Securing Gas Tanks In Aluminum Boats: A Guide

Aluminium fuel tanks are a common feature in boats, but they need to be properly installed and secured to avoid corrosion and leakage. The key to preventing corrosion is to ensure that the aluminium has adequate airflow and does not trap water. This can be achieved by using materials such as plastic and stainless steel, and avoiding materials like wood and rubber that can trap moisture and cause corrosion. One method for securing an aluminium fuel tank involves gluing the tank to the deck using 3M 5200 adhesive and plastic strips. This creates a strong seal and suction that can withstand the weight of the fuel. Another option is to use a strap system, such as nylon straps or commercial truck straps, to secure the tank in place. Proper installation and regular inspection of aluminium fuel tanks are crucial to ensure the safety and longevity of the boat.

Avoid corrosion by using well-made thick aluminium tanks

Aluminium boats are corrosion-resistant but not corrosion-proof, especially if low-grade aluminium is used. Corrosion is caused by a combination of water and dissimilar metals, which leads to a galvanic reaction. This is known as galvanic corrosion and is more prevalent in saltwater, but it can also occur in freshwater.

To avoid corrosion, it is important to use well-made, thick aluminium tanks. Aluminium is self-protecting as long as its surface gets adequate air exposure. Severe corrosion occurs when water is present and there is a lack of oxygen, so it is important to eliminate any points that may trap water. This is known as crevice corrosion.

When installing an aluminium tank, it is important to avoid using wood, rubber, or any water-absorbent material as these can trap water and cause corrosion. Instead, use high-density plastic strips to support the tank. These should be glued to the tank with a strong adhesive, such as 3M 5200, to ensure there are no gaps or crevices for water to enter.

Additionally, only use stainless steel pipe fittings for the fuel supply and avoid mixing metals. Make sure the tank is installed on a stable surface, such as the hull stringers, and not the bottom of the hull. By following these steps and choosing well-made, thick aluminium tanks, you can effectively avoid corrosion in your aluminium boat.

Ensure proper ventilation to avoid fume build-up

Proper ventilation is essential to avoid fume build-up and ensure the safety of your boat. Gasoline fumes can accumulate in the bilge area, posing a fire or explosion risk. Here are some detailed instructions to ensure proper ventilation:

Firstly, understand the regulations. Inboard gasoline boats built after July 31st, 1981, must have a mechanical ventilation system according to US Coast Guard regulations. This system includes components like exhaust ducts, which extend from the bilge area to the open air, and intake ducts that allow fresh air to replace the trapped fumes.

The ventilation system should have two parts: an air inlet and a separate air outlet. These ducts should be positioned above the bilge line and in the lower portion of the compartment, as gases tend to accumulate near the floor. The intake duct should be placed to catch moving air, while the exhaust duct should be located higher to allow warm air and fumes to escape naturally.

Regularly inspect and maintain your ventilation system. Check for blockages or damage in the ducts, and test the bilge blower periodically to ensure it is functioning correctly. Keep the engine compartment clean to ensure the ventilation system operates efficiently.

Additionally, consider using gas fume detectors, which provide early warnings of fume buildup. Place these detectors in enclosed compartments and check their batteries and sensors frequently.

By following these instructions, you can ensure proper ventilation and avoid fume build-up, maintaining the safety of your boat and everyone on board.

Use stainless steel pipe fittings to avoid galvanic corrosion

When installing an aluminium fuel tank in a boat, it is important to consider the materials used for the tank's pipe fittings. Using stainless steel pipe fittings can help to avoid galvanic corrosion, which occurs when dissimilar metals are used in close proximity, especially when touching.

Galvanic corrosion, also known as bimetallic corrosion or dissimilar metal corrosion, happens when two dissimilar metals are coupled in the presence of an electrolyte, such as saltwater. In this process, one metal, the anode, corrodes faster than it would alone, while the other, the cathode, corrodes slower. Stainless steel is a good choice for pipe fittings because it is highly resistant to corrosion and has a long lifespan.

To prevent galvanic corrosion when using stainless steel pipe fittings, it is important to avoid mixing stainless steel with other metals in the same plumbing system. This includes not only the pipes themselves but also fasteners, hangers, bolts, and screws. Even a single screw made of a dissimilar metal can cause accelerated corrosion around it. If different metals must be used, they should be separated by insulating materials or dielectric unions.

Additionally, care should be taken during installation to prevent damage to the surfaces of the fittings. This includes avoiding dropping or dragging them on rough surfaces, as scratches or dents may compromise the corrosion resistance of the material. It is also important to keep the fittings clean and free from contaminants such as dust, dirt, and other foreign particles, as these can contribute to corrosion. Tools made from materials compatible with stainless steel should be used to prevent cross-contamination and damage.

Secure the tank with straps or glue

When securing a gas tank in an aluminium boat, it is important to remember that the problems with aluminium tanks are usually due to improper installation, rather than the material itself. Properly installed, aluminium tanks will usually outlast the life of the boat.

Using Straps

One way to secure a gas tank in an aluminium boat is by using straps. You can use a gas tank tie-down kit, which usually comes with straps, loops, and screws. The straps are placed across the tank, and the kit is designed to fit most fuel tanks. Make sure the straps are well-constructed and wide enough to securely hold the tank in place.

Using Glue

Another way to secure a gas tank is by gluing it in place. One recommended method is to use 3M 5200 adhesive to glue plastic strips to the bottom of the tank. First, cut the plastic strips to the appropriate length and width, and then apply the adhesive to the entire surface of the plastic strips. Press the strips into position, ensuring that the ends are equally spaced from the edges of the tank. Wipe off any excess adhesive and allow it to set for 24 hours. Once the adhesive has set, apply two beads of adhesive along the length of each plastic strip. Carefully set the tank into place, making sure it is straight. The adhesive will create a strong suction that will hold the tank securely in place.

Avoid trapping water between the tank and the boat

To avoid trapping water between the gas tank and the boat, it is important to understand how water gets into the fuel tank in the first place. Water can enter the tank through condensation, especially if the tank is only partially filled. Humid air enters the tank through the fuel vent, and moisture is absorbed into the fuel as the air expands and contracts with temperature changes.

To prevent this, keep the fuel tank topped off. Additionally, ensure that the fuel filler cap is in good condition and securely sealed. Inspect and replace the cap if it is faulty or worn to prevent rainwater, seawater, or water from washing the boat from entering the tank.

It is also important to be mindful of the materials used in the tank's installation. Avoid using wood or rubber, as these materials can trap water and cause corrosion. Instead, opt for high-density plastic strips to secure the tank. These strips should be cut to the width of the tank, leaving no room for water to collect at the edges. Use an adhesive to attach the strips to the tank, ensuring that there are no gaps or crevices for water to enter.

Finally, consider using fuel additives designed to absorb and remove water from the fuel system. These can be used as a preventative measure or to address existing water contamination.

Frequently asked questions