The Only Anode That Works in All Types of Water
The aluminum alloy used in Navalloy anodes is very different from normal aluminum. It includes about 5% zinc and a trace of Indium, which prevents the build up of an oxide layer.
Aluminum anode alloy provides more protection and lasts longer than zinc. It will continue to work in freshwater and is safe for use in salt water. Aluminum is the only anode that is safe for all applications.
Navalloy® has a higher protection voltage than zinc.
This particularly important when protecting aluminum components, like an outboard motor, which is an "active" metal.
Navalloy® lasts up to 30-50% longer than zinc.
Zinc anodes can form a coating in freshwater after a few months, which will stop them from working. Navalloy® anodes will stay active.
Alloy meets ABYC (American Boat and Yacht Council) requirements for use in all types of water. (E-2 - Cathodic Protection Technical Standards, July 2008)
Navalloy® works immediately on re-immersion whereas zinc forms a non-porous layer which does not work unless rigorously cleaned.
Navalloy® does not pollute - zinc is a toxic metal and pollutes the water. Navalloy® contains only about 5% zinc. Zinc anodes are 99.9% zinc. Environmental agencies have determined that zinc sacrificial anodes are a major cause of pollution in marinas and in some cases zinc anodes are being banned (Maryland).
Navalloy® anodes are made to the military specification MIL-DTL-24779B(SH) and contains approximately 95% aluminuum, 5% zinc, 0.02% indium and less than 0.3% of other trace elements. The alloy is cadmium free.
Zinc is 2 ½ times heavier than the same sized Navalloy® anode.
THERE IS NO SITUATION WHERE ZINC IS BETTER THAN ALUMINUM !
Magnesium is the most active metal on the Galvanic scale. It can be used in freshwater, but care must exercised. Magnesium can over-protect aluminum hulls or outdrives in salt or brackish water or even polluted freshwater, causing paint to be lifted with resulting corrosion. Even a few hours immersion can cause severe damage.