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2001 Horizon 76 - Sea Trial

Discussion in 'Horizon Yacht' started by TahoeJohn, Oct 8, 2020.

  1. Capt Ralph

    Capt Ralph Senior Member

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    The gyro is leaking or a fin is loose on it's shaft.
    New controls will not fix this.
  2. Pascal

    Pascal Senior Member

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    It should not need trim tab in calm conditions except to get up on plane faster. It sounds like stab issue to me. I would ask what did the fin indicator show but I think you mentioned the display had some issues.

    stabilizers are important to comfort. Worth checking with Naiad if the control system could be upgraded. If too costly then repair the existing system
  3. mapism

    mapism Senior Member

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    I really struggle to understand what in those seatrial results is bringing you to these conclusions.
    Capt J obiously doesn't know how those stabs work, and what he said about them being unable to correct an inherent list is plain wrong.
    Besides, let's assume he's right instead: why on earth they should be less effective at higher rpm/speed, when exactly the opposite is true for ANY fin stabilizer system?

    Now, I don't know what sort of malfunctioning is affecting that Naiad equipment, but pretty sure there is something wrong.
    Capt Ralph might well be right on the money envisaging either a leaking gyro or a loose fin.
    I would add to that also the possibility of fin actuator(s) leaking, when at higher speed the fins rotation encounter a higher resistance from the water flow, but this is all just guesswork.
    Bringing onboard someone with grey hairs and experience on that equipment is what you really need.

    Regardless, I wouldn't spend one cent for the Multisea II controller, because that is NOT a more modern system.
    It's just an electronic interface that allows a bit more tuning to a system which remains old and entirely electro-hydraulic.
    Which doesn't mean bad - far from it. In fact, it actually doesn't need any tuning at all, when it works as it should.
  4. Pascal

    Pascal Senior Member

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    Something I haven’t seen discussed is How do the stabs perform in normal operations, both at hull speed and at cruise ? Do they keep the boat from
    Rolling? Any abnormal behavior?

    even in calm conditions they could be tested using another boat wake.

    or did the seller’s captain left them off except during these tests which would be a sign they are not working correctly. Personally, the stabs are always active as soon as we leave the dock.
  5. TahoeJohn

    TahoeJohn Member

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    There was a guy from NCH Marine on-board and all he does is marine hydraulics. He believes that the stabilizers were working correctly. And I've seen the boat start to roll slowly when the fins are turned off underway. All indications are that they work as expected but the old system is incapable of accounting for this occasional heeling at higher speeds.

    So what would you recommend? Are new systems not still electro-hydraulic? I'm honestly asking the question as I have assumed that they are.
  6. TahoeJohn

    TahoeJohn Member

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    As I just now mentioned above, they appear to be working fine. For both sea trials, they were turned on while underway. They were intentionally turned off during this morning's first two runs (and pinned) in order to determine if they were doing anything to cause the heeling at high speeds.
  7. TahoeJohn

    TahoeJohn Member

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    According to the marine hydraulics guy onboard today, the gyro is part of what would be replaced in an upgrade to a MultiSea II system.

    If a fin is loose on its shaft, I would think that a diver should be able to verify this with the fins pinned from the inside. Am I thinking about this correctly?
  8. Pascal

    Pascal Senior Member

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    I don’t see how a loose fin would be able to deflect and cause a list at higher speed since the shaft is positioned in the forward section of the fin. The pressure on the section aft of the shaft is much higher than on the pressure on the smaller forward area, forcing the fin to be centered in the flow.

    Unlike when in reverse when the prop wash could force the fin hard over if hydraulic pressure was lost.
  9. Capt Ralph

    Capt Ralph Senior Member

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    Two divers pushing against a locked fin, can not generate the force of water flowing in or against it.
    Moving forward will center the fin, when the shaft is told to twist, it will, the fin may follow or not, when the shaft twists back, the fin may follow or not.
    Remember, it's still a tight fit, no key, then can slip and designed to do so (usually under even greater forces).
    At speed, the fin is pushed back into position by the passing water.

    But I am backing off of that idea and leaning here;

    But I just remembered a problem from my past, a leaking cylinder piston seal.

    The Cheoy Lee 58 owner tells us: All system would start up fine. Driving a straight line required attention and sometimes the boat just felt funny.
    If checking things out, the first thing to do was slow down, check everything.
    Stabilizer was cycled, AP was cycled, Props were cleared, bilges checked, then give it the gas and all seemed well and sometimes for many more hours.
    The owner stated it was the AP and preferred then on to drive by hand.

    The needles were in the wheelhouse, none on the fly-bridge.
    The owner and family were always on the bridge and nobody cared a bit of the lower small bench seat below.
    The seat was usually covered in provisions and junk anyway.

    Later on a test ride, our associate was at the wheel house watching over the full inventory of pressure and temp gauges for everything, including the needles.
    He reported never before had observed the position display needles moving differently and in strange segments of the gauge range.
    He went to the engine room and noted the servos were not centered on a smooth day and hardly moved when the boat did roll.
    From this was more confused.

    After that we "T"ed in pressure gauges and found bad cylinders.

