Originally Posted by BillBoost37
Call it in Rob..
til then...I'm believing the ship/sub builder with years of experience in salt water.
The saltwater is the electrolyte between the anodes mounted on the hull and the hull of the ship. The interior of the ship is not protected. You have to have an anode and cathode in an electrolyte and the anode and cathode must be metallically connected to have a corrosion cell. If you take away any one of them you do not get corrosion. Electrons flow from the anode to the cathode through the metallic path. An oxidation reaction occurs at the anode in the electrolyte, thus it looses positive ions and in the case of steel it is Fe++. A reduction reaction takes place at the cathode. The electrons passed to it from the anode react to the electrolyte to change positive ions in the electrolyte to neutral ions. H+ goes to H2. (Think why lead acid batteries give off hydrogen gas). The anode is loosing material and the cathode does not. This is why all anodes must be replaced eventually. Here is a basic corrosion cell:
Here is a picture showing how one portion of a metal takes on the role of the anode and another takes on the role of the cathode. Ions are passed through an electrolyte. If there is no electrolyte ions can not flow so the anode you put on your car will not act as the anode to the car body unless there is electrolyte connecting it. Corrosion will still take place locally where an electrolyte is present.
But hey, my job is corrosion engineering and I have NACE certification so what would I know about this stuff anyway?