Ever wonder why vessels are painted red below the waterline?

There are plenty of references on the internet, but if we page through history it all starts during the early days of shipping when most of the ships used to be made out of wood. Wood, being an organic material, had a very porous structure. The combination of slow ship speeds and rough hul surfaces proved to be the ideal breading ground for underwater sea life, seaweeds, barnacles as well as marine worms.

The marine contaminants had a profound effect on the speed of the ship. Damages suffered by the hull due to the growth of marine organisms increased the weight of the ship, increasing drag. Therefor, ship speeds were also effected considerably. Shipbuilders urgently needed something to counter the immense outgrowth of marine life at the bottom of the hull. This made way for antifouling, an extremely important concern for modern ship builders and maritime bodies worldwide.

Antifouling is the science of designing. materials as well as coatings to combat the growth of marine life on any submerged body.

The earliest methods included the installation of copper sheets on the ship’s hull. The main reason behind the use of copper sheet was to stop marine organisms, particularly worms, from making their way to the wooden hull.

However, instead of copper sheets, we use specialised paints on marine vessels, known as ‘antifouling paint’. This paint works on the same principle as copper sheets. SEAP GRANDPRIX 660 HS is a tin free antifouling paint with self polishing action in service and long protection against marine organisms.

Copper oxide has a reddish tinge, thus giving the paint its famous red colour. That is why vessels are painted red below the waterline.

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