Jon boats are very versatile watercraft that are used mostly on inland waterways. Although you will most likely see a Jon boat navigating freshwater lakes, rivers, creeks and ponds not all inland waterways are filled with freshwater. You might have a saltwater lake nearby and may be wondering if your Jon boat can navigate it safely without falling apart in a few months.
Jon boats can go in saltwater as easily as they can go in fresh water. But, fiberglass and wooden Jon boats will be more durable than aluminum ones. Saltwater corrodes aluminum, so if you have an aluminum Jon boat you will need to protect it with specialized products to minimize galvanic corrosion.
- Jon boat construction materials
- How to protect your Jon boat in saltwater
- Galvanic corrosion protection
- Steps to prevent corrosion
Jon boat construction materials
The materials your Jon boat is made from will determine whether using it in saltwater, without taking proper precautions, is a good idea or not.
Although both freshwater and saltwater will eventually corrode any type of material some materials are more durable than others when it comes to saltwater.
Wooden Jons and saltwater
If you have a home-built Jon boat it will likely be made of some form of wood, such as the plywood Jon boat we showed readers how to build here. Obviously wood will degrade quickly in any sort of water if it is not properly protected. However, saltwater is no more corrosive to wood than freshwater is.
A wooden Jon boat will need no further protection against the effects of saltwater if it is already protected against the corrosive effects of freshwater.
If you have a wooden Jon boat it should already be protected with the appropriate type of paint, such as waterproof epoxy-based coatings, or a good coat of marine grade varnish. This will give your boat all the protection it needs against saltwater damage.
Fiberglass Jons and saltwater
Fiberglass Jon boats are rare. You don’t often see them on the water.
A fiberglass boat will the most durable type of boat used in a saltwater environment. However, if you own one you should still take steps to protect it from the abrasive nature of saltwater.
Good fiberglass one-part paints are usually polyurethane based and these can be manually applied by brush or roller or can be sprayed on.
Alternatively you could use a colored exterior gel coating instead of paint to ensure the fiberglass is well protected.
Aluminum Jon and saltwater
If you have an aluminum Jon boat you will need to take steps to protect your boat from saltwater.
Aluminum and saltwater don’t mix well.
Saltwater is highly corrosive to aluminium. As we pointed out in this article the vast majority of Jon boats made in the USA and Canada are made from aluminium.
So, the odds are your boat is made from aluminum.
The following manufacturer’s Jon boats are all made from aluminum:
- Gator Trax
If you followed our Jon boat buyer’s guide then you will most likely have bought a boat from one of the above mentioned manufacturers. This means you have an aluminum Jon boat and will need to take steps to protect it if you want to use it in saltwater.
There is a process that occurs when aluminum and saltwater meet called galvanic corrosion.
Saltwater is an electrically conductive solution. When a metal comes in contact with this solution it will give up some of its electrodes to another, but dissimilar, metal that is in the same solution. The effect of this is what we see as corrosion and decay.
Aluminium is very active chemically. This means it is very susceptible to galvanic corrosion when it is around most other metals. Don’t think that all you have to do is remove other types of metal from your boat. When aluminium is not in contact with another metal the corrosion will still occur but it will happen at a much slower rate.
I won’t bore you too much with the science behind galvanic corrosion, suffice it to say that this type of corrosion is electrical in nature, acts fast and has a devastating effect on an untreated aluminum boat.
So what can we do to protect our aluminum Jon boat from galvanic corrosion if we really want to use it in saltwater?
How to protect your Jon boat in saltwater
We will assume that you have an aluminum Jon boat from this point forward. If you have a Jon made from a different material then simply follow the advice given in our article how to paint a Jon boat being sure to use the appropriate protective products for your given construction material. For everyone else, keep reading this article.
Many Jon boat owners think that merely applying bottom paint is enough to protect their boat from the corrosive effects of saltwater. Although a good bottom paint is highly recommended just relying on that alone is a mistake.
The American Boat and Yacht Council (ABYC) recommends that “aluminum vessels shall have a protective paint coating that provides a high [electrical] resistance barrier between the aluminum and the water.” So ordinary bottom paint isn’t enough. You need to take additional measures to protect your aluminum boat from electrical corrosion.
So how do we do that?
I’m glad you asked. Let’s take a look at how to protect your aluminum Jon now.
Galvanic corrosion protection
There are a number of steps you can take to protect your aluminum Jon boat from galvanic corrosion and we will look at them now.
To begin we see how the ABYC’s advice of applying electrical resistance paint can help protect the metal on your boat.
Aluminum boat paint
A ordinary bottom paint is not enough to protect your aluminum Jon boat from galvanic corrosion. You should only use paint and coatings that are designed for use with aluminium.
Interlux and Pettit sell copper-free, aluminum-compatible paint systems. You can also get an excellent marine ablative antifouling bottom paint that is copper-free and will offer great galvanic corrosion protection as well as antifouling protection.
The above mentioned paints can be easily applied by brush, roller or spray gun and come with tech support and good instructions.
It does take some effort to get the application right if you are using paint but the results are well worth it. You will need to set aside sufficient time for preparation and need to be patient in the application if you want to do it right though.
A very popular method for protecting your aluminum Jon from galvanic corrosion is to attach Zinc Anodes.
As we mentioned previously, aluminum is very susceptible to galvanic corrosion when it is around most other metals but there are two exceptions that we can use to our advantage – zinc and magnesium!
So, using anodes made from zinc, and attaching them to your aluminum Jon boat, can help battle the damaging effects of galvanic corrosion.
How does this work?
Well, the zinc anodes are attached to your boat at points of saltwater contact, like the bottom of the hull, and then start to act as sacrificial metals that will corrode instead of your boat’s precious aluminium. This is why zinc anodes are often called sacrificial zinc anodes.
Zinc is not as chemically active as aluminium and can act as a form of protection for it. By electrically connecting the zinc anodes to the aluminium of your boat the anodes will act as a “first layer” of protection. The zinc will shed its electrodes first, stopping the aluminium from giving up its own. The process of galvanic corrosion effectively corrodes the zinc before it gets to the aluminium. The zinc anode is sacrificed to save the aluminum.
As the zinc anodes become corroded they will need to be replaced or the corrosion will start working on the aluminum of your boat.
Don’t go gun-hoe and stick them everywhere as too many zinc anodes will cause the zinc to develop a crust which will cause the anodes to simply stop working.
If you plan to use paint as well as zinc anodes do not paint the anodes or grounding plates!
How to attach a hull zinc anode (video)
How to attach zinc anodes to the propeller shaft (video)
Attaching zinc anodes is not the only way to protect your aluminum boat from the corrosive effects of salt water.
There a variety of other ways to prevent corrosion on your aluminium boat.
Steps to prevent corrosion
Below are some steps you can take to further prevent corrosion on your boat.
- Wash your boat thoroughly after you’ve used it in saltwater.
- Ensure even the smallest of cracks and scratches are repaired before use.
- Cover anything that exposes the bare aluminum with aluminum paint.
- Don’t use an automotive battery charger on the boat.
- Do not exceed 1,300 millivolts of impressed voltage when protecting the aluminium.
- Don’t use mixed metals on the boat.
Protect your electrics too
It isn’t just the aluminum in your boat that is at risk from the corrosive effects of saltwater.
Be sure to protect your electrical wiring and fittings too with something like Corrosion X.
You can also use Corrosion X, or a similar product, to protect your fishing rods and other onboard metal-based accessories.