempest Plus.
                I'd try a 19 pitch though.
                You would only get the RPM if you gain some top end speed.

                Cost $30 to try one.

                Ken Reeves
                [email protected]


                • #9
                  You let me use that 19 Tempest.
                  As we talk in text, it kept breaking loose about 4600 RPMs. Skating and walking. The bow lifting got it really upset.
                  40.6 mph at 4600 rpms.

                  I just tried a Powertech PTC3 14.25 x 21. Just because what the bulletins showed for my boat. Getting 46.5 at 5200 RPMs wot.

                  I heard art of a guy on a forum getting 55 at @5800 same boat and motor with a Revolution 4 x 19. I do not know if weight difference with added stuff.

                  What at is the difference on the Tempest Plus vs Rev 4.
                  Have one and what size would you suggest?


                  • #10
                    The Rev 4 is a 4 blade tempest with a little longer barrel.
                    Same blades.
                    Gives more traction and more sternlift though.

                    Ken Reeves
                    [email protected]


                    • #11
                      If I get a Rev 4. What is the best route on Hub kit. The flo torque II has the right washer. People talk about the Rubex hub. I have a sho 250. Seeing stuff about prop shaft seals cooking?
                      Ideal on this?
                      what kit or kits would I need? Ok to run the Rev 4 on the sho?

                      Rubex RBX 203 ?
                      Flo Torque II 835274Q1 ?

                      washer out of the flo torque II
                      Last edited by Shoalkat; 04-11-2019, 07:42 PM.


                      • #12
                        Rubex 203B

                        2010-2013 they used different prop shaft seals. 2014 they changed, and I have not had any issues since, other then a couple 42+ ft CC's which I think were just over propped.

                        Ken Reeves
                        [email protected]


                        • #13
                          I will be in the Keys in July. Don’t mind taking a day if your available and meet people to help. If so, what would this service cost be? I have tried two more props from a local friend and powertech . About at a lost or expecting to much. Being I repowered a 30 hour F200 motor to a 250 SHO, was hoping for more. Seems I should be trying to sling a 3 blade over these 4. Getting one to give me the top in but grip in the bay on plate???

                          The Tempest Plus was wicked feeling on WOT.

                          The Rev 4 x18
                          47 mph @ 5700
                          40 mph @ 4900 2.3 mpg
                          33 mph @ 4000

                          Went out with some friends. Had a OFX4 19 on the boat
                          added two people (four total) 60 pounds of ice and some extra gear. Disappointed in prop performance.
                          45 MPH wot at 5100
                          33 mph @ 4000
                          Last edited by Shoalkat; 04-28-2019, 07:33 PM.


                          • #14
                            Also you thoughts on a OFS3 x 18 or a Mercury Enertia ECO prop and what to expect?
                            The shipping fees and restocking and trips to the lake plus launch fees is getting rich and time consuming.
                            A wonderful example of a beautifully crafted run on sentence!!! Smile life’s great. If our only stress, is what freaking prop!


                            • #15
                              Weird that the Rev 4 was so bad on economy.
                              Just curious, because the 18 is a very new pitch offered. Was that a brand new (less then a year old) Revolution 4 stock 18 pitch?
                              or was it a 17 or 19 that someone had repitched to 18?
                              Were the vent holes open or shut?

                              OFS3 I would expect to be about like your Saltwater Series ran.
                              ECO, would be interesting.
                              You would need a 17 pitch with the ECO. hopefully you could still get enough RPM.

                              I send the test props out for 30 plus shipping if you want to try one, I just have to wait for my 17's to come back.

                              Ken Reeves
                              [email protected]