Over-the-side Zinc Fish 6 pound Grouper, with 20 foot vinyl coated galvanized wire. Zincs are used to help prevent galvanic corrosion of thru hulls, masts, engines etc.
Add the protection of a zinc without the complication of mounting zincs on shafts, drilling holes in rudders or the hull. I toss my fish over the side while at anchor. It is simple and effective.