Zinc Anodes: Get the Ultimate Protection for Your Boat, Big or Small

Mixture of different metals getting in touch with salt water provokes corrosion. Without getting too technical, zinc anodes protect metals on the boat exposed to the harsh underwater environment by being the most likely to corrode. Basically, the zinc anodes corrode before the boat does, saving you costly repairs and headaches. Note that zinc anodes only work when they are electrically connected to the items they are intended to protect. The zinc anodes will be set up as part of ships’ bonding system and will be connected inside the boat via the long bolts. 

Components of Boat Zinc Anodes Protect

There are a variety of metals on your boat’s hull with salt water all around. A typical boat probably has some stainless steel (prop shafts and other components), different varieties of bronze (propeller, thruhulls etc) and possibly aluminum (outboard motor or outdrive components). With these different metals in salt water you get what amounts to a battery action. The different metals have different electrical charges and the most active will corrode – pieces of the metal dissolving and depositing on the less active metals. The idea of using zinc anodes is that the zinc becomes the anode here and will slowly corrode away protecting the other metals.  

Warm water speeds up this reaction. Change zinc anodes when they half gone. If you are in for a swim, you can check zinc anodes underwater and plan out the next change. Well, fresh water is a much less corrosive environment and corrosion is much slower. However, zinc anodes do not work well in fresh water. In that case, you are recommended to use aluminum or magnesium, but be sure not to mix zinc anodes. 

Zinc Anodes

It’s pretty easy to check and change the zinc anodes and absolutely important to the underwater health of your boat. The marine environment is hard on metal components, and you need to protect them.

Zinc Anodes Fortify Boats: Safeguard against Saltwater Corrosion

Zinc anodes have, for many years, been the go-to anode for boaters. Zinc is a less active metal and thus last longer in the marine environment. However, zinc anodes are realistically only good in salt water. When used in fresh water for extended periods, zinc anodes can produce a zinc hydroxide layer rendering them useless. So, if your anodes have been on your engines for a number of years, and still look like new, then it’s worth pulling them off and replacing them. Zinc anodes are quite heavy as opposed to aluminum anodes which are typically much lighter.

So, the next time you are servicing your outboard, remove your zinc anodes and have a look at them. If in doubt, replace them and you’ll be giving your outboard the best protection possible against corrosion.