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  • Bayliner 4788 Stabilization

    After spending two solid weeks in a quartering beam sea doing the Baja Bash I have decided to bite the bullet and add stabilization to my 4788.

    The goal is to reduce the persistant roll that occurs in very moderate seas. It seems that even a sea you can barely notice can set up a very violent roll scenario in the 4788 hull.

    With that in mind, and realizing I am in Mexico here were my choices.

    1. I could add underhulls similar to what was marketed by North harbor Diesel. Owners report that these are fairly effective at a low cost.

    2. I could add paravanes to the boat. These would be very effective but would change the look of my boat dramatically and everyones opiniĆ³n not in a positive way. The cost of these is probably in the $20K range realizing skilled labor here is $35 an hour

    3. I could add active fin stabilizers. This is the near perfect solution The challenge with this is it is out of my price range at around $75K installed.

    4. I could add a gyro stabilizer by Seakeeper or similar. The problem with this is space, weight, and money. These things work great but are huge, heavy, and again I think I'd be close to $75K by the time I leave the boatyard.

    5. The last choice and the one I am implementing is to add something called bilge keels or rolling chocks to the hull. Think of these as two keels that stick out of the hull at a 45 degree angle maybe 10" and run the length of the boat from about the pilothouse to the stern.

    I have researched this extensively and for some hull forms these provide a dramatic reduction in the roll. I have also talked with someone that personally added these to his 4788 and was thrilled with the results. He described the 4788 hull as a beachball in the water. There is nothing to slow the roll except the little keel.

    Talking to him on the phone a couple of weeks ago he told me the boat is a entirely different boat, with the tendancy to roll in a ever increasing angle from a small wave set to be entirely eliminated.

    I am scheduled for haulout on Monday at Baja Naval in Ensenada and the work is expected to take up to 4 weeks.

    Here are some photos I found of previous installations.



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    KEVIN SANDERS
    4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


    Where am I right now? https://maps.findmespot.com/s/218P#history/assets

  • #2
    Cost for option 5?
    1989 26' then 1994 32' now 2001 39'

    Comment


    • #3
      For the person that has installed these on the 4788 does he have any data/information on the following:
      - how does it affect efficiency at hull speed?
      - what is the affect to rpm at WOT with no other changes?
      - does he know the resultant fuel burn change (if any) at higher rpm cruising speeds?

      We have a number of non Bayliner boats with these bilge keels near us but they are all shorter hull lengths, lesser beams and have always had them.
      Northport NY

      Comment


      • #4
        Originally posted by Uncle_Bob
        Cost for option 5?
        With the current price for resin and fiberglass Baja Naval is estimating $12K including haulout and re-launch.
        They charge $35 an hour for labor, and the estimate is just that. They estimate, and then bill actual.

        KEVIN SANDERS
        4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


        Where am I right now? https://maps.findmespot.com/s/218P#history/assets

        Comment


        • #5
          Originally posted by smitty477
          For the person that has installed these on the 4788 does he have any data/information on the following:
          - how does it affect efficiency at hull speed?
          - what is the affect to rpm at WOT with no other changes?
          - does he know the resultant fuel burn change (if any) at higher rpm cruising speeds?


          We have a number of non Bayliner boats with these bilge keels near us but they are all shorter hull lengths, lesser beams and have always had them.
          Ron, I asked those same questions.

          He did not run a WOT test which I will have to do. He does not like to run the boat up on plane.
          He reported no discernible change in displacement speeds vs RPM.
          Major fuel economy changes were not noticed either, but I get the impression that he does not keep strict logs.

          These are of course questions I will need to answer.

          The big thing we need to do is not to have them too far foreward, where the hull starts to narrow.
          They will work best when installed parallel to the water flows on the hull


          KEVIN SANDERS
          4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


          Where am I right now? https://maps.findmespot.com/s/218P#history/assets

          Comment


          • #6
            I have no data on these - so my opinions are useless.
            Any running surface area will affect the efficiency ...but I have no way to judge the impacts.
            Northport NY

            Comment


            • #7
              Originally posted by smitty477
              I have no data on these - so my opinions are useless.
              Any running surface area will affect the efficiency ...but I have no way to judge the impacts.
              you are correct.

