Importance of paint on ships

The painting of a boat when it is in the dry dock does not only have a decorative function. It is necessary for the protection of the boat and to extend its life. In addition, before applying the boat hull paint, it is essential to carry out a priming process, which protects it better than the usual paint, which will determine the colour.

 

Why is it necessary to paint ships?

Periodically carrying out the process of priming and painting the boat is not only advantageous, but necessary. The process has these functions:

• It makes the boat easier to clean and safer to navigate.
• It creates a film between the surface of the hull and the environment, protecting it.
• Anti-corrosion boat paint protects metal hulls against corrosion.
• Prevents osmosis.
• Prevents wood from rotting and drying out.
• It prevents encrustation of underwater areas, which can slow the ship’s progress and damage the hull.

 

 

Classification of paint types

The boat is always painted with several coats of different types of paint, which must be applied in the correct order. These are listed below, starting from the innermost layer of paint to the outermost.

Primer

The primer or sealer is the first product to be applied after cleaning. Its function is to protect the hull and serves as a base for the other coats of paint. It also prevents water damage to fibreglass and wooden hulls. In the case of metal hulls, it protects them from corrosion.

Nautical primers can be divided into two types:

• One-component: These are synthetic and are sold ready to use, but are somewhat less durable.
• Two-component, such as polyurethane or epoxy primers. Epoxy is a product made from resins and is usually sold as two separate products: the base and the catalyst. They have to be mixed just before application, as once combined they harden quickly. However, these coatings have a higher resistance than single-component coatings.

Currently, epoxy is one of the most widely used primers, due to its high resistance.

 

Intermediate layers

The hull of the ship is divided into different zones, which are treated differently:

• Hull or hull skin: Part of the hull that is immersed in the water.
• Topside: Area of the hull above the waterline. It is usually the most weather-resistant, but is subject to the action of the sun.
• The engines.

A couple of coats of antifouling or patent paint are usually applied to the hull to prevent fouling and living organisms. On the topsides, an enamel or primer is used before painting the boat. The number of times this is done will depend on the manufacturer.

Various varnishes or paints with sunscreens can be applied to the engine covers. For outboard engines, an antifouling solution should be used, while for inboard engines it is better to use a specific enamel for engines.

 

Finishing paint

In addition to these paints, teak decks should also be protected with teak oil, which should be applied every three to four months to prevent them from turning grey.

On gel-coat decks it is advisable to apply an enamel with a sachet of anti-skid paint additive for boat decks.

 

One- and two-component paint

As you have seen, there are a single and two-component primer paints available. But which one to use?

One-component paints, e.g. one-component enamel or polyurethane, are quite traditional in yachting. Their advantage is that they are quick and easy to apply. However, some of these enamels can be somewhat soft, i.e. they are prone to damage from rubbing against moorings, fenders and other objects impacting the hull. Polyurethanes are not as susceptible to such rubbing, but have less gloss and sometimes fade when exposed to sunlight.

Two-component polyurethane marine paint is much more wear resistant than any one-component paint. Some, such as Awlgrip and Imronn, are harder than the gelcoat over which they are applied. Two-component paint tends to last longer than one-component paint; however, it is more expensive and more difficult to apply.

The two components must be mixed well, as they depend on a chemical reaction between them. It is very important to note that two-component paint (whether primer, undercoat or topcoat) cannot be applied over one-component paints, as its solvents will damage the existing coating.

Paint according to the resin

Depending on the base resin of which the paint is composed, it is possible to distinguish between oil-based, polyester, acrylic, vinyl, epoxy, polyurethane, alkyd, silicone, silicate, rubber, etc. paints.

Each of them has different properties and characteristics. For example, silicate-based paints are resistant to high temperatures and silicone-based paints are water-repellent.

 

Factors for better paint performance

How often a boat needs to be painted depends on many factors:

• The material of the boat (steel, wood, etc.) and its condition when painted.
• The environment (temperature, humidity, etc.).
• Tasks to be carried out on the ship.
• The quality of the paint.
• The type of paint and its combination with other paints.
• The weather conditions during painting, the way the operators work and the subsequent drying of the paint.

At Suisca Group we offer a primer and paint service for boat hulls. With more than 30 years of experience in the maritime sector, we will do a job with the best quality, so that the paint on your boat has the longest life possible. Leave your boat in the hands of an expert group!