Bilge Zinc ?

[backcreeksailor]

During the course of cleaning out the bilge, I found a corroded disk shaped piece of metal, about 5" in diameter" just laying loose in the deepest part of the bilge. During a trip to West Marine, I saw a zinc that was exactly like the size and shape of my mystery disk, so I'm relatively sure that's what it is.

I've heard of people attaching zincs to a keel bolt, and one of my keel bolts actually has a threaded screw mounted on one side with a bolt on it, (nothing currently attached to it). But would this disk actually do anything if it was just laying in the bottom of the bilge without being directly connected to anything?

Should I attach a zinc to the aforementioned keel bolt mount?

[backcreeksailor]

No one's willing to hazard a guess on this one...?

Even though it was corroded, I'm assuming that really wasn't doing anything since it was just laying on the fiberglass bed of the bilge and wasn't in direct contact with the keel bolts which are the only metal items in the bilge from what I can see.

No one else here has a zinc in their bilge or connected to their keel bolts?

[sailingdog]

The threaded screw mounted on one side might be for a lightning ground or bonding the through-hulls.. Photos would help...

[LittleMissMagic]

If it wasn't connected to anything, assuming it is a zinc anode, it isn't doing anything.
On that same line of thought, if there is no water in your bilge, an anode won't do anything either. Sometimes you see steel boats with zincs in the bilge, but these are usually worn out workboats or tugs that keep a fair amount of water in the bilge.
If there is no electolyte, i.e. seawater, for the zinc to conduct an electrical charge, it will be inactive.
If your bilge stays dry, there is no reason to attach the zinc to the keel bolts or anywhere else.