Sacrificial anodes....zincs

Discussion in 'Washington Fishing Reports' started by fishing fanatic, Aug 20, 2018.

  1. fishing fanatic

    fishing fanatic Well-Known "Member"

    Location:
    Alger, WA
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    jason
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    28’ almar sounder //16' lavro
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    69CCFC91-8078-4E04-9321-E6EAFE6AAFDC.jpeg So I’m reaching out to those in the know! I’m planning on bottom paint, I’m not going to plug into shore power, I’ll never ground to the hull and I’ll certainly bond everything but what is the correct material or materials for sacrificial anodes on my almar? As in any condition besides pure fresh water? I’m planning on weld ons on stand offs like the picture. I’ve currently got a zinc mil spec welded on.
     
  2. Walker Inc.

    Walker Inc. I've posted enough I should edit this section

    Location:
    Port Orcahrd, WA
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    Patrick Walker
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    33 ft. Coldwater Walkaround
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    Aluminum annodes because @Omakase and @goatram say so. Enough said. And Coldwater says so too!
     
  3. kenzmad

    kenzmad I've posted enough I should edit this section

    Location:
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    jamie
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    nwj 218 lightning
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    Bob AKA Omakase sent me here for replacements. https://www.boatzincs.com/

    Aluminum is what he has me running. 2 years in the marina, his paint, his anodes. Plugged in all day, every day. No issues. Trim tab anodes corroded 3x faster than hull anodes.
     
  4. fishing fanatic

    fishing fanatic Well-Known "Member"

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    Alger, WA
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    jason
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    Is there harm in running a zinc on one side and aluminum on the other?
     
  5. fishing fanatic

    fishing fanatic Well-Known "Member"

    Location:
    Alger, WA
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    jason
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    Goatram won’t answer this question? Come on man.... we know you know
     
  6. kenzmad

    kenzmad I've posted enough I should edit this section

    Location:
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    jamie
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    The way Bob explained it to me was, zinc is more noble than aluminum, my boat is aluminum. All they would have found was a nearly new zinc anode and a corroded boat on the sea floor. I am no expert, but after running factory zincs for years and they were still in good shape, and now replacing aluminum ones yearly. I am staying with aluminium. Get ahold of Omakase, dude knows his shit and wait til you see his shop. Can eat off the floor there.
     
  7. sgwill122

    sgwill122 I've posted enough I should edit this section

    Location:
    Redmond/WA/USA
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    Stephen
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    'Lady Karen' 28 Duckworth Offshore
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    You want aluminum anodes. Heres a couple paragraphs I found on google.

    You haven’t heard of using aluminum anodes for everyday applications? The primary advantages of aluminum over traditional zinc anodes are: aluminum is well suited for use in fresh, brackish and seawater, making it appropriate for virtually any vessel and especially for those that move between these environments; and aluminum anodes pack a greater electrical punch than their equivalent weight in zinc, which in turn means they last longer. Although the price fluctuates with the market for metals, they are typically no more costly than zinc anodes, and aluminum anodes are lighter than zinc by a factor of two and a half.

    There are still more advantages to aluminum anodes. Typically, when exposed to fresh water for a month or two, zinc anodes develop an aluminum-hydroxide coating that inhibits the activity once the boat returns to seawater. A similar phenomenon occurs with zinc anodes in vessels that are hauled out and the anodes form a non-porous layer. Unless vigorously removed, that layer acts as an insulator, preventing proper protection thereafter. Aluminum anodes are immune to this phenomenon.

    Outboard manufacturers whose products are destined for fresh water typically specify aluminum anodes (or magnesium, although this alloy should be used only in fresh water). Among corrosion experts, the advantages of aluminum have been known for years, but obtaining aluminum anodes in a variety of configurations has often been a challenge.”
     
  8. goatram

    goatram Notable Member Gate Keeper to the Great Northwest

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    Stanwood, WA
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    grrrrrrrr
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    Aluminum! Do not mix! The zinc's will be in great shape and the Aluminum anodes will be gone. I do like the weld on ones. Direct contact with no possible way for corrosion to get in between the boat and the anodes. If you run the bolt on they need to be removed and contact surfaces cleaned as needed to remove the surface corrosion.

    I did try/started to answer Sunday night around 6 when I came in for dinner But the fucking computer and Windows decided to perform an update and auto shutdown and the loss of my post. Sorry but my goats were in the lower pasture and my fence and gate were down. That had the priority. They have no water there and the hay feeder is by the barn. So now you know the rest of the story.
     
  9. blindpig

    blindpig Member

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    Lynden
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    Erik
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    I'm no expert on sacrificial anodes but one thing that should be made clear is that I hope you are all talking about aluminum/zinc alloy anodes. If the anode were made of pure aluminum it would do no good whatsoever as it would be made of the same material as the boat itself. Unless I'm missing something anyway...
     
  10. ShadowX

    ShadowX I've posted enough I should edit this section

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    Alex
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    The site below has good information on the application of different types of anodes depending on your situation. According to the site, "If a vessel remains active in saltwater on a regular basis, both zinc and aluminum anodes will work. If sitting for periods of time in saltwater, zinc is the way to go."

    https://citimarinestore.com/citiguide/when-to-use-zinc-anodes-over-aluminum-anodes-on-a-boat/

    The reason why zinc is use more often is because it has a higher anodic value based on the electronegativity charts. It is more reactive than aluminum. Typical zinc anodic index is 1.20 while aluminum is only 0.75. The higher the number, the more reactive the element is to corrosion. Magnesium is more reactive, but it has other negative traits and is not commonly used in marine applications.

