purple_stars wrote:
hi folks, quick question ...

i've been reading a lot about sacrificial zincs for protecting steel
hulls and i haven't been able to figure out from my reading where they
are mounted. my reading material says how they are mounted, like
welding, or hanging on metal wires, etc, and it says where they are
mounted in relation to each other ... that is, certain distance apart
to protect such-and-such square feet of hull, etc ... but i have more
basic questions like, do they have to be on the outside of the hull or
can they be inside ?

They must be outside the hull.

and .. do they have to be submerged in seawater
or do they work in the air ?

They must be submerged in seawater and will not work otherwise.

i can't tell if you have to weld them to
the underside of the boat so that they are in the seawater or if you
can just hang them from a wire inside the boat somewhere in the air
where they aren't in the way (while being electrically connected to the
hull of course).

They do not have to be physically attached, but their range of effective
protection will generally be greater if they are. Hanging the anodes is
not a particularly attractive solution if/when the vessel is in motion,
obviously.


thanks again for the help.

Keep in mind that the hull and the zinc anode form a galvanic couple
only when both are immersed in seawater and connected electrically, and
that the ability of the anode to protect the steel will depend, among
other things, on the zinc's surface area and the distance between the
zinc and the steel surfaces. And, of course, no paint on the zinc!

Good luck,

Chuck