Crab Pot Zincs

[justin_c]

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I have heard a lot of complaints about the costs of crab pot zincs.

On average how much are zincs? Types used? Sizes? Number used in season per pot?

J

[michael Mahon]

what are crab pot zincs and what is their purpose?

[rj]

The scientific response

Metals are ranked relative to one another based on what happens when they are in close proximity in the presence of electric current (which is frequently present in water from a variety of sources including dock electric leaks and improper grounding on boats themselves). This is called electrogalvanic action. More "noble" metals tend to attract material from less "noble" metals, with bronze, for example, being more noble than mild steel. Less noble metals become pitted, and eventually rotted through. It has been found that placing samples of a metal that is extremely low on the scale (that is, one that will lose material to just about any other metal) in the general area, like near bronze propellers and shafts, causes the current to waste its energy taking away the "sacrificial" metal (and in fact coating the other metals with it). Zinc is the common choice for such sacrificial "anodes", and lobstermen might place zinc on their traps if the traps are composed of dissimilar metals like bronze and steel to deter deterioration of the steel.

the crabbers response

Being a commercial waterman from Maryland, I installed zinc bars in my crab pots to stop them from rusting out. A crab pot without a zinc bar only lasts one to maybe one and one-half seasons. With a zinc bar added annually the life of a pot extends four to five years. The same theory applies to the hulls of wooden boats, saving the nails! They are also found on outboard motors, which stops electrolysis from eating the lower units. Yearly replacing the zinc bars would cost less than replacing crab pots, lower units or run the risk of planks coming loose on wooden-hulled boats. Thank God for zinc!

[michael Mahon]

rj, thanx for the info, will upgrade the pots this winter.