I was recently reading an article about an innovative company in the Pacific Northwest called Canada Metal (Pacific) Ltd. They manufacture cadmium free aluminum alloy anodes.
You may ask, “How does that relate to my boat?”
Well, pretty much everything that is immersed in water (boat, watercraft, dock) require anodes to protect them from corrosion. Anodes are made from zinc (saltwater), magnesium (fresh water) or aluminum (fresh and salt) and attach to the hull, shafts, trim tabs, etc. The traditional zinc anodes corrode over time and release tiny amounts of cadmium into the water. Cadmium is carcinogenic, and if you imagine all the boats and all the marinas in the world, that adds up to a lot of carcinogens in the water.
Canada Metal’s Aluminum Anode
Canada Metal created an environmentally friendly aluminum anode which corrodes without releasing toxins.
“It’s a solution for boaters worldwide, if we can educate them to use aluminum instead of zinc,” said Jason Mitchell, Canada Metal’s International and Canadian account manager.
They also weigh far less than their zinc counterparts and cost less. A zinc Diver’s Dream weighs about 2.25 lbs whereas an aluminum Diver’s Dream weighs 0.87 lbs. Historically zinc anodes have been less expensive than aluminum, but that’s no longer the case. A typical zinc Diver’s Dream plate retails for about $ 64.99 whereas an aluminum Diver’s Dream plate retails for $39.99. They are sold under the trade name Martyr and are available at West Marine and Steveston Marine & Hardware.
Not all anodes work in all conditions. For example, if you moor your boat in saltwater but move to fresh water for an extended time, the surface of a zinc or aluminum anode will be covered with an off-white crust of oxide which seals it and stops it from working even when returned to saltwater. Zinc anodes will do the same in brackish water whereas aluminum will continue working. If you boat mostly in fresh water, then magnesium anodes are best however they become very inactive in saltwater after only one week.
Also, remember that you cannot mix types of anodes. If a boat has multiple anodes they must all be the same or only the least noble among them will be doing all the work of protecting your equipment.