When it comes to ships, the first things that come to mind for most people might be their huge hulls and roaring engines. However, few people notice that there is an "invisible guardian" on the hull of a ship - ship paint. This seemingly ordinary "coat" actually conceals a lot of knowledge, enabling ships to navigate "healthily" in the complex Marine environment.

I. The "Superpower" of Marine Coatings: Why Can't Ships Do Without Them?

The Marine environment can cause considerable damage to ships: high salt content in seawater can corrode the metal of the hull. Barnacles, oysters and other creatures in the sea like to attach to the bottom of ships, increasing the resistance of navigation. Sunlight and waves can also wear down the appearance of the hull. And Marine coatings were developed precisely to address these issues, mainly featuring three "superpowers" :

Anti-corrosion: Dress the hull in a "metal protective suit"

Most hulls are made of steel, and seawater will slowly "cut" the steel like "small scissors" (that is, electrochemical corrosion). Anti-corrosion coatings contain components such as zinc powder and chromate, which can form a dense protective film on the metal surface, preventing seawater from coming into contact with steel. It is just like wrapping the hull with a "waterproof and anti-corrosion film", extending the hull's service life by 10 to 20 years.

Anti-biofouling: Turning the bottom of the ship into a "slippery no-passenger zone"

Once barnacles or seaweed attach to the bottom of a ship, it will increase the ship's navigation resistance by 20% to 30% and consume 10% more fuel each year. Anti-biological coatings contain special components (such as organotin used before, but now copper-based compounds are used for environmental protection), which can slowly release "repelling signals", keeping Marine life at bay, maintaining a smooth bottom of the ship, and reducing fuel consumption.

Drag reduction and energy conservation: Installing "invisible thrusters" on ships

Some high-end ship coatings (such as fluorocarbon coatings) have very smooth surfaces, which can reduce the frictional resistance between seawater and the hull. Data shows that ships coated with drag-reducing paint can save 5% to 8% of fuel annually, which is equivalent to a 100,000-ton cargo ship saving several million yuan in fuel costs each year.

Ii. "Division of Labor in Ship Coatings: Different Parts Wear Different 'Outerwear'

Just as we wear cotton-padded jackets in winter and T-shirts in summer, the coatings on different parts of ships also have their "exclusive roles", mainly divided into three categories:

Ship bottom coatings: The "Underwater Guardian" of anti-corrosion and anti-biological properties

The bottom of the ship is constantly submerged in the sea, so the coating must have both anti-corrosion and anti-biofilm adhesion functions, and also be wear-resistant (after all, it will encounter seabed sand and mud). The common bottom coating for ships is a combination of "epoxy asphalt anti-corrosion coating + copper-based anti-biological coating". First, an anti-corrosion base coat is applied, followed by an anti-biological surface layer.

Hull coating: "Outdoor Sun-protective Clothing" resistant to sun and weather

The hull (the part of the ship above the water surface) is exposed to sunlight, rain and waves, and needs to be "sun-proof and scratch-resistant". This type of coating is mostly acrylic resin coating, and its color is mostly white or light blue (which can reflect sunlight and reduce the heat absorption of the hull). It can not only resist ultraviolet aging but also keep the appearance of the hull bright and not fade for several years.

Deck paint: Anti-slip and wear-resistant "underfoot safety mat"

There are people walking and goods piled up on the deck, so the paint must be anti-slip, wear-resistant and resistant to seawater erosion. Deck coatings are usually epoxy anti-slip coatings, with quartz sand and other particles added to increase surface friction. Even if the deck gets wet from seawater, people walking on it are less likely to slip.

Iii. New Trends in Marine Coatings: More Environmentally Friendly and Smarter

With increasingly strict environmental protection requirements, ship coatings are also "upgrading and evolving", and two new directions have emerged:

Environmental protection: Say Goodbye to "Toxic Components"

Previously, organotin was commonly used in anti-biological coatings, which would pollute the Marine environment. Now, it has been banned globally. Nowadays, the mainstream is "low-VOC (volatile organic compounds) coatings", with VOC content over 50% lower than that of traditional coatings. They do not release harmful gases and are more friendly to Marine life and the health of seafarers.

Intelligence: Capable of "self-repair" and "alarm"

Scientists are still developing "smart coatings" : for instance, self-healing coatings with microcapsules added. Once small cracks appear in the coating, the microcapsules will automatically break and release repair agents to fill the cracks. There are also "sensor coatings" that can monitor corrosion. If corrosion begins inside the hull, the coating will change color or send out electrical signals to alert the crew to repair it in time.

In fact, although ship coatings may seem insignificant, they are the "hidden heroes" of the shipping industry. It not only safeguards the safety of ships, but also helps shipping companies save costs and reduce pollution. The next time you see a ship, why not pay more attention to this "special coat"? It is precisely this that enables huge ships to sail safely on the sea