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Bent shaft advise; B O A T (bust out another thousand) is taking effect.

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    Bent shaft advise; B O A T (bust out another thousand) is taking effect.

    History - I have owned this boat for 3 years now. During first test run I thought I felt vibration. Broker, marine surveyor & engine surveyor told me the vibration for this type of boat is normal. We don't use the boat much maybe 1 - 2 weekends a month. Each time we take it out, I feel the vibration. I dive the hull every 3 months for scrubbing and zinc replacement. I inspect the props, struts and rudders for any damage. I never find dings or any visible damage.

    Current day - I pulled the boat out for routine hull painting and decided to have the props trued & balanced. The shop measured the shafts for straightness and reported back that both shafts are beyond repair and require replacement.
    I received an email after closing on a Friday before xmas. Boatyard not to reopen until 12/26.
    The shop divided the 10' shaft into 10 sections (A-J) and showed the deviations of my shaft on a drawing.
    Port shaft readings = section A-E = .017-.002 section E-J = .002 -.001
    Starboard shaft readings = section A-E= .030 - .005 section E-J = .005-.007
    Prop shop wants $8,000 to replace both.

    This is my question - Do these numbers say the shafts need replacement OR continue running with vibration?
    Any input is appreciated. Thanks Van.

    #2
    Originally posted by scubadiver3988 View Post
    History - I have owned this boat for 3 years now. During first test run I thought I felt vibration. Broker, marine surveyor & engine surveyor told me the vibration for this type of boat is normal. We don't use the boat much maybe 1 - 2 weekends a month. Each time we take it out, I feel the vibration. I dive the hull every 3 months for scrubbing and zinc replacement. I inspect the props, struts and rudders for any damage. I never find dings or any visible damage.

    Current day - I pulled the boat out for routine hull painting and decided to have the props trued & balanced. The shop measured the shafts for straightness and reported back that both shafts are beyond repair and require replacement.
    I received an email after closing on a Friday before xmas. Boatyard not to reopen until 12/26.
    The shop divided the 10' shaft into 10 sections (A-J) and showed the deviations of my shaft on a drawing.
    Port shaft readings = section A-E = .017-.002 section E-J = .002 -.001
    Starboard shaft readings = section A-E= .030 - .005 section E-J = .005-.007
    Prop shop wants $8,000 to replace both.

    This is my question - Do these numbers say the shafts need replacement OR continue running with vibration?
    Any input is appreciated. Thanks Van.
    Ask if the shafts can be straightened. Also check the shaft to transmission flange alignment in the water if possible.
    Was it the prop shop that measured the shafts or a repair shop?
    I have seen shafts straightened by using a torch with a very fine tip to heat the necessary location and straighten the shaft.
    Pat says: DO-IT-RIGHT THE FIRST TIME!

    Bayliner 3870 "ALASKA33)
    Twin 350 GM power
    Located in Seward, AK
    Retired marine surveyor

    Comment


      #3
      First, https://m.youtube.com/watch?v=bOT4cSTJyqw
      There is a real danger to Turn Wright you tubes, he has a lot of them and he does some interesting stuff.

      second, https://m.youtube.com/watch?v=dNuSh8ZMKIo

      Third, iiwm, I'd get some other opinions. Like boat implied, there are more questions to be asked.
      P/C Pete
      Edmonds Yacht Club (Commodore 1993)
      1988 3818 "GLAUBEN”
      Hino EH700 175 Onan MDKD Genset
      1980 Encounter Sunbridge "Misty Blue" (Sold)
      MMSI 367770440
      1972 Chevrolet Nova Frame off Resto-mod in the garage
      Boating on the Salish Sea since 1948

      Comment


        #4
        I can only guess that the prop shop measured the shaft. No time to speak to anyone about this issue.

        Comment


          #5
          Thanks for the videos. Very enlightening.

          Comment


            #6
            Another thing to check or maybe just replace is /are the cutlass bearings. If you have been running on bent shafts there is a good chance they need replaced or maybe just do it while the shafts are out.

            $8k seems high to me. Im guessing you can buy the shafts for around $1500 each. (I paid $1200 for 2 shafts for my 32 including shipping) im guessing on your price for yours. Further more its not rocket science just some hard work. If you have the capability to do it yourself this would be a good project. I just removed the 2 shafts in my 34 foot in about 2 hours.

            i just paid around $100 each for the cutlass bearings 1 1/2 inch inside x 6 inch. While im at it im also installing dripless shaft seals those run $3-500 each. You could do all that and still be under half of $8k .

            i do understand not being able or not wanting to do it yourself but if capable its not a dificult job. Although not necessrily fun. Probably the most critical would be aligning the engines. If you worry about that pay someone for that part but that also isnt difficult once you understand the process.

            Trying to remember my 3988 ,if i remember right the couplers are pretty exposed and easy to get to. On my 3450 its a v-drive and they are under the engines kind of hard to work on. I replaced a shaft a prop a rudder and a strut on my 3988 and it took me way less than a entire day.

