Zincs. What do they do?

Discussion in 'Sport Boats' started by LawyerMan, Aug 16, 2012.

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  1. LawyerMan

    LawyerMan Member

    425
    Jul 12, 2012
    Texas Gulf Coast
    270 SLX w/ Sport Arch
    496 Mag DTS, Bravo III, Corsa
    I've never heard of changing Zincs until recently. I've never done it on either of my boats. What do they do?

    How often should I change them? Does my 175 even have them?
     
  2. Cincy Aquaholic

    Cincy Aquaholic Active Member

    Mar 15, 2009
    Cincinnati
    290 SS - 2016 Ford F250 Powerstroke
    Twin 5.7 with Bravo 1's
    "Zincs" which is generally the generic reference to anodes help prevent corrosion on your outdrive due to disimilar metals being in contact. i.e., aluminum casing and stainless steel prop. If you trailer and rarely leave your boat in the water its likely you probably almost never have to change them if they came with them in the first place. Being slipped in a marina with stray current makes the situation worse so slipped boats generally replace once per year.
     
  3. LawyerMan

    LawyerMan Member

    425
    Jul 12, 2012
    Texas Gulf Coast
    270 SLX w/ Sport Arch
    496 Mag DTS, Bravo III, Corsa
    I trailer the boat. Does it make a difference if I run the boat predominately in saltwater?
     
  4. Bucit

    Bucit New Member

    Mar 12, 2010
    St. Petersburg Florida
    2005 280 Sundancer
    2004 SPD-104 Achilles w/ 8hp Yamaha
    Twin 4.3 MPI's with Alpha drives.
    Since your boat does not sit in the water all the time it doesn't make much of a difference if boating in salt/fresh water.
     
  5. ZZ13

    ZZ13 Well-Known Member GOLD Sponsor

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    My 175 sport is trailer-ed in salt water. Anodes will never need to be changed. They have absolutely zero wear in 3 years. Just make sure to do the engine flush and full boat washdown with Salt Away or Salt Terminator after every outing. Keeps the trailered boat looking brand new.
     
  6. Gunn

    Gunn Active Member TECHNICAL Contributor

    Oct 4, 2006
    Potomac River - MD
    2003 280DA and 1995 Sea Ray 175
    Twin 4.3l and 3.0l, all w/ AlphaI GenII drives
    Maybe, maybe not. Why don't you go and take a look at yours and see what condition they are in versus brand new ones? I know on my '95 175 (always trailered to the best of my knowledge) I had to replace the anodes when I purchased it. That was 7 years ago now and they still look pretty good. So you're probably OK, but it's nothing harder than taking a look to see if you need to worry about them or not.

    On your 175, they are all located on the sterndrive unit. Two circular shaped on the rear ends of the hydraulic trim cylinders. One on the underside right above the propeller (may be a flat circle, or may have a "fin" protruding from it on it). One large flat one on the underside at the forward end near the transom, and one around the propeller shaft, behind the propeller.

    Tom
     
  7. LawyerMan

    LawyerMan Member

    425
    Jul 12, 2012
    Texas Gulf Coast
    270 SLX w/ Sport Arch
    496 Mag DTS, Bravo III, Corsa
    I'll take pics tonight and upload them. Y'all can tell me what you think.
     
  8. ZZ13

    ZZ13 Well-Known Member GOLD Sponsor

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Lawyerman, you can see three of them in this pic I took a while ago. The two on the trim cylinders and the one big one just above the prop.

    http://clubsearay.com/showthread.php/35383-hole-for-transducer-cable?p=392026#post392026
     
  9. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled
    V-Drives
    On my previous boats, I would take the anodes off at season end and wire brush the deposits off. This would make them all shinny and ready for the season. You can do this and make them last for several years before eventually having to replace them.
     
  10. Brian 59

    Brian 59 Member

    451
    Oct 5, 2006
    Lockport New York
    280 Sundancer 2004
    4.3 MPI w/ alpha drives
    I have replaced mine every year regardless and I am in fresh water. I thought that wire brushing wasnt a proper thing to do ?
     
