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rudders for 4788-gctid374041

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  • rudders for 4788-gctid374041

    Has anyone replaced the rudders on a 4788 with the larger spade rudders? I just re-powered my 1996 4788 with re-manufactured Cummings 370's and need new rudders! I took older 315's out

  • #2
    "Has anyone replaced the rudders on a 4788 with the larger spade rudders?"

    I did not know there was a larger rudder for the 4788.

    Are the old ones beyond repair for some reason?
    Northport NY


    • #3
      the rudders on the 49 meridian were bigger,,i don't know when the change was made..why not call the manufacturer,,,,marine hardware in redmond washington at 206-883-0651..
      84-38,,86-38,,89-45,,97-47,,99-47,,01-47,,05-540 meridian,, 04-411 meridian and 11 others,, all gone ,,now 04 -490 ,,sidney,,vancouver island.


      • #4
        Some guys take their rudders in to a propeller shop and have them increase the surface area -- I'm not sure of the cost and which shops specialize in it. Might be worth looking into. Good luck. Rick
        2002, 3788


        • #5
          When i pirchased my 3988 the rudders had alot of corrosion after one season i purchased new ones from marine hardware. The previous rudders also had poor handling characteristics at slow speeds like in the marina.

          Marine hardware suggested i install the large rudders the put on the 4788. Refered to as barn door rudders. After the install of the new rudders slow speed handling improved greatly and I noticed no negative effects at any speed. Slow speed steering in the wind was a much better experience
          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


          • #6
            The OEM recommended a larger High speed spade rudder> Had several testimonials from 4788 owners raving about the increase in slow speed performance in quartering sea conditions. I ordered a set for $1279 us and it will take 3-4 weeks. My old rudder posts were badly corroded above the packing gland nut> I suspect a bonding wire that was off and a bad electrolysis issue at my old marina. Thanks for all the help! I have recent hands on experience with a cummings 315 to 370 re-power if any one needs any help.


            • #7
              Install 5" zincs on the rudders, also, when bonding the rudders you must bond the rudder post/shaft, not just the packing gland.
              Pat says: DO-IT-RIGHT THE FIRST TIME!

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


              • #8
                I don't understand why the engineers would put these silly little rudders on in the first place. Is there a good reason? do big rudders cause poor slow speed twin engine manouvres? do big rudders cause dangerous swerves at speed ? They seem counter intuitive. Perhaps a marine engineer can help