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Seacock problem

Discussion in 'Technical Discussion' started by Seadog, Feb 3, 2010.

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  1. Seadog, Feb 3, 2010
    #1
    Seadog

    Seadog New Member

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    Hi all

    In my Bertram 38, I have 4 pairs of Wilcox Crittenden seacocks. On the strainer connected to one of the seacock’s there is hardly any pressure coming from the one seacock, well not enough to allow the generator to pump it through it’s system, iv checked the impeller in the generator and it’s all good, so I came to the conclusion that there might be a problem with the seacock. On closer inspection, I discovered that the locking nut on the seacock was corroded right off, could this block the seacock in away? And how much pressure should be coming out the pipe?
    My next question is im planning to replace another seacock, but I see that the company that made the seacock’s (Wilcox Crittenden) has sold out to another company, so if so would I be able buy a new Wilcox seacock some where? Or could they be re-engineered? Here are some pictures of the generator seacock with the locking nut missing. Please, hope you guys can help.

    Thanks

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  2. dennismc, Feb 3, 2010
    #2
    dennismc

    dennismc Senior Member

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    Until you do a haul out, try putting a set of vice grips on the shaft and see if it opens and closes, if it is seized, tap the body with a 2 lb hammer to shock it a bit, then try again, the other thing to do is remove the drain cosk and install a st stl grease nipple to help lubricate the cock, (do all the same).
  3. m2m, Feb 3, 2010
    #3
    m2m

    m2m Senior Member

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    I have seen the problem that you describe before. It may be that the valve is only half way open. There are lots of companies out there that make sea cocks, Groco,Forespar,Apollo, Buck Algonquin to name a few
  4. Pascal, Feb 3, 2010
    #4
    Pascal

    Pascal Senior Member

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    when you say "how much pressure should there be out of the pipe" do you mean how much water shoudl flow in when open? depends on how far below waterline the sea cock is located, there shuodl be a steady stream.

    things to check before ASSuming the sea cock is reducing flow is for something stuck in the intake outside, under the boat, as well as something stuck in the sea cock or in that elbow. that's happened to me before... piece of barnacle.

    also, make sure that someone didn't change a bad impeller and left the pieces downstream, usually at the heat exchange inlet. many mechanics/captains/owners are often too lazy to trace all the pieces, resulting in reduced flow.
  5. Beau, Feb 3, 2010
    #5
    Beau

    Beau Senior Member

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    Seadog. Be careful if you use the "hammer" method. The seacock itself can be corroded and degraded. In that condition it is easy to break off - then you'll have plenty of flow!
  6. NYCAP123, Feb 3, 2010
    #6
    NYCAP123

    NYCAP123 Senior Member

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    Big ditto on that. This should also be a caution to all boaters that seacock operation should be checked several times each season and all corrosion removed. Also check for electrolysis. That little seacock is all that stands between you and Davy Jones. Installing South Bay strainers is also a good idea when you haul.
    BTW, when you fire up the gen check the strainer. If it stays full you'll know that your problem is further up the line as Pascal suggested. If it goes empty you're at your problem.
  7. Adad, Feb 3, 2010
    #7
    Adad

    Adad New Member

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    Isnt that nut on the left side an indicator of the valves position? Valves Ive seen like that usually have a line stamped in them.
  8. NYCAP123, Feb 3, 2010
    #8
    NYCAP123

    NYCAP123 Senior Member

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    Given the corrosion, handle direction yes valve position maybe.
  9. Ormond Bert54, Feb 3, 2010
    #9
    Ormond Bert54

    Ormond Bert54 Senior Member

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    and ... basic maintenance says to confirm proper operation of all seacocks regularly and at least at season begin and season end. (season end because that would be a great time to fix such issues). So .. it's a great topic and a great time to check the rest of the seacocks onboard.
  10. Pascal, Feb 3, 2010
    #10
    Pascal

    Pascal Senior Member

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    i usually check them once a month... air con, water make and genset seacocks are used monthly to clean the strainers anyway, mains more rarely so excercizing them monthly is a good idea.
  11. dennismc, Feb 3, 2010
    #11
    dennismc

    dennismc Senior Member

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    If the seacock is so corroded that tapping to introduce shock causes it to fail, then haul you boat now....thats, why you are supposed to carry wooden tapered plugs aboard for every size of through hull fitting. a lack of confidence in the integrity of any through hull fitting is no way to go to sea.
  12. Capt J, Feb 3, 2010
    #12
    Capt J

    Capt J Senior Member

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    The nut on the backside, is to loosen or lock the seacock handle. Turn the seacock handle side with vice grips and see if it turns. I have seen where the handle wallows out and the handle is straight up and down but the valve itself is only partially open. Make sure the valve is open all of the way. If the valve is not open all of the way, you will not get bubbles or a half-filled sea-strainer as said above because there shouldn't be anywhere for the air to enter into the system. It is also possible something is partially blocking it on the outside such as a plastic bag, or barnacles. If your careful take the hose off of the raw water pump and lower it in the bilge and see how much waterflow you have. It should be like a garden hose on full flow.

    You can also replace the seacock with any brand for that size....... I would go with groco or other.
  13. Marmot, Feb 3, 2010
    #13
    Marmot

    Marmot Senior Member

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    There is no "lock nut." The large square bit on the left side of the picture is where the operating handle should go. It is the outer end of a tapered plug. The plug has a hole through which the water flows when the handle is vertical. When the handle is horizontal the hole in the tapered plug is 90 degrees to the inlet and outlet and blocks water flow. There will be a line on the outer end of the square section to indicate where the hole is aligned. The nut shown on the right side is used to hold the plug tightly in the internally tapered body.

    If you have a handle, or a large crescent wrench, hold the square part to prevent it moving (as if it would, then you wouldn't be posting here) and use another wrench to loosen the nut on the right side. Use some good penetrating oil on each end of the taper plug and if safe to do so, use a heat gun to warm the valve body. If the adjusting nut moves, back it off slightly, just a half turn will do. Then use a hammer to try and tap the plug to move it from right to left in the picture. The smallest movement will loosen the taper plug and allow you to rotate the valve. As was mentioned, if you can remove the small plug, install a grease fitting and lubricate the valve by rotating it a few times. Tighten the adjustment nut only enough to prevent leaking around the edges of the taper plug and allow smooth operation.

    Do not completely remove the adjusting nut and tap the small threaded piece that you see or you will destroy it by swelling the threads or even knocking the taper plug all the way out and sinking the boat. Equally important, don't hit the nut so hard you distort the threaded hole in it. Just be careful and don't break anything. Next time the boat is hauled remove the taper plug and reseat it properly and make sure you keep a handle on it at all times as well as routinely operating it to keep it free.
  14. captainJJ, Feb 7, 2010
    #14
    captainJJ

    captainJJ New Member

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    Judging by colour of seacock I would replace without trying to fix. reckon that through hull fastnings will fail with a quarter of a turn. Haul it now and replace.
  15. Marmot, Feb 8, 2010
    #15
    Marmot

    Marmot Senior Member

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    It looks like a normal case of verdigris to me.
  16. K1W1, Feb 8, 2010
    #16
    K1W1

    K1W1 Senior Member

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  17. Pascal, Feb 8, 2010
    #17
    Pascal

    Pascal Senior Member

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    I ve seen seacocks or strainer that were not green in a salt water environment. It s a normal surface reaction which doesn't affect the rest of the metal