Industry is being readied for a safe, efficient and environmentally sustainable cleaning standard
Shipowners’ association BIMCO is leading an industry working group to formulate global standards for hull and propeller cleaning. Besides BIMCO, the group includes stakeholders such as paint manufacturers, companies that offer cleaning services, as well as ports. The industry-wide standards will set out how to evaluate the effectiveness of hull and propeller cleaning, how to handle cleaning products and seawater discharge, as well as a permitting process for companies that offer cleaning services. The standards will also describe shipboard documentation of the cleaning regime adopted by the ship.
There is an industry need for greater availability of hull and propeller cleaning, says HullWiper general manager Laurance Langdon, pointing to the increased stress on fuel efficiency as part of efforts to cut greenhouse gas emissions. “In addition, countries such as Australia and New Zealand are saying that ships coming into their ports are demonstrably ‘clean’, ie, free of invasive species,” Mr Langdon adds.
In the absence of a global standard, the options for in-water hull and propeller cleaning are divided between parts of the world where there is a more relaxed approach to these issues, such as in Asia, and ports where stringent standards are in place, such as in Europe. Some European ports, such as Southampton and Gothenburg, have qualified companies performing hull and propeller cleaning, following a rigorous scrutiny of their processes.
Ecosubsea is one of the approved vendors in Southampton. The company chief executive officer, Tor M Østervold, says cleaning is performed using a battery-operated submarine; adding a soft jet ensures that none of the painting is scraped out during the cleaning process and no metals are released. “When cleaning is underway, substantial volumes of seawater from the cleaning are pumped to the surface where they are filtered in several steps and then discharged to the sea. The biological material is diligently collected and becomes feedstock for biodiesel at a nearby plant in Southampton,” adds Mr Østervold. Mr Østervold is aware of the BIMCO standards and believes that very soon there will be a rapid increase in the number of ports allowing hull and propeller cleaning services.
Before cleaning takes place, there must be an assessment of the accumulation of anti-fouling. According to AkzoNobel’s diagnostic manager Dr Adam Bell this in itself can be challenging. Traditionally, AkzoNobel has worked with diving companies that send human divers to perform ship hull inspections. However, relying on human divers for inspections has posed other kinds of challenges, including diver safety, permitting by port authorities and sea conditions.
Due to these constraints, Dr Bell and his team began researching ways to optimise visual inspections of vessels’ hulls using unmanned technologies. The team’s research led them to micro remotely operated vehicles (ROVs) which can be deployed by one operator to collect video footage of the state of a vessel’s hull. The footage provides the requisite data for the visual inspection and the whole process can be completed in under one hour from the safety of dry land.
Based on Dr Bell’s success, AkzoNobel has acquired several SeaDrone Inspector 3 ROVs to perform ship hull inspections. Dr Bell’s team teches AkzoNobel technical service representatives (TSRs) to perform coating inspections using the SeaDrone Inspector 3 ROVs, and these TSRs have since become the company’s front-line customer service representatives.
New on the market
Hempel has launched a new coating system, which incorporates advanced anti-biofouling properties. Hempaguard MaX is applied in three layers, meaning it can be applied more quickly, reducing time in drydock by up to two days. Hempel’s head of marine group product management, Davide Ippolito, said: "Fuel savings and hull protection are