You’re standing before a beautiful yacht, gazing at her stunning lines, commending the great design, but while the design has been paramount for the features, less glamorous aspects like metal fabrication and paint application are fundamental to bring it forward. Surely you have noticed the colour or combination of different hues and shades, yet the application of filler and paint preparation are pivotal especially in metal structures in complimenting those lines, bringing them to shine. And it is a very laborious process, spanning over one third of the whole build, accounting for 5-10% of the total cost and needs to be repeated on right intervals. When a yacht spends most of her time in warm regions like the Mediterranean or Caribbean, it requires new application between 4 to 6 years and in colder climates, like northern Europe, renewal is necessitated every 8 years. Paint is a main feature throughout a yacht’s life and needs to be paid the same attention, but how does it rank in respect of environmental attitudes?
Metal structure, whether it is steel or aluminium, comes with building tolerances. There are small deformations introduced during forming and welding on the plate that are translated to peaks and troughs that need to be smoothened out with filler. In a composite structure the end surface comes from a mould and is smoother, requiring less post work. Filler is applied throughout the vessel and varies in thickness, to compensate for the hidden irregularities and provides a faired end result. Up to the 1980s, asbestos was an integral part of filler, yet the composition changed upon the revelations of the carcinogenic attributes of asbestos and new elements were used. In practical terms, the industry developed alternatives and when the Hong Kong convention was introduced, fillers could be given the approved status without any further consideration.
Hardly was filler the only component that has gone under extensive transformation due to its adverse impact on the environment. The underwater hull of the ship requires a special type of paint, anti-fouling, that is limiting the marine growth onto its surface, which could be introducing micro-organisms to new geographical areas, adding to the friction of the ship and increasing fuel consumption. In the early days, substances like mercury were used, later replaced from organotin, yet by now both are listed as dangerous to the underwater life. Organotin is simply excluded from all paints, while there is a very small percentage still permissible for mercury.
Top coat hasn’t been free of regulatory restrictions, as lead has been included in the past for its anti-corrosive characteristics. Lead specifically has been quite popular on onshore structures, for example houses and it is still permitted at acceptable, low values. Even the latest revelations of the negative effects of cadmium has been answered from the industry, despite restrictions been introduced relatively recently, in 2015. In general, all materials used for the whole paint application, including reducers and converters, have been so prepared and meet the Hong Kong convention, while still maintaining a high end product.
A slightly sore point in the whole paint process remains its preparation and more specifically blasting. A new build, where the steel used is relatively new, can be prepared with only sanding or local grinding, scrapping by hand. It is indeed a tedious stage, that has significant consequences on the outcome, yet it is not detrimental to the environment. In the renewal of paint though, blasting is required and regardless whether it is dry or wet, it poses hazards for the people working with it and the environment, without proper facilities and procedures. Facilities have to be so designed that ventilation is adequate to remove particles from the interior efficiently, the floors are impermeable and there should water / waste containment system to control the release of hazardous elements. When grit is used, arrangements have to be made in order to collect it, separate it and reuse it. Similar processes have to be followed for containing and cleaning the water and collecting what needs to be sent to waste management facilities.
Grit blasting is still the most effective method, but it is producing more waste than, for example, hydro-blasting. The latter though, apart of lower quality, is also more expensive and personally I would prefer to steer industrial practices away from water, as its resources are also depleted in a fast pace. In summation, indeed blasting is critical, yet can be in line with the environment.
What fascinates me in regards to the painting industry, is its adaptability. It was among the first industries targeted for their hazardous substances and practices, but every time the key players, manufacturers and applicators, created new materials and methods environmentally friendlier, without sacrificing quality standards for their product. They’ve constantly evolved to give the best in the market. Other disciplines in the yachting industry can actually gain a lot by adopting this attitude, i.e. engine manufacturers focusing in different energy storage solutions, rather than investing in different fossil fuel.