    New cylinders and adapter kits (obsolete rod ends) installed and all was well after.

    I am not a Naiad heavy (just fortunate to have worked on a few successfully); I'm convinced this boat has a problem.
    Another more senior member has said the same thing.
    Still another senior member says all o k.
    Jury still out on the rest.

    But it's your money.
    Your going to be the entertainer with a sky lounge full of people standing sideways on a smooth day.
    Have it fixed by an old grey haired, real tech.
    A hose guy just knows the hoses are not leaking.
    Throwing a fancy operator panel and reservoir top end at it ($30k+) may still not fix it.


    Captain Ralph Crapps
    Marine Solutions & Associates Inc.
    Last edited: Oct 13, 2020
  10. TahoeJohn

    TahoeJohn Member

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    Thank you, Ralph. I'm realizing that I'm not providing this forum all the information. I'll do so now because there is a lot of attention on the stabilizer system, and likely for good reason. I'm not trying to argue your point -- just trying to provide the experts here with all the data I have.

    This is what was done in February of this year (Cable Marine):

    REMOVE PORT STABILIZER ACTUATOR, LOWER STIFFENER AND HULL BLOCK, ETC.

    FURNISH AND INSTALL NEW STIFFENER, HULL BLOCK, ADD FIBERGLASS, REINSTALL UNIT AND PROVE.

    REPLACE STARBOARD STABILIZER SHAFT SEALS.

    REPLACE PORT STABILIZER ACTUATOR CYLINDER.

    TROUBLESHOOT / REPAIR / TEST STABILIZER ELECTRICAL SYSTEM

    All that to the tune of $36,652. That's not to say everything's fine, it's just to say that a lot of work has been done previously.

    And then about 6 weeks ago, the starboard actuator valve was replaced.
  11. Pascal

    Pascal Senior Member

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    That seems to be more than service or routine repair. Why did they have to replace the stiffener, hull block and do some glass work? These are tell tale signs of having taken a hit.
  12. Capt Ralph

    Capt Ralph Senior Member

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    Agreed.

    Doesn't explain the list issue. Unless fins were not installed correctly.

    Is the list issue new or been happening before this?

    I have good faith in THE Cable yard but everybody has a bad day.

    However, This could be where the cylinder piston seals got blown or other fluid parts stressed. Not just a backing block.
    Last edited: Oct 13, 2020
  13. DOCKMASTER

    DOCKMASTER Senior Member

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    I don't have any suggestions as my stabilizer experience is limited to giant fins on big ships but I have been reading this with interest. It does seem there is at least one vital piece of information missing that I do not see anywhere in the thread. When you say it heels to Port, how much are we talking here? A degree or two or more than that? Does the list to port continue to increase until tab is applied to correct? Or does it go over a certain amount and then stay there until tab is applied?
  14. DOCKMASTER

    DOCKMASTER Senior Member

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    And when you did runs #3 and #4 was there any beam wind to speak of?
  15. TahoeJohn

    TahoeJohn Member

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    Here's what I have so far on that, from an inspection made by the seller before placing the boat on the market:
    Screenshot 2020-10-13 153945.png

    In case it's too small to read, item 1 is: "Some delamination was noted on the port stabilizer foundation in the engine room. The stabilizer should be removed to allow for additional investigation. This area may require grinding of delaminated and loose fiberglass."

    I'll specifically ask if that fin took a hit at some point in its life.
  16. Capt Ralph

    Capt Ralph Senior Member

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    Did anybody give the props a pencil test when it was up?
  17. TahoeJohn

    TahoeJohn Member

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    Good point and question. Here's upright:
    upright.png

    And here's heeled:
    heeled.png

    I don't know how to estimate that, so I won't even try.

    On this run #4, 2200 RPM was upright; WOT (2300) heeled over. It stayed like this for a minute (seemingly stable at this angle), then we backed off to 2000 and it leveled out. (Or deploying the port tab would level it out, too, as mentioned before.)

    There wasn't significant wind in any of the 4 runs.

    Could a slight power-down on the port engine cause this? During these runs, we did notice that sometimes the port engine was off by 50-70 RPM from starboard at WOT.
  18. TahoeJohn

    TahoeJohn Member

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    Sorry, I'm going to have to profess my ignorance: What is a pencil test?
  19. Pascal

    Pascal Senior Member

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    So after $36k worth of repairs, a surveyor still found delamination around the port stab And recommended removing the whole thing again???

    at this point you need assume major stab work is needed and get $25/35k adjustment on the price.

    btw, is that a cored bottom or solid glass?

    when I removed the old Vospers from my 53 and installed a larger new ABT Trac system, I had my fiberglass guy reinforce the entire area between the outer stringer and hull side (actually up 6” against the hull side) with over 1/2” of glass. And that was on top of a heavyly build 1970 Hatteras hull!
  20. TahoeJohn

    TahoeJohn Member

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    No, the work I listed in post #70 was the $36k after finding the delamination (in post #75). Sorry, I know I've only been providing information piecemeal with a confused timeline. Just trying to respond to questions as they come up.

    According to the surveyor, it's solid glass about 3/4ths of the way up toward the chine, and then cored above that. His hammer hits made that pretty evident.