Every household hot water heater has two lines of defense to protect its interior from corrosion. First, the steel tank is lined with a ceramic coating baked on at 1600 degrees. This coats most of the interior of the tank, but like an old ceramic lined camping cup that rusts at the lip, it still has some exposed steel at seams, fittings and where there are flaws in the coating.

As a second line of defense, every household hot water heater has at least one and often two 48" long anodes to protect the internal tank from corrosion. By sacrificing itself to corrosion it protects the steel tank from corrosion. In fact, if you haven't replaced yours in five years, it's probably sacrificed itself completely and needs to be replaced!

The internal tank of the marine hot water heater in you boat is made of aluminum not steel. This prevents it from rusting through form the outside but also precludes coating it with ceramic from the inside for protection. Without a ceramic coating, the tank desperately needs the protection of an anode.

Unfortunately, due to their small size, limited space on the end of the tank, and as many as seven ports on one end, there just isn't enough space for an additional port for the typical anode.

Catalina Direct has a solution! Simply remove the drain valve from the end of the tank and replace it with our special magnesium anode. It is made especially to guard against corrosion of the aluminum alloy tank and fits the same thread as the valve. You can still drain the tank for winter by simply removing the anode.

• Overall length: 4"
• Diameter of anode: 3/4"
• Wrench size: 1-1/16"

Will not work on the earlier Atwood water heaters used in the late 1980's.

Caution: Don't attempt to use the typical zinc anode commonly used to protect the copper of a heat exchanger. Zinc is not far enough away from aluminum on the anodic index and will not protect the aluminum tank from corrosion. C-445