You were thinking of buying a new aluminum boat or thinking of using your old aluminum boat in saltwater and wondering whether it is safe to use an aluminum boat in saltwater or not? So, let’s find out whether using an aluminum boat in saltwater is safe or not?
Aluminum boats are safe to be used in saltwater; in fact, aluminum is known for its ability to resist corrosion well, but it can still corrode under certain circumstances. For boating in saltwater, extra maintenance is required for a boat; apart from that, using an aluminum boat in saltwater is Ok.
Saltwater is highly corrosive, and saltwater corrodes metal 5 times faster than freshwater. So saltwater effects the boat more than any other waters. But, it also depends on the organisms that grow in the water as well, not only due to saltness or something.
However, it is impossible to avoid corrosion altogether, but it is possible to prolong the process with the proper maintenance precautions such as washing the boat, flushing the outboard with fresh water after every ride, etc. And there is one added benefit with an “aluminum” boat.
Aluminum has a protective quality. When aluminum starts corroding, a thin coating of aluminum oxide forms on the surface, and it acts as a protective shield that inhibits further corrosion. Since saltwater is extremely corrosive, it takes some time, but eventually, the boat can corrode.
Although aluminum boats are corrosion-resistant, they are not corrosion-proof, especially if a low-grade aluminum is used. Luckily, there are various ways to prevent and protect the boat from the effects of oxidation and corrosion (go below for prevention tips).
Aluminum will react to saltwater, but it is a long process. In fact, aluminum is known for its ability to resist corrosion well, but it can corrode under certain circumstances. Unfortunately, exposure to saltwater can be one of those circumstances. It will take more time than normal boat corrosion.
The corrosion rate depends on so many factors such as the salinity of the water, temperature, organic material in the water, electrical activity nearby, presence of other metals, etc. Even growth on the hull will create conditions that make the aluminum more susceptible to corrosion.
Avoid the build-up of organic material, plant growth, algae, barnacles, etc. Keeping an aluminum boat for a long time in the water will form algae, barnacles, etc. on the hull. By not keeping the boat for a long time in salt water will reduce most of the problems.
Related post – Check my article on the Effects of saltwater on boats (link opens in a new tab) to know what parts of the boat will get affected by saltwater and prevention tips in a detailed manner.
Check this small video on how to protect an aluminum boat from saltwater. Meaning how to wash and clean the boat after every ride in saltwater thoroughly.
How long does it take to from corrosion on an aluminum boat if exposed to saltwater?
We will now see the effects of saltwater on an aluminum boat, but before that, we will see how long it takes to form corrosion on an aluminum boat?
Corrosion on an aluminum boat can take anywhere between 10 days to 1 month or 40 days to form. However, it depends on so many factors such as salinity, the presence of other metals, organisms, etc. So, 10 days to 30 days is an average measure; sometimes, it can occur quickly.
Aluminum is not found in the metallic state in nature; it is created from bauxite. Since the metallic state isn’t there naturally, aluminum is unstable. If it is exposed to the environment (saltwater or even salt air), it allows them (aluminum) to revert (go back) to their mineral form.
That whole (chemical) reaction is known as corrosion, and its result varies depending on the metal and the environmental factors acting on it. So, as I mentioned earlier, it depends on so many factors, such as salinity, the presence of other metals, electrical activity nearby, etc.
When saltwater comes into contact with aluminum, they can form both the chalky, white coating of aluminum oxide (which protects from corrosion) and unpleasant pitting. Fortunately, there are some easy ways to protect aluminum from saltwater and prevent unsightly corrosion.
If that chalky, white coating of aluminum oxide (which protects from corrosion) brakes due to electrolytic influences or anything (vibration, shock, or chaffing) can cause more severe and structurally damaging corrosion to the boat (then corrosion starts on the boat).
Some of the effects of saltwater on aluminum boats
- Corrosion problems – Corrosion is one of the main effects of saltwater on boats; saltwater corrodes metal 5 times faster than freshwater. But it is not only the saltwater’s effects on boats.
- Growth problems – Leaving a boat for a long time in the water will form a growth (algae, barnacles, etc.) on the boat hull. Forming algae or barnacles on the boat hull will take time (around a week or 10 days).
- Outboard problems – The outboard motor and the mounting (transom) also get affected due to saltwater and result in rust and growth (algae or barnacles) on the transom where the outboard is mounted.
- Check my article on How long can you leave a boat in the water (link opens in a new tab) to know how long can you leave a boat in all types of water (both saltwater and freshwater) along with algae, barnacles, blisters prevention tips.
Aluminum boat maintenance for saltwater uses
Now that you have understood some of the effects of saltwater on aluminum boats. We will now see some of the precautions you need to take to prevent corrosion on aluminum boats. After researching for hours, I came up with a recommended solution by many people and experts to prevent corrosion on aluminum boats.
Washing the boat with fresh water after every ride is only the highly recommended solution by experts to prevent corrosion on an aluminum boat hull. Washing the hull with hull cleaners also gives an additional assurance by removing all the dirt (salt) from the surface.
It’s easy to say “wash the boat and motor with fresh water,” but some essential steps are to be followed while washing and cleaning the boat with fresh water. We will now see all those things in a detailed way.
1. Wash and clean the boat with freshwater
Washing the hull of an aluminum boat is an essential step to do to prevent corrosion on the boat hull. A garden house will do an excellent job cleaning the boat. If you wash the boat once in a week or 5 days, it is highly recommended to use some of the cleaning products (hull cleaners) as well.
You can use Salt-Away (linked to Amazon) while cleaning the boat, and it removes salt, inhibits corrosion, and breaks apart salt accumulation on or inside the boat. You can connect the hose to the mixing unit (that you will get along with it) and start spraying it on the boat.
Give it a try if you haven’t till now. This product removes all the salt particles that are stuck on the boat inside the engine and forms a layer of a coat to prevent corrosion in the future. But, this product is only for cleaning the boat; it doesn’t remove any stains or bad spots on the boat hull.
You can use Star Brite Aluminum cleaner (linked to Amazon) to remove any spots on the boat hull, and it works very well for aluminum boats. It also removes the barnacle stains on the boat hull. First, spray it on the hull, leave it for some time, and then wiping the hull with any cloth is sufficient.
Washing and cleaning the boat with fresh water after every ride is an essential task to do to prevent corrosion on the boat hull if you go boating in saltwater. If you often clean the boat after every ride, you don’t even need any of those cleaning products; just washing with fresh water is sufficient.
2. Flush the outboard motor (if you have one)
If you have an outboard motor mounted on the boat, it is highly recommended to flush the outboard motor with fresh water after boating in saltwater. Since the motor intakes the water to cool down the entire system, salt particles in the water can stick on the motor’s interior walls.
If you don’t flush the outboard after every use, all those salt particles can corrode and make a hole on the motor’s interior walls. That will be an expensive repair. Flushing the outboard after every ride with fresh water will prevent all those things from happening and saves time and money.
Flushing muffs (linked to Amazon) do an excellent job in flushing the outboard, and just placing them on the air intake is sufficient, then connect the hose to the muffs and start pumping the water. Leave it for five minutes and turn off the water.
The freshwater alone may not remove all those salt particles inside the motor. So, it is highly recommended to flush the outboard motor with Salt-Away (linked to Amazon) to remove all the salt particles stuck inside the motor by breaking apart salt accumulation in your engine’s saltwater cooling system.
By doing those two tasks (Washing and cleaning the boat with fresh water and flushing the outboard motor) after every ride, you will completely prevent the risk of corrosion on the aluminum boat hull. After washing and flushing, let it sit some time to dry (essential step).
3. Bolts, electric hardware, and anode checks
Lastly, checking all the bolts, electric hardware, and anodes is also an essential task to do. Electronic hardware and bolts will get affected by saltwater. Make sure that all the wires are kept out of the saltwater. Bolts are also made up of metals that will corrode if exposed to saltwater for an extended period of time.
If you have a riveted hull, a regular check of those rivets is essential because each day, as the hull heats up, the metal will expand, followed by cooling at night. The rivets themselves will expand and contract differently than the rest of the hull.
You won’t notice anything right away, but over several years the rivet holes will begin to stretch and contort until they leak, and the rivets potentially fail. A welded hull or without rivets (assuming it was done properly) will last A LOT longer.
If it is a welded hull, it should hold up very well so long as you take care of it. If it’s only riveted, then the hull will not have nearly as long a life expectancy as welding hull. However, this can even be an issue in freshwater too. So, looking at those bolts and rivets regularly is also an essential task.
For electric hardware. Try to keep all the electric hardware at a far distance from the saltwater and use any lubricant to prevent damage. Otherwise, use marine graded electronic hardware.
For Bolts. To prevent corrosion on the bolts, apply lubricant or grease regularly. Saltwater corrodes metal 5 times faster than freshwater. So, it would be best if you were careful with all the metal parts on the boat.
For anodes. Check the anodes regularly. If they decayed more than half, replace them with new ones; otherwise, no need. Many people may suggest you to use anodes to prevent corrosion, especially for aluminum boats. They work well, but using extra ones may result in more negatives.
4. Use bottom paint (anti-fouling paint)
Applying anti-fouling paint will prolong the corrosion process to some extent. Due to the additional layer (anti-fouling paint) on the hull, aluminum will not get in contact with the water. So, it is a temporary diversion, and if the paint wears off, corrosion starts.
And don’t forget to check the hull regularly; if the paint wears off due to scratches on the hull or something, it needs to be addressed quickly; otherwise, they can provide a starting point for electrolysis. Regular inspection and reapplying the bottom paint at those spots is sufficient.
Some people may say that bottom paint is not needed for an aluminum boat. Still, it’s hard to conclude that because the corrosion and growth depend on so many factors like salinity, the presence of other metals, time taken, electrical activity nearby, etc., it’s good to be prepared in prior.
However, to play it safe, 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.” According to Boating mag.
Related post – Check my article on Why do boats need bottom paint (link opens in a new tab) to know what types of boats need a bottom paint in a detailed way and bottom paint benefits.
5. Do regular checks after every ride
Doing some regular checks after every ride, especially in salt water, will avoid most of the problems in advance. It’s easier to stop something happening in the first place than to repair the damage after it has happened (Prevention is better than cure).
- Watch for corrosion near bolt holes, chipped paint, behind peeling paint, and any place the aluminum has been scratched or dented. Edges, cracks places that trap saltwater are more susceptible than flat surfaces.
- Inspect the keel and corner castings regularly. If they have been dented or scratched on rocks or beaches, they may provide a starting point for electrolysis.
- If the paint wears off due to scratches on the hull or something, it needs to be addressed quickly; otherwise, they can provide a starting point for electrolysis. Regular inspection and reapplying the bottom paint at those spots is sufficient.
Doing regular checks after every ride and doing the appropriate job at that time will prevent all the problems in advance.
Key takeaways
Aluminum boats are safe to use in saltwater. The only problem with using an aluminum boat in saltwater is, it corrodes over time. Saltwater is highly corrosive, and saltwater corrodes metal 5 times faster than freshwater. So saltwater effects the boat more than any other waters.
However, it is impossible to avoid corrosion altogether, but it is possible to prolong the process with the proper maintenance precautions such as washing and cleaning the boat (hull) and flushing the outboard with fresh water after every ride.
Aluminum has a protective quality. When aluminum starts corroding, a thin coating of aluminum oxide forms on the surface, and it acts as a protective shield that inhibits further corrosion. Since saltwater is extremely corrosive, it takes some time, but eventually, the boat can corrode.
Luckily, there are various ways to prevent and protect the boat from the effects of oxidation and corrosion, such as washing the boat, flushing the motor, using zinc anodes, bottom painting, etc. Doing all those things in advance gives better protection for the aluminum boat.
Aluminum tries to resist it’s best to prevent corrosion, but aluminum is corrosion-resistant, they are not corrosion-proof, especially if a low-grade aluminum is used. So, as a boater, you need to complete the process by taking proper measures to secure an aluminum boat from corrosion, growth, etc.
Some useful products for aluminum boat hull maintenance in saltwater
Salt-Away (linked to Amazon). Salt-away works very well in removing salt particles that are stuck on the boat’s surface and inhibits corrosion and breaks apart salt accumulation on or inside the exhaust. You can connect a garden hose with it, and you can start spraying, and you can flush the outboard with it as well.
Starbrite Aluminum hull cleaner (linked to Amazon). This Starbrite hull cleaner will remove all the stains on the boat hull, and it also removes the barnacle’s stains on the aluminum hull well. Spraying it on the tough stains and wiping with a cloth after some time (5 min to 10 min) is sufficient.