  11. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled
    V-Drives
    It's all about the clean conductive surface area... eventually the surface area wears away, but it takes several seasons.
     
  12. Gunn

    Gunn Active Member TECHNICAL Contributor

    Oct 4, 2006
    Potomac River - MD
    2003 280DA and 1995 Sea Ray 175
    Twin 4.3l and 3.0l, all w/ AlphaI GenII drives
    I can't think of a reason why it would hurt?!??

    Sent from my LG Thrill 3D using Tapatalk 2
     
  13. Gunn

    Gunn Active Member TECHNICAL Contributor

    Oct 4, 2006
    Potomac River - MD
    2003 280DA and 1995 Sea Ray 175
    Twin 4.3l and 3.0l, all w/ AlphaI GenII drives
  14. chandalen

    chandalen New Member

    367
    Aug 7, 2011
    Alexandra Bay,NY
    '83 Sundancer 270, Humminbird 593c
    Twin merc 305, with new SEI 106 drives
    Brushing them off with a wire brush is fine. They will develop pits and such.
     
  15. Henry Boyd

    Henry Boyd Well-Known Member

    Apr 24, 2007
    Newburyport, on the peaceful and serene Merrimack
    02' 280 DA
    496 w BIII
    Jim is absolutely correct.

    The purpose of the anode is to corrode before the more valuable stuff does. If you remember your high school chemistry; simply put chemical reactions involve loose electrons on one atom combing with loose protons on another. Its the dissimilar electrical charge thing. When zinc, magnesium, or aluminum anodes are used these will more readily bond with the oxygen in the water and form zinc, magnesium, or aluminum oxide.

    The thing is that anodes on boats that are used temporarily will still form an oxide layer, but not degrade significantly. They will just form an oxide layer. The problem is that this oxide layer will slowly build up and eventually insulate the base metal of the anode from the water. This makes the anode ineffectual.

    Anodes on boats that are in the water full time on the other had degrade quickly and the oxide layer falls away exposing base metal.

    So if you have a small outboard you might want to just replace the anode every year. If you have a BIII on a trailer boat, you might prefer to remove the anodes and clean them. Best choice is some non metallic abrasive. Wire brushing, or steel wool can leave steel fragments behind.

    Henry
     
  16. Loneranger

    Loneranger Active Member

    May 2, 2008
    Knoxville TN
    2000 SeaRay Sundancer 270
    7.4l Mercruiser w/ Bravo III
    It may not make an actual difference but theoretically with a wire brush you are leaving behind bits of metal from the brush on the surface of the anode. If your wire brush is steel you have set up a battery with potential differences with your aluminum, magnesium, or zinc anode.

    I use a nylon brush for this reason although I must say that this is probably all theoretical.

    http://www.amazon.com/Dico-541-774-...TF8&qid=1345243439&sr=1-3&keywords=Dico+brush

    John

    I notice after I posted that Henry makes the same comment about metal fragments in the bottom of his post. My boat lives in a lift for the most part but I hit the anodes once a year to remove the oxidized layer.
     
    Last edited: Aug 17, 2012
  17. LawyerMan

    LawyerMan Member

    425
    Jul 12, 2012
    Texas Gulf Coast
    270 SLX w/ Sport Arch
    496 Mag DTS, Bravo III, Corsa
    Okay. I pulled the boat out this weekend and snapped some photos of my current anodes. What do y'all think? Obviously, there is one missing.

    [​IMG]

    [​IMG]

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    [​IMG]

    [​IMG]
     
  18. chandalen

    chandalen New Member

    367
    Aug 7, 2011
    Alexandra Bay,NY
    '83 Sundancer 270, Humminbird 593c
    Twin merc 305, with new SEI 106 drives
    No need to replace the pictured anodes
     
  19. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled
    V-Drives
    Agreed... just take them off and clean them up.
     
  20. LawyerMan

    LawyerMan Member

    425
    Jul 12, 2012
    Texas Gulf Coast
    270 SLX w/ Sport Arch
    496 Mag DTS, Bravo III, Corsa
    Any idea where I can purchase the missing one? Is it needed? I have the bolt. Does the missing one have a built-in nut?
     

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