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Thread: White Powdery Substance on Boat

  1. #1

    Default White Powdery Substance on Boat

    I was just out checking out my boat (more like dreaming of summer!), and I noticed that there is some white powdery substance on parts of it. I have a North River skiff, and it seems like most of this substance is on the cleats.

    Is this some kind of oxidation? Is it bad for the boat? If so, how do I fix and prevent it?

    Thanks for your help!

  2. #2

    Default

    Quote Originally Posted by Ruger01 View Post
    Is this some kind of oxidation?
    It is likely dissimilar metal corrosion.

    Quote Originally Posted by Ruger01 View Post
    Is it bad for the boat?
    It could be; eventually.

    If your cleats are bolted on remove them and clean the surface's and apply a coat of water resistant grease to the contact surface and reattach the cleats. Don't overlook the "bolts" as a source of the corrosion.

    You may want to make this a part of your "annual" boat maintenance program.


  3. #3

    Default

    I would not be nearly as concerned about what is visible, as opposed to what you cannot see. Between the cleats and hull, is what you really need to be focused on. Sometimes boat builders used a good marine grade substrate for the hull and slack on the add ons, like cleats, tabs, platforms, etc and their fasteners. Even some stainless hardware is inferior for boat building. You have to use the very best Marine Grade Materials or else you run risk of corrosion. Even then there is considerable amount of prevention needed on the owners part. Rinsing, using products like ACF 50 and other corrosion inhibitors will slow it down. You could also have an electrolisys thing going on, that is difficult to overcome, even through the use of cathodes. A bad/poor ground on any part of the electrical system or poorly installed accessories, will cause electrolisys. I have seen aluminum hulls literally destroyed, eaten out, under the add ons, due to extreme corrosion, and it happened within a few short seasons of neglect. Adding salt water to the equation makes it happen sooner.

  4. #4

    Default

    Thanks for the responses. What's wierd, is that the cleats are also aluminum, and are welded to the boat.

    The only difference is that the cleats are a rough (unfinished) aluminum, and the rest of the boat is a finished smooth aluminum (like most aluminum boats).

  5. #5
    Member sayak's Avatar
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    Default White, powdery substance

    Was your boat used in the transport of illegal substances?

  6. #6

    Default

    Quote Originally Posted by Ruger01 View Post
    Thanks for the responses. What's wierd, is that the cleats are also aluminum, and are welded to the boat.

    The only difference is that the cleats are a rough (unfinished) aluminum, and the rest of the boat is a finished smooth aluminum (like most aluminum boats).
    I meant to type ANODE in my earlier response, don't know where the term cathode came out of my fingertips. Sometimes boats require more than one, to do an adequate job of reducing corrosion. When you inspect it again, I would look very carefully at the welds and under fuel tanks and cushions, etc. The most likely places for serious corrosion is where moisture, salt, dirt and acidic gunk collect. The best cleaner I have found for aluminum boats is Naval Gel. It works wonders. Then put a protectorant on afterward. I use ACF50 for a lot of applications, and it penetrates those cracks and crevices pretty good too. Your description would lead me to believe the cleats are not the quality of the hull. Therefore, what is happening between the two is reason for attention.

  7. #7

    Default

    This past spring I uncovered my boat and had a similar issue. I noticed that there was a white granular substance on many parts of my boat. Particularly it seemed to be on the stainless nuts and bolts. The white stuff looked like salt, it tasted salty too. Any ideas what this stuff is? I can't figure out how salt crystals could have gotten on these parts, so I'm assuming its some sort of corrosion. I don't have corrosion issues during the summer operating months, so it seems weird to have them during the winter. Any thoughts on what might be causing this?

  8. #8

    Default Corrosion Basics & Hull Potential Test

    A good link describing corrosion in marine environments and how to perform a hull potential test to see if you have a problem.


    http://www.seaguard.co.nz/corrosion.html

  9. #9

    Default Silver Silver Chloride Reference Electrode

    Here is a site that sells the necessary electrode to do your own hull potential testing. It is $98. You will need a good multimeter to do the test.

    http://www.boatzincs.com/corrosion-r...ode-specs.html

  10. #10
    Member Magnum Man's Avatar
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    Cool stainless

    Stainless steelhardware nuts an bolts can do bad things to your aluminum boat. Im always fighting that crap. I say just keep your zincs in good shape and do a lot of rinsing with the garden hose. My theory is the salt is more in the air than in the water.

  11. #11

    Default Oxidation

    It sounds like normal oxidation to me. The cleat is probably made of a slightly different alloy than the hull it's welded to. And different alloys will oxidize differently. You can use a chemical called Zepalume do de-oxidize your entire aluminum boat, and the cleats...and make it shine too. Just spray it on and rinse it off.

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