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Power Steering Issues W/ Ocean 57SF

Discussion in 'Ocean Yacht' started by Tom Childs, Jun 27, 2023.

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  1. Tom Childs, Jun 27, 2023
    #1
    Tom Childs

    Tom Childs New Member

    Joined:
    Apr 15, 2016
    Messages:
    17
    Location:
    Virginia Beach, Virginia
    The steering on my Ocean 57 SF has a dead spot that is about 1/2 of a turn and when get it over the hump at the end of the dead spot the boat oversteers to correct. I best describe it as "you turn, nothing happens, you count to 8 and then she turns. Very hard to go straight. The steering system is Hynautic 3 line with:
    1. Single hynautic helm pump
    2. Autopilot
    3. Hynautic hydraulic reservoir
    4. Hydraulic filter
    5. Hydraulic cooler
    6. Power steering pump integrated into engine
    7. Power assist ram
    Here is the story:
    1. A year ago noticed the steering ram was leaking out the seal and saw that rod was pitted.
    2. As couldn't find new, replaced ram with a rebuilt one
    3. Steering worked as normal for ~ 6 months
    4. Steering started the above described behavior
    5. Replaced the helm pump, bled system... no change
    6. Removed the Ram and sent it back. Tested under his pressure and found a small leak in the power assist control box. Repaired. Reinstalled, bled system... no change
    Other observations:
    1. The autopilot can steer and go straight for a while but will "loose rudder" and need to be reset - after which she'd steer straight until the next time it "lost rudder"
    2. The last time I had her out and steering manually you could hear the help pump moaning.
    3. With the engines off I can steer the rudders to starboard but once hit the limit, I can't steer them back
    Next steps:
    1. Trying to get a friend with a power bleeder over to re-bleed the entire system.
    2. Rebuilding the original help pump and will replace the new one.
    3. ANY GOOD SUGGESTION FROM THIS FORUM - - HELP PLEASE
  2. Capt Ralph, Jun 27, 2023
    #2
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
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    Messages:
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    Location:
    Satsuma, FL
    Hopefully only one engine has the power steering pump.

    A dead spot at the help pump helps me think an issue with one of its internal pistons. But as we know, hydraulic wheel pumps don't keep center for long with an AP in the works So a bad spot in the wheel will move, not always when going straight.

    Moving the rudders hard over and not able to reverse directions, if not a mechanical bind, helps me think the assist/check valves are sticking.

    The tension sense / assist valve & assist cylinder assembly is my first target thru all of this.

    We did have similar issues with a later Hatt 65 PS system, big ugly dual cylinder gizmo never would settle down. Ended up removing all of the PS junk and keeping a manual single ram setup.
    Wow, What a dream to drive. AP drove a perfect straight line for its first time.

    "The autopilot can steer and go straight for a while but will "loose rudder" and need to be reset - after which she'd steer straight until the next time it "lost rudder""
    This is a separate issue, Rudder feedback problem, What model AP and rudder feedback unit in use?
    Last edited: Jun 27, 2023
  3. YachtForums, Jun 27, 2023
    #3
    YachtForums

    YachtForums Administrator

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    Messages:
    20,381
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    Love when a member details their equipment, steps and observations as a preface to a question. Saves time when our senior members are trying to diagnose. Hope you find some wisdom here Tom!
    Capt Ralph likes this.
  4. Tom Childs, Jun 27, 2023
    #4
    Tom Childs

    Tom Childs New Member

    Joined:
    Apr 15, 2016
    Messages:
    17
    Location:
    Virginia Beach, Virginia
    Thanks Captain Ralph!

    Just one of the odd things is that the helm pump is new with no change after installing so odd if the old pump had a piston issue and the new one did too. But, am rebuilding old one and we'll see if that makes difference??????

    If you watch it do this behaviors the assist cylinder is jumping like crazy. Why we sent it back to be tested. Anything else we can do to test/narrow down the culprit? - - besides replace all the PS junk? :)

    I am still suspicious that the autopilot losses the rudder do to it not being able to control the rudders through the "dead zone". I will get the model #s next time I'm at the boat.
  5. Capt Ralph, Jun 27, 2023
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    Location:
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    "Just one of the odd things is that the helm pump is new with no change after installing so odd if the old pump had a piston issue and the new one did too"
    Yes, I shot myself down in an edit a few minutes later in my post that probably knot the helm pump.
    "If you watch it do this behaviors the assist cylinder is jumping like crazy"
    Exactly what we observed. Yes, our Hynautic rep reported all was good in his test bay.
    "besides replace all the PS junk"
    We did aweigh with it, No PS junk. Went back to basics. just picked up a simple service valve and all else went to scrap. Really can not feel a difference while underway.
  6. Tom Childs, Jul 7, 2023
    #6
    Tom Childs

    Tom Childs New Member

    Joined:
    Apr 15, 2016
    Messages:
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    Location:
    Virginia Beach, Virginia
    Update -
    • Original cylinder was a Hynautic PSK-10 (can't find one anywhere)
    • New cylinder is a SeaStar HC5803 - (discontinued)
    • We found a Hynautic PSV-10 - Sequence Relief Valve in-line from the original power steering system. Thinking it may be competing with the relief valve built into the new cylinder we removed it.
    • Now we can steer the boat perfectly when the engines are off. Once we start them and the "power steering" takes over we still have the same dead spot.... as before.
    • Next attempt is to install a rebuilt servo cylinder in the HC5803 from Boat Steering Solutions
  7. Capt Ralph, Jul 7, 2023
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    YEP
    There is a hint in here.