    Zinc is commonly used because it has a high anodic value and is relatively cheap. You need to make sure there is a good electrical connection between your boat hull and the anode. The sacrificial zinc would erode faster than the metal you are trying to protect. You will need to replace the zinc anodes more often then aluminum anodes.

    If you are using an anode with the same anodic index as your boat, it may not offer any protection at all. Most of the anodes are actually aluminum/zinc/iron/copper alloys and not pure aluminum for this reason. It has a higher anodic index than pure aluminum to protect your boat. You just have to be more careful when choosing aluminum anodes to make sure it has a high enough anodic index to protect your boat.

    https://www.pemnet.com/design_info/galvanic-corrosion/

    https://www.galvotec.com/pdf/Cat_Aluminum_KT.pdf
     
    Last edited: Aug 21, 2018
  11. goatram

    goatram Notable Member Gate Keeper to the Great Northwest

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    grrrrrrrr
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    Your missing on 7 cylinders. Do some research then he jump in again.
     
  12. Omakase

    Omakase Well-Known "Member"

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    Kitsap
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    Bob
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    Wow, that post by shadowx is very misleading, didn't read the links tho . . .

    Take it to the bank, every aluminum boat I get in for bottom paint that has been equipped with zinc anodes has some (or a lot) of evidence of galvanic corrosion and the zinc anodes show little to no activity. Boats that have mil-spec aluminum anodes attached (and have never had zinc) are untouched.

    Mil-spec aluminum anodes (Martyr and others) are intentionally not pure aluminum, they have trace amounts of other metals blended into the melt that enable them to be slightly more active (willing to sacrifice themselves) than zinc anodes which makes all the difference when it comes to protecting aluminum boats especially those boats that have extruded aluminum chine strips and/or extruded angle strakes (Raiders, Hewescrafts, Wooldridge, etc.) but all brands even heavy plate builds need aluminum anodes.

    Don't mix zinc and aluminum anodes on an aluminum boat, say for instance aluminum anodes on the outboard motor (which should NEVER be zinc) but zinc anodes on the transom. The motor anodes will try and protect the entire boat (and get used up quickly) while the zinc hull anodes will just sit there and do nothing.

    Could go on about this but 'nuff said . . . get rid of your zinc anodes on aluminum boats!

    BTW, late summer slowdown in the bottom paint shop here (happens every year) so good time to do something nice for your boat!
     
  13. fishing fanatic

    fishing fanatic Well-Known "Member"

    Location:
    Alger, WA
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    jason
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    Bob, thank you so much for this and thank all of the others as well for chiming in!!!!
    On another note, the second my boat is dipped into the drink to achieve a waterline with all of its new fixings you will be asked for available times to bring it to your spot for some bottom love. Unfortunately I’m still a few months out.
     
  14. Omakase

    Omakase Well-Known "Member"

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    Bob
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    Would love to paint your Almar when it's ready Jason

    Check out our bottom job pics at our facebook page: Agate Pass Marine (going to work on a real web page this winter)
     
    Last edited: Aug 22, 2018
  15. blindpig

    blindpig Member

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    Erik
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    Appears as though I were running smooth enough. The aluminum anodes are alloys as I stated. Guess you might be looking at a tuneup goat.:p

    Preparing for incoming shrapnel. .LOL
     
  16. goatram

    goatram Notable Member Gate Keeper to the Great Northwest

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    grrrrrrrr
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    Still Missing Brain Cells and Spark Plugs. Bob Gave you a partial Tune up! You need to Get Smart!
     
  17. fishbadger

    fishbadger Member

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    fishbadger
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    .Grady Gulfstream 232 "Herd of Turtles"
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    Interesting topic. I'm no expert, but I'll throw my observations in the hopper. Given my boat is fiberglass, not metal, and it is moored year round, but my zinc anodes (on trim tabs) get used up far far far faster than the aluminum alloy anodes on my motors. And the zinc's actually have a good deal less surface area than the aluminums, but they degrade a lot faster. I check them all and knock off the fuzz on all the exposed anodes every time I pull the boat to trailer it, which is pretty often. If aluminum is more sacrificial than the zinc, then why is that? Is it a function of my boat being fiberglass (doesn't seem like it would matter), or is it the location of the zinc's on the trim tabs (which are non-painted metal). Or is there more to it?

    fb
     
  18. goatram

    goatram Notable Member Gate Keeper to the Great Northwest

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    grrrrrrrr
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    Do your motors rest in the water? Mine are completely out of the water.

    Are the trim Tab anodes the only ones on the boat?
     
  19. fishbadger

    fishbadger Member

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    fishbadger
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    .Grady Gulfstream 232 "Herd of Turtles"
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    Motors are out of the water, but the Aluminum alloy anodes I'm referring to are in the water, mounted on the bottom-side of the motor trim pumps if that makes sense,

    fb
     
  20. blindpig

    blindpig Member

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    Erik
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    Because Zinc anodes are MORE sacrificial than aluminum alloy anodes as long as they don't get an oxidation layer over them.
     

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