Straight as she goes!!

Discussion in 'Powerboats' started by grady, Jan 21, 2020.

  1. grady
    Joined: Oct 2006
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    Location: Scituate, Ma

    grady Novice

    Hey BlueBell, I'd describe it as a deliberate steady heading correction to maintain course.

    Mostly happens on plane at cruise.

    Thank you for your response

    TonyG
     
  2. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    You're not making it clear enough about the steering correction. A continuous "deliberate and steady" application of the wheel would soon end "hard over". There may be something wrong with the hydraulic steering by the sounds of it.
     
  3. Barry
    Joined: Mar 2002
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    Barry Senior Member

    What type of steering is it, hydraulic? Power
    When you correct to a straight line, do you feel feedback in the wheel?

    I had asked the questions are you level at rest and underway as it is almost impossible to have a boat that is perfectly balanced. Food, groceries, different weights of passengers, different water
    levels in the fresh, black water and fuel tanks if there are any on board, or even equipment. While boat manufacturers would strive to keep even the internal structures weight symmetrical but it is unlikely that this would even be 100%

    We used to own a 40 foot c/w twin I/O's with counter rotating props which weighed in slightly north of 30,000 pounds wet. On those rare mirror ocean days, (as our one way trip was 70 miles to
    the good fishing areas) I would trim the drives and tabs to optimum to save fuel. Hydraulic power steering, 23 knot cruise.
    All it would take is a 130 pound passenger to move from one side of the boat to the other and the boat would lose its straight direction. Normally, I would adjust the tabs and the wheel to and it would
    correct. Ie tabs to lift the low side, and the wheel to also deal with the additional drag caused by the slightly downward tab.


    So what I am saying is that any boat (as you will only have an instantaneous moment when the weight is balanced) will require a slight change either in steering or trim tabs usually both
    to make the boat go perfectly in a straight line.

    If your system is hydraulic and tight (non- leaking) when you are on step for your given unequal loading, you turn the rudders a bit to compensate and you should be able to take your hand off
    the wheel, but the rudders may be a little off a true parallel line with the keel.

    Other things that we found with our particular set up was moving in different tide induced current and even mild winds would make these small trim adjustment necessary
     
  4. grady
    Joined: Oct 2006
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    Location: Scituate, Ma

    grady Novice

    Ok...I apologize for not being clear.

    have you ever driven a car that pulled to the right due to a wheel alignment issue?? Kinda like that

    I have to steer to starboard to maintain course but once i'm back on course i can lessen the amount of correction and she will start to verve off course all over again.

    so if I look back at my wake...i'm in a lazy S pattern trying to steer straight.

    I never get to the point of hard over because as soon as i approach my heading i ease off the correction at the helm.

    I don't believe there is any leaks in the hydraulics only because it maintains a consistent pressure in the reservoir. but it could have other faults.

    It could very well be an imbalance in load from side to side. but she appears to sit level at rest and on plane.

    Thanks for your replies

    TonyG
     
  5. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    I think most have had the experience of a boat pulling to one side with mechanical steering, where you have to keep pressure on the wheel, but not turn it at all, to stay running straight, but with hydraulic steering, the feedback is not there, and once set, the boat will run straight, assuming waves and wind do not affect matters. It sounds like a problem in the hydraulics to me, like when you have air in a brake line.
     
  6. grady
    Joined: Oct 2006
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    grady Novice

    That's very interesting Mr. Eff, They did have a hard time bleeding the second station (in the tuna tower) after survey.
    something like 50 turns in one direction then 50 in they other...then do it again....I wasn't there. but heard it wasn't easy. Now wondering if that threw the main helm out of wack.

    Thank you

    TonyG
     
  7. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    I suspect a combination of causes in this case.
    Impossible to diagnose online.
    Perhaps after all the changes that have been made,
    it will miraculously track straight once back in the water.
    Or, we'll be able to get some sound, current feedback then.
     
  8. Barry
    Joined: Mar 2002
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    Barry Senior Member

    http://www.boatsteer.com/assets/Hynautic_1987.pdf
    Attached is a copy of a Hynautic owners manual. Just for reference.