            The biggest issue is usually having problems getting the coupler off. If thats comes off easily then the rest is disassemble and reassemble a piece of cake.

            i purchased my shafts from this site. Over all i was happy with price and speed of delivery. Enter your specs and youll see how much they will cost.

            https://www.deepblueyachtsupply.com/...hoCRzwQAvD_BwE
            1989 Avanti 3450 Sunbridge
            twin 454's
            MV Mar-Y-Sol
            1979 Bayliner Conquest 3150 hardtop ocean express.
            Twin chevy 350's inboard
            Ben- Jamin
            spokane Washington

            Comment


            • scubadiver3988
              scubadiver3988 commented
              Editing a comment
              Shaft seals, strut bearings are being replaced. No cutlass bearing on this boat.

            #7
            Its probably a long shot, when you have a final cost, talk to your insurance company. I’ve only had one claim ever with the boat, on my dinghy, but was surprised when they paid out in full. Wasn’t even going to claim until a friend suggested it.
            1996 4087 Lazy Days
            2007 Walker Bay Genesis Lazy Mac
            2011 Porsche Cayman
            2010 Lexus IS 250C
            2008 Honda Ridgeline

            Comment


              #8
              Personally if you can confirm shafts are bent or not true I would replace as that vibration will result in other issue cutless bearing failure, coupler wear and even transmissions issues from wiping of shafts causing transmission to have fight the vibration/warp

              also I believe you have a performance improvement as result as well and avoiding other premature maintenance repairs to cutlass, shaft log, coupler and transmission
              Mark
              USCG OUPV
              1990 4588
              Carlsbad, CA

              Comment


                #9
                If you are out of the water you can set a dial indicator at the end od the shaft and see what the run-out is.
                Be sure the coupler is aligned between the shaft and transmission.
                Did they measure the shafts in the boat or out of the boat? Makes a big difference if the shaft coupler is not aligned while coupled..
                Pat says: DO-IT-RIGHT THE FIRST TIME!

                Bayliner 3870 "ALASKA33)
                Twin 350 GM power
                Located in Seward, AK
                Retired marine surveyor

                Comment


                • scubadiver3988
                  scubadiver3988 commented
                  Editing a comment
                  The shafts and the couplers were removed from the boat and measured and the prop shop.

                #10
                I'm with destiny. Check the entire system from the transmission back. I did a quick pricing of link that Yachtman gave and I can get a 65" one and a half inch top quality shaft for about $700. There's still the connection plate that adds a hundred, but it's less than I thought it would be.
                P/C Pete
                Edmonds Yacht Club (Commodore 1993)
                1988 3818 "GLAUBEN”
                Hino EH700 175 Onan MDKD Genset
                1980 Encounter Sunbridge "Misty Blue" (Sold)
                MMSI 367770440
                1972 Chevrolet Nova Frame off Resto-mod in the garage
                Boating on the Salish Sea since 1948

                Comment


                • scubadiver3988
                  scubadiver3988 commented
                  Editing a comment
                  My shafts are 126" x 2" solid stainless steel. One end is standard thread + taper for the prop end. The other is meteric thread and taper for the coupling.
                  I checked online and one shaft was $1,700 - $2,300

                #11
                allowable runout is 0.0008
                Be good, be happy, for tomorrow is promised to no man !

                1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                Manalapan N.J

                Comment


                  #12
                  Okay, this is kinda potayto patahto, but cutlass bearing is also known as a strut bearing.
                  P/C Pete
                  Edmonds Yacht Club (Commodore 1993)
                  1988 3818 "GLAUBEN”
                  Hino EH700 175 Onan MDKD Genset
                  1980 Encounter Sunbridge "Misty Blue" (Sold)
                  MMSI 367770440
                  1972 Chevrolet Nova Frame off Resto-mod in the garage
                  Boating on the Salish Sea since 1948

                  Comment


                    #13
                    Two summers ago we really struggled with a vibration after putting on new props. Found the port shaft was actually torque twisted. Not sure how you torq twist a 1 3/4 shaft but we put a new one on for 1200. 8000 grand seems incredibly high.
                    Guntar
                    1999 3988
                    Cummins 270s

                    Comment


                    • scubadiver3988
                      scubadiver3988 commented
                      Editing a comment
                      I'm agreeing with the hgh cost; just to be clear the $8k covers 2 shafts and labor to install both.

                    #14
                    Propeller depot online 1 1/2" x 10' shafts about $2100 pair plus shipping
                    Aqualoy A22 shafts


                    https://www.propellerdepot.com/
                    Pat says: DO-IT-RIGHT THE FIRST TIME!

                    Bayliner 3870 "ALASKA33)
                    Twin 350 GM power
                    Located in Seward, AK
                    Retired marine surveyor

                    Comment


                      #15
                      Seen Bravo shafts twisted.
                      Be good, be happy, for tomorrow is promised to no man !

                      1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                      '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                      Manalapan N.J

                      Comment

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