              Everything produces drag.

              Paravanes for example result in approx 1/2 kt reduction in speed on a 50' boat

              KEVIN SANDERS
              4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


              Where am I right now? https://maps.findmespot.com/s/218P#history/assets

              Comment


              • #8
                Love to hear your updates, When extened our boat we from round to hard chines (like under hull idea) it reduced the roll and since we extend the hull 5' we pickup bounce, speed and efficiency. But she still has an uncomfortable roll as you noted, just less then before ...hope this is huge improvement, as I would love to follow and go Baja Naval if your reports are positive.
                Mark
                USCG OUPV
                1990 4588
                Carlsbad, CA

                Comment


                • #9
                  Will this type of stabilization have a negative effect with strong following seas. Will it increase the possibility of broaching when crossing bars (Columbia River bar, Westport bar)? The hull extension (swim step box) on my 3988 appears to make the boat more squirrelly in following seas.

                  Comment


                  • Destiny_4588
                    Destiny_4588 commented
                    Editing a comment
                    Our hull extension does not intact I think the boat handles better in following seas then in past

                • #10
                  Originally posted by gfrodel
                  Will this type of stabilization have a negative effect with strong following seas. Will it increase the possibility of broaching when crossing bars (Columbia River bar, Westport bar)? The hull extension (swim step box) on my 3988 appears to make the boat more squirrelly in following seas.
                  I do not know.

                  Many trawlers have large keels. Do the large keels make the boat act differently???

                  It is a great question, and one I do not have an answer for.

                  KEVIN SANDERS
                  4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


                  Where am I right now? https://maps.findmespot.com/s/218P#history/assets

                  Comment


                  • #11
                    Here is an excellent article on bilge keels or rolling chocks.




                    KEVIN SANDERS
                    4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


                    Where am I right now? https://maps.findmespot.com/s/218P#history/assets

                    Comment


                    • #12
                      Wasn't that long ago a member posted info on his upgrades to a 3288 including rolling chocks. Lots of other upgrades that are quite impressive. Good luck with the upgrade.

                      LH Boat Info Be sure to explore the "Other Sites" page.


                      James
                      1989 Bayliner 3888, 175 Hinos,
                      Hurth 630's Onan 8kw MDKD
                      Lowrance Electronics!
                      Boating on Georgian Bay & the North Channel
                      Completed the Great Loop 07/25/19
                      AGLCA #8340
                      MTOA# 7469

                      Comment


                      • #13
                        Kevin;

                        If I recall correctly, last year you had planned to have bilge keels installed in Canada, then changed your mind due to insurance survey concerns. Have you found a way to alleviate this concern?

                        MV Dreams - 1999 3988
                        330 Cummins
                        Wrangell, AK
                        OUPV

                        Comment


                        • #14
                          Originally posted by Renilyab
                          Kevin;

                          If I recall correctly, last year you had planned to have bilge keels installed in Canada, then changed your mind due to insurance survey concerns. Have you found a way to alleviate this concern?
                          Yes, I had my survey last year

                          The challenge I faced last year was a fresh, untested set of bilge keels on the boat and potential questions the surveyor might ask.
                          I was on my way to Mexico, and needed a survey and a new insurer to cover my boat in Mexico.
                          Perhaps they would want a engineering study before completing the survey since the keels would be brand new???
                          Perhaps this would delay my trip while waiting for these questions to be answered?

                          This year is different...
                          I have a insurance policy for Mexico already.
                          By the next time I need a survey the bilge keels will just be part of the boat, having been there for years.

                          KEVIN SANDERS
                          4788 DOS PECES - SEWARD ALASKA - LA PAZ BCS MEXICO


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


                          Where am I right now? https://maps.findmespot.com/s/218P#history/assets

                          Comment


                          • #15
                            Kevin, i would like be interested on the progress. do they have print as to the mounting Specs for the mounting?
                            Charles Matthews
                            Camelot 1998 4788
                            Old Saybrook, CT

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