Protecting Your Aluminum Boat's Hull: A Comprehensive Guide

Aluminum boats are known for their strength and durability, but their bottoms can be susceptible to scratches and damage from rocks and other debris. To ensure the longevity of your boat and avoid costly repairs, it is essential to protect the bottom of your aluminum boat. In this article, we will discuss several ways to achieve this, including regular cleaning, applying protective coatings, using boat bottom paint, installing keel guards, and staying cautious while boating. By following these tips, you can maintain the value and performance of your boat while enjoying your time on the water.

Use a protective coating like Alumetron

Protecting the bottom of an aluminium boat is essential, and one way to do this is by using a protective coating like Alumetron. Alumetron is a clear polymer coating that protects aluminium boats from corrosion, tarnish, staining, pitting, salt spray, and other environmental damage. It is a long-lasting solution that can keep your boat's hull looking shiny and new for up to 10 years.

Alumetron is unique because it chemically and mechanically bonds with aluminium, making it superior to other coatings. It fills in the fissures in the aluminium, creating a smooth finish that is less susceptible to dirt and marine growth. This protective coating is also water-based, environmentally friendly, and safe for the boat and the person applying it.

To apply Alumetron, start by cleaning and degreasing the aluminium surface with a product like Boat Clean Plus, ensuring there are no contaminants or pollutants that could impair the coating's adhesion. Rinse and dry the surface thoroughly.

Next, apply four thin coats of Alumetron, allowing each coat to dry completely before applying the next. This can be done by wiping the product onto the aluminium with a lint-free cloth pad, using long, even, overlapping strokes. Make sure not to overwork the application to avoid bubbles and streaking.

After applying the coats of Alumetron, allow it to cure for a minimum of 96 hours. You can then apply two coats of VS721, which will act as a fouling release coating and provide additional protection and ease of maintenance.

By following these steps and using Alumetron, you can effectively protect the bottom of your aluminium boat, ensuring its longevity and maintaining its shiny appearance.

Apply boat bottom paint

Applying bottom paint to your aluminium boat is a great way to protect the hull from corrosion and other damage. Here is a step-by-step guide to help you through the process:

Step 1: Prepare the Boat

Before applying bottom paint, it is essential to clean the hull thoroughly. Use a power washer, brush, or scraper to remove any loose paint, dirt, grease, or marine growth. It is crucial to ensure that the hull is entirely free of contaminants for the paint to adhere correctly.

Step 2: Sand the Hull

Lightly sand the hull with 80-grit sandpaper to create a smooth surface for the paint to adhere to. Be cautious not to sand through any barrier coat or damage the gelcoat of the hull. Wipe down the surface with a solvent wash after sanding to remove any residue.

Step 3: Choose the Right Bottom Paint

Select a bottom paint specifically designed for aluminium boats. Choose a paint that contains a compound of zinc, cuprous thiocyanate, or a non-metallic agent such as ECONEA™ as the biocide. Examples include Vivid, Trilux 33, ECO HRT, or Hydrocoat ECO.

Step 4: Prepare the Work Area

Cover the entire work area with a drop cloth or tarp to protect it from paint spills. Ensure adequate ventilation and wear protective gear, including a respirator, goggles, and gloves, as bottom paints can release toxic fumes.

Step 5: Apply the Bottom Paint

Follow the manufacturer's instructions for the chosen bottom paint. Typically, bottom paint is applied using a roller or brush. Start by stirring the paint thoroughly to ensure the copper is evenly distributed. Then, pour the paint into a paint tray and roll it onto the hull from one end of the boat to the other. Apply multiple thin coats rather than one thick coat for the best results.

Step 6: Allow Drying Time

Refer to the manufacturer's recommendations for drying time between coats and before relaunching the boat. Drying times can vary depending on the type of paint used and environmental conditions.

Step 7: Clean Up

Once the paint is dry, remove all masking tape and clean up the area. Properly dispose of any leftover paint and solvents used for clean-up according to local regulations.

By following these steps, you can effectively apply bottom paint to your aluminium boat, providing a protective barrier against corrosion and other damage, ensuring the longevity of your vessel.