    In this system when you turn the helm, the helm pump builds a bit of pressure and pushes a certain volume of fluid into one side of the double acting steering ram. At the same time
    the pilot operated check valve lets fluid from the non pressurized hose of the ram return to the helm pump reservoir. (not the fluid reservoir with the pressure guage)

    So assuming that the props are "precise", the rpm is "precise" the trim tabs are up and the boat still steers to port. The only other variables are an unsymmetrical hull out of the mold or
    a slight difference in loading. ( or some other type of unbalance drag on the hull)

    My own opinion is that unbalanced loading is the cause of the problem as it an easy assumption to make if all other items above are normal.

    An easy confirmation to this is to bring a crew of 600 pounds on board and when underway, tabs up, have them walk to each side of the boat holding the steering wheel still.

    If the boat changes direction due to weight change, then this is probably the cause for THE VEERING

    Now as most boats will have this issue to some extent what is the response. The natural response is then just to turn the wheel an 1/8 of a turn or some other proportion and the
    course becomes straight.

    If you make this small adjustment, get the boat on course, the rudders are in a slightly non parallel relationship to the keel to keep the heading , and you should not have to adjust the wheel again. But from what I understand that over time, the boat begins to head to port again, requiring another correction. Which means then the rudders have gone back to a parallel to the keel
    orientation as the water pressure acting on the rudders will just push them parallel.

    So going back to the first sentence. You turn the wheel, pump a bit more fluid into one side of the cylinder. IF the check valves, spool (shuttle) are perfectly non-leaking, you should not
    have to make another adjustment to the wheel. BUT it appears that you have to. Therefore it is likely that the check valves are leaking back into the system, the pressure bleeds of the
    high pressure side of the cylinder, the rudders orient themselves to parallel to the keel and you start the process all over again.

    So a check on this is quite simple if the rudder shafts are somewhat exposed.
    Run the boat and get the boat going in your intended direction, power down, don't turn the wheel. Lift the hatch, clamp say a rod or stick or anything horizontally to the rudder shaft record its position to a point in the boat, power up again, when the boat begins to veer, shut down again, don't turn the wheel. Lift the hatch, if and check that the rod is in the same position. I suspect that it is not. I think, as did others, that somewhere in your system one of the hydraulic components is bleeding back to the helm pump and letting the rudders return to parallel. (an error in my wording the first time)

    The rod that I make a reference to would be clamped horizontal looking from the top down so you can magnify the amount of rudder turn for an easy visual.

    There is a You Tube Video, found perhaps by googling, Hynautic Steering Pump Rebuild that shows many of the components
     
    Last edited: Jan 26, 2020
  9. grady
    Joined: Oct 2006
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    Location: Scituate, Ma

    grady Novice

    Thank you for the responses....

    Lots to think about, I promise to give feedback once I either find and correct the cause.

    or symptoms cease.

    The one major challenge is there a lot of changes being made. so figuring out what the solution is might be akin to magic.

    had plans to upgrade steering components ( not immediately be eventually). hoping I can chase this demon before I do that or I may never Know.

    I'll try to document the sequence in which actions are taken and the resulting reaction that occurs.

    Thank so much

    TonyG
     
  10. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    TonyG,
    If you've lived with this for 8 years,
    and haven't been able to diagnose or fix it,
    then I would consider selling the boat.
    When is it back in the water?
     

  11. grady
    Joined: Oct 2006
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    Location: Scituate, Ma

    grady Novice

    Oh be still,.......lol

    No, not going to be selling her any time soon.
    Yes it has been a constant in our lives but not a deal breaker. we love the boat, and would love her to be perfect but we can't afford perfect.
    I haven't be chasing this particular quirk with neither time nor money. Although I have given it consideration whilst doing other tasks.
    She is hitting the water this up coming season.....with plenty left to do. But need to shake her down after rebuilds and system up grades.
    My thoughts have been to try and go through each and every system and correct things as they arise. One of these things will straighten her out....lol

    Thank you

    TonyG
     
    Last edited: Jan 28, 2020
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