Sacrificial or martyr anodes absorbs the oxidation that occurs in salt water and work similar to the anode in a RV hot water tank. I'm to lazy to spell it all out so goggle it. I have run all over Prince William Sound and Cooks Inlet in a couple of 26' boats, one was fiberglass and one was aluminum. I also took the aluminum one on a couple of thousand mile river trips on the Yukon and Koyukuk Rivers and beached it often when bear hunting and clam digging. Doing that with a glass boat boat not as much fun.
Every glass boat I was on hide a smoother ride over all then the aluminum boats I was on. Aluminum boats have more condensation issues. Here in Alaska aluminum is the hands down favorite for charter and private use for a reason. Durability and upkeep.
