Efficiently treat your underwater hull for optimal protection

If you own a boat, you’ll know that maintenance never stops. One important part not to overlook here is treating the underwater hull. This part of your boat really takes a battering.

The underwater hull is always in contact with the water, be it fresh or salt. Without treatment, problems like osmosis, corrosion, or stubborn growth of algae, mussels, and more lurk. We’ll explain how to prevent that.

No boat can do without a proper underwater hull

The underwater hull is, in a sense, the foundation of your boat. We’re talking about the part of the hull that sits below the waterline. This makes it susceptible to damage. Think, for example, of micro-organisms attaching themselves to the coating, or corrosion if metal is exposed.

With a polyester hull, you can get blisters and moisture ingress in the gelcoat. This is better known as osmosis. With a steel vessel, rust formation and electrolysis are the culprits. Solutions include a robust paint system and good anti-fouling.

Why it’s important to look after your boat’s hull

If you’re not yet convinced why it’s so important to keep your boat’s hull in good condition, we’re happy to outline a few reasons. Proper treatment extends its lifespan. Without treatment, problems lurk.

Anti-fouling

If your boat’s in still or slow-moving water, you might find it gets covered in mussels, algae, and other sea life. Sometimes, this can even slow you down. A fresh coat of self-polishing anti-fouling could be the answer.

Protection against osmosis and blisters

With polyester boats, osmosis is also a potential problem. water penetrates the gelcoat and causes blisters which can eventually affect the ship’s structure. Prevent osmosis from developing by, for example, applying a protective coating.

Corrosion and rust protection

Rust is a constant worry on a steel yacht or any other metal boat. If left untreated, metal will eventually go, well, rusty. A fresh coat of paint or some epoxy will keep rust at bay and mean you get more joy out of your hull for longer.

Less fuel consumption

When your hull is spick and span, it automatically means less drag in the water. This allows you to reach higher speeds and use less fuel. When anti-fouling is applied correctly, this also saves you money.

Safety and reliability

If your hull has been compromised by osmosis, corrosion, or some other issue, it could put your safety at risk down the line. Regular attention to your underwater hull will ensure you can keep on sailing with complete peace of mind.

Keeping the value of your boat

A boat with an untidy hull loses value. A well-maintained boat without damage or scratches is more appealing to potential buyers. Therefore, keeping your hull in good condition is good for your boat’s value.

Hull maintenance plan

Tackling your boat’s hull yourself might sound like a bit of a chore. However, if you’re a handy sort of chap, with the right approach and a bit of time, you can get quite far.

Step 1: Jet wash and clean the boat

Take the boat out of the water using a boat lift and spray the hull clean with a high-pressure washer. Start at the waterline and work your way down. Remove algae, mussels, and other growth. For stubborn dirt, you can use a polyester or plastic cleaner.

Step 2: Inspect and check the hull

Carefully examine the hull. For fibreglass, check for bumps or blisters (osmosis), and for steel hulls, look for rust and corrosion. Also, inspect areas where the anti-fouling has worn off or is no longer adhering properly. Is the layer worn out? If so, use an anti-fouling remover to safely strip the old paint.

Step 3: Repair and fill minor damage

Right, if you spot any damage or rough patches, you’ll want to sort those out first. Fill any cracks and holes with an epoxy filler suitable for boats. Let that dry thoroughly, then sand the surface smooth again. That way, you’ll have a solid base layer.

Step 4: Degrease and dry the hull

Thoroughly degrease the hull and ensure it’s dust-free. This is crucial for the adhesion of new coats. Allow everything to dry properly before proceeding with primer or anti-fouling. With Impressed Pro degreasing wipes, you can be sure the surface is clean and ready for a new layer.

Step 5: Apply a new layer of the correct thickness

Apply the new coats of paint or anti-fouling. Usually, 2 coats of anti-fouling are sufficient, but with intensive use or saltwater, an extra coat is a good idea. Always observe the drying times specified by the manufacturer. For an extra smooth finish, you can spray the hull instead of rolling it.

Step 6: Regularly check your hull

After the treatment, it’s important to regularly inspect the hull. An annual anti-fouling treatment is usually sufficient. In the meantime, visually check for cracks, blisters, or early signs of rust, so you can tackle problems early.

Besides the hull, the through-hulls are also an important element of the underside of your boat. These are the openings through which pipes, drains, and cooling systems pass. Without proper sealing, water can get in here, and that’s not the intention.

For a proper seal, use sealant that is resistant to prolonged contact with both freshwater and saltwater. At AB Marine Service, we’ve had the best experience with Innotec’s Adheseal Marine.

Choose the right kit for your boat at AB Marine Service

The Adheseal Marine has fast skinning, fast curing, and high flexibility. It contains no solvents, meaning it won’t shrink or crack. It’s also isocyanate-free. It’s available in white, black, and brown.

Adheseal Marine by Innotec can be overpainted with virtually all modern paint and lacquer systems. It has strong adhesion to aluminium, steel, wood, stone, glass, concrete and most plastics. Therefore, it’s also a multi-purpose product.

Keep your hull in top condition for a long time

Giving the hull some attention might not be the most thrilling job, but it’s definitely important. It keeps the foundations of your boat shipshape and ensures you can enjoy many safe and confident trips on the water.

When using Adheseal Marine as a sealant, you’ll also make your hull fittings watertight. If you have any questions about treating your underwater hull or about our sealant, please don’t hesitate to get in touch. Our experts will be happy to help you.