15 Feb 2022
Marine Biofouling on vessel hulls is believed to add approximately 110 million tons of excess carbon emissions annually across the shipping industry. With around 90 000 ships sailing ocean waters and transporting nearly 90 percent of world trade, vessels not only emit a significant amount of GHG emissions but also carry and release other ecologically harmful pollutants along its voyage.
Biofouling has been pinpointed as a weighty challenge for the maritime world as commercial trade has a direct impact on the health of marine life and the environment. With ships sailing from port to port, vessel hulls collect a variety of barnacles, algae and other aquatic organisms. This results in cross-pollination, where foreign marine species are released into waters that is not their natural habitat, thereby threatening local oceanic fauna and flora.
According to research conducted by the international environmental organisation The Clean Shipping Coalition, biofouling can add up to $30 billion to shipping's annual bunker fuel bill as the heavy drag of IAS (invasive aquatic species) on vessel hulls increases fuel consumption. Biofouling can also cause significant maintenance issues for vessels and reduce overall performance.
While the substantial increase in fuel consumption has a negative impact on a vessel's bottom line, it's the introduction of these invasive species into new environments through a ship's hull that has been identified as the biggest threat to the ecological well-being of the planet.
The industry may contribute toward a significant portion of the global climate change problem, but it continues to work hard to mitigate its impact through a range of solutions. One such solution is regular hull cleaning which offers ship owners and operators the opportunity to improve the energy efficiency, speed and longevity of vessels.
Why hull cleaning is important
To compensate for the frictional resistance caused by biofouling, and to keep to schedule, ships are forced to increase power resulting in increased fuel consumption and carbon emissions. An effective way for vessel operators to increase energy efficiency and reduce fuel and carbon emissions is through regular vessel hull cleaning. Frequent hull cleaning removes biofouling growth and lowers the risk of invasive species polluting local port waters and outnumbering native species.
Here are a few ways the industry is fighting biofouling:
Antifouling coating is a type of specialised paint that is applied to vessel hulls to help prevent the growth of marine organisms on vessel structures. These paints contain specific chemicals that prevent organisms from settling on surfaces and continues to play a vital role in decreasing the commercial and operational costs of the maritime industry.
The coating also serves as a corrosion barrier for the hull. This inhibits the deterioration of the metal and helps prevent costly steel repairs. While this may be an effective method to keep a ship's hull clean, a coat of fresh antifouling paint is not enough to prevent biofouling build up.
Manual hull cleaning
This cleaning method involves the direct removal of marine fouling by divers through the use of cloths, brushes or scraping devices. However, this common cleaning practice can have a negative effect on oceanic ecosystems as it is often impossible for divers to remove and collect all of the invasive aquatic species that accumulate. Nearly 40% of the species remain attached to a ship hull, even after cleaning and some removed debris is released into the ocean. This along with the plastics from the cleaning brushes that get introduced to the water column. The safety of divers is also put at risk as we know they can be disorientated under the vessel leading to panic and the primary cause of diver deaths during hull cleaning is the use of SCUBA (best saved for holidays not professional divers).
Traditional Brush/Kart method
Traditional underwater hull cleaning is a method known as the brush-kart system. Qualified divers utilise high-powered brushes that clamp down on the hull and dislodge the thick sludge of biofilm that has collected along a vessel's journey. This process offers no form of filtration as removed marine organisms contaminate local port waters and abrasive bristles damage expensive antifouling paint and of course more plastics from the cleaning brushes that get introduced to the water column.
Stepping into the future with HullWiper
Green and innovative hull cleaning technology has proven to be the most effective method to align with the shipping industry’s environmental goals. There are a number of companies taking hull cleaning into the 22nd Century, and we are just one of that number.
HullWiper is, we say, at the forefront of this sustainable move toward eco-friendly solutions with its Remotely Operated Vehicle (ROV). The diver and brush-free ROV does not require divers, harsh chemicals or abrasive methods and cleaning can be performed day or night, in most weather conditions and whilst cargo or bunker fuels operations are underway. Fouling is removed by utilising high-pressure seawater jets and all removed fouling is collected onboard the unit’s filter system for safe disposal onshore. HullWiper cleans 96-97% of submerged areas faster than traditional cleaning methods with a cleaning impact that lasts 2 - 3 times longer.
Choosing the right hull cleaning solution can help ship operators save money, time and, most importantly, the environment.