Install a keel guard

Keel guards are a cheap and effective way to protect the bottom of your aluminium boat. They are a great way to reinforce the areas of your boat that are vulnerable to dents and scrapes from abrasive surfaces like sand, rocks, and gravel. Keel guards are usually self-adhesive strips that can be applied easily and quickly to any cleaned and primed keel area.

• Ensure Compatibility: Not all keel guards are compatible with all aluminium boats. Check with the manufacturer to confirm if their product will work with your boat's hull design. Some keel guards require a smooth hull surface without sharp angles or rivets, while others can accommodate protruding keel bones.
• Prepare the Keel Guard: To make the keel guard material more flexible and easier to work with, lay it out in direct, warm sunlight for about 30 minutes. You can also use a hairdryer to achieve the same effect.
• Surface Preparation: It is important to prepare the surface of your boat's keel for optimal adhesion. Follow the manufacturer's instructions for cleaning and priming the keel area. This may include etching the surface with a Scotch-Brite pad or fine-grit sandpaper to remove dirt, wax, and mould release agents.
• Apply the Keel Guard: Carefully apply the keel guard to the prepared surface, ensuring it adheres smoothly and securely. Follow the manufacturer's instructions for proper placement and any specific recommendations for your boat's make and model.
• Seal the Edges: Once the keel guard is installed, use a marine-grade sealant along the leading and trailing edges, especially around any uneven areas or gaps near the keel. This will help ensure that no water can work its way underneath the adhesive.
• Maintenance: Regular maintenance will help keep your keel guard in good condition. Wipe it down with a clean towel after each use and inspect it for any areas of concern. Seal any small gaps where water could penetrate with a marine-grade adhesive sealant.

By following these steps, you can effectively install a keel guard on your aluminium boat, providing a layer of protection against scratches, dents, and corrosion.

Regularly clean the bottom

Keeping the bottom of your aluminium boat clean is one of the simplest ways to protect it. Rinse the bottom of the boat with fresh water after each use to remove any salt, dirt, or other debris that may have accumulated. Regular cleaning will also reduce the growth of algae and barnacles, which can cause damage to the bottom of the boat over time.

If you're in salt water, it's especially important to clean the bottom of your boat to prevent corrosion. You can use a product like Algex to remove marine growth and surface corrosion, or Boat Clean Plus to remove salt, dirt, and grime.

To keep your aluminium boat in good condition, it's important to establish a regular cleaning routine. This includes inspecting, cleaning, and drying your boat after each use. Storing your boat in an area away from direct sunlight will also help to protect the hull from premature ageing.

In addition to fresh water rinses, you may also need to give the bottom of your boat a more thorough cleaning from time to time. This could involve scrubbing with a brush or using a pressure washer to remove any built-up grime.

By maintaining a clean boat bottom, you'll not only improve the appearance of your boat but also extend its lifespan and avoid costly repairs.

Use galvanic anodes to slow saltwater corrosion

Sacrificial Anodes, or Galvanic Anodes, are an effective way to protect the bottom of an aluminum boat from saltwater corrosion. These small blocks of metal are designed to be attached to any metal boat hull.

The anodes work by gradually eroding as their more active voltage metal interacts electrochemically with metal ions in the water. This process prevents a similar reaction from happening to the hull of the boat.

To maintain the protective effects of galvanic anodes, they must be replaced at regular intervals as they do corrode quickly. It is also important to keep them free from any coating, including paint and protective sprays.

When selecting an anode, it is important to consider the type of water the boat will be used in. Zinc is the most common material used and is suitable for saltwater applications. However, it is not effective in freshwater and will stop working after a few months if not made to millimeter specifications. Aluminum alloy anodes are a better option as they provide more protection and last longer than zinc, working in both saltwater and freshwater environments. Magnesium anodes are the most active metal on the galvanic scale and should only be used in freshwater. They can cause overprotection and damage the hull in saltwater or brackish water.

In addition to selecting the appropriate anode material, it is important to consider the size and weight of the anodes. The surface area of the anodes determines the amount of protection they provide, while the weight determines how long they will last.

By using galvanic anodes and following the recommended maintenance and replacement schedule, boat owners can effectively slow saltwater corrosion and protect the bottom of their aluminum boats.

Frequently asked questions