As a designer, I have met friends who prefer to entrust themselves to a steel sailboat project instead of an aluminum one.
Can I use my aluminum boat in saltwater? Yes, but you have to precautions on all the things mentioned below.
Why are they being aluminum longer life, lighter, and ideal for balancing this type of boat? The answer is listed below.
The aluminum boat has many problems with galvanic saltwater corrosion.
Let’s study! Let’s make a brief synthesis to inform ourselves and lose the fear of this spectacular material.
Can I Use My Aluminum Boat In Saltwater?
Also called electrolytic or cathodic, it is the deterioration of the material due to an electromechanical reaction, where an “anode” metal deteriorates (loses material).
It is by generating a flow of ions to another “cathode” metal, both submerged in an electrolyte (fresh or saltwater).
If we connect them outside the electrolyte, we can see the difference in potential and current between them.
Brackish water stands out due to its slightly higher salt content than freshwater. Unlike freshwater, it is not drinkable. Although it does not have such a high salt content as saltwater, zinc anodes are usually used in brackish water. The use of aluminum anodes is also possible.
According to its name, saltwater has the highest salt content. Like salty water, it is inedible and has the best electrochemical conductivity.
This property makes saltwater the most dangerous type of water because it is the fastest place for corrosion. Zinc anodes use in saltwater.
To his boat both in the inland waterways and be able to use it carefree, our experts recommend using sacrificial anodes made of aluminum.
The metal of these sacrificial anodes has a high potential difference and is typically used, as already described, in freshwater or brackish water, which has low electrical conductivity.
Nevertheless, these anodes can be used in salt water without any problems, since saltwater has an excellent electrical conductivity anyway.
How is anodic aluminum? Of course, up to here, we have only understood why the fear generates, but it is easy to protect our boat is in easy steps.
Surface Painting for Aluminum Boat In Saltwater
For there to be galvanic current, both metals must have contact with the electrolyte (water).
Aluminum is a good conductor, but if we paint the helmet with epoxy, we are already protecting most of its surface, which will not be in contact with water.
It is important not to paint aluminum helmets with copper-based antifouling, since it does not isolate, and also copper would cause electrolytic corrosion with aluminum.
The deck and cockpit and, if possible, the bilge should be well insulated. The concept is: Any place where rainwater or seawater can accumulate must be well painted and insulated.
Install Sacrificial Anodes For an Aluminum Bass Boat in Saltwater
- Install zinc (for saltwater) or magnesium (for freshwater) anodes.
- To know if the sizes and quantities of anodes installed are correct, we must do the potential reference test
- Set up a multimeter in the range of 2 Volts
- Connect the positive of the multimeter to the helmet
- Connect the sacrificial anode to the helmet and the positive of the multimeter
- Connect the multimeter negative to a silver-silver chloride reference electrode.
- Check the measurement – according to the attached table, for an aluminum helmet; the measurement should be between 0.90 and 1.10 V.
- If the aluminum overprotects, it could form a white alkaline chemical corrosion.
Install A Voltmeter For Best Aluminum For Salt Water
Install a voltmeter on the control panel, connecting one pole to the helmet and the other to the reference electrode.
Thus, a constant reading will obtain, being able to know if the boat is protected or not.
Isolate The Ground For My Aluminum Boat In Saltwater
The alternating current circuit’s grounding must be very well insulated from the hull on all metal boats.
In this way, we avoid having a connection with the metals of other ships or with the metals of the marina.
A “galvanic isolator” can also install, isolating the earth connection using diodes if it detects current.
Care And Cleaning of Aluminum Boat
To keep an anode clean and to match it to the well-groomed exterior of the metal to be protected, you can clean it in different ways.
A wire brush is a good helper here. It can remove algae, oxides, and other residues (e.g., fats, oils) from the sacrificial anode.
The bristles should be made of stainless steel or brass to avoid rust when using the brush and the associated loss of hair.
A rust-free bristle material also prevents rust particle transfer from the bristle to the anode or the ship.
Another method of caring for sacrificial anodes is using a sandblasting gun.
Due to the pressure of the sandblasting gun and the fine structure of the sand grains escaping from it, residues of any kind can remove very reliably.
Global Isolation For Best Aluminum For Salt Water
There are two things to isolate on an aluminum boat:
- Metal Isolation: If we decide to isolate the different metals of the boat concerning the hull, we will have to place anodes on each submerged metal to protect them, and the issue will resolve. This concept is widely used on fiberglass boats, but on metal boats, it is more difficult: it implies that the hulls, engine legs, axle line, coupling stain, and rudder shaft will have to be isolated and other elements.
- DC Circuit Isolation: To avoid stray currents from the battery bank, this circuit must be isolated. (Eddy currents are electrical currents that escape its conductive circuit to use another as a conductor, for example, the helmet.) A pure current of 1 mA can cause a lot of corrosion in a year. The circuit must be isolated from the mask; for this, I recommend making a neat and insulated negative terminal block, or at a reasonable distance from the hull; identifying each negative cable is also correct after installation. Although the sound continuity test of the multimeter verifies that there is no continuity.
Voltage Insulation Test
Turn on all thermal or electromagnetic keys on the control panel and turn off all appliances
Set the multimeter to direct current range 20mV; the negative to the negative of the battery and the positive to the helmet There should be no voltage
If there is a voltage, disconnect all the images from the terminal board, and connect one by one, checking the lack of insulation
Now connect the positive to the positive of the battery and the negative to the helmet with all the keys on. There should be no voltage
If there is voltage, it must be switched off-key by key until identifying where the problem is in boats.
Cathode Protection For Boats
It is about protecting the steel with zinc anodes, as we have already pointed out.
Zinc anodes use to extend further the life of steel structures submerged in seawater, such as steel pylons, boats, metal floats, etc.
Aluminum elements, in contact with wet steel, are also exposed to galvanic corrosion.
Avoid Corrosion Of The Outboard Motor In Saltwater
Regardless of where you moor your boat, corrosion attacks on both the inside and outside of your outboard motor often occur every day.
Sometimes you can see it with the naked eye, but sometimes you can’t. Even rainwater can have corrosive effects that can be detrimental to the outboard motor.
Corrosion can occur virtually anywhere on the outboard motor inside, in the fuel system or internal cooling water lines, and outdoors at various electrical connections and exposed metal components.
Wash Outboard Motor After Use Boat in Saltwater
All fresh or saltwater contains contaminants that eventually accumulate in the cooling ducts over time.
Also, saltwater is naturally corrosive, and any remnants in those cooling water passages after use can increase corrosion.
Saltwater can also undergo crystallization when exposed to temperatures above 170 degrees, causing deposits that restrict cooling water passages.
For these reasons, it is imperative that you thoroughly rinse your engine with clean, fresh water after each use.
Resistivity Test For Boat
- The main key in the OFF position
- Turn on all the keys of the circuit
- The multimeter should be in Ohms position range 0-100; connect the multimeter’s positive to the positive of the battery, the negative of the multimeter to the helmet (see figure, left), and measure.
- Connect the positive of the multimeter to the negative of the battery, the negative of the multimeter to the helmet, and measure
The reading will read as follows:
- Ten kOhms indicates that the resistivity is acceptable, that is, there are no eddy currents
- From 1 to 10, kOhms demonstrates that there is some eddy current, but it is not direct. It can even cause by the conductivity of the bilge’s humid air
- <1 kOhm indicates serious losses with severe damage to the hull. Turn off each key to identify the troubled driver or artifact – commonly found in engine ignition connections.
At the end of with a short paragraph Can I use my aluminum boat in saltwater? Still, the answer is yes for questions buy you need the above all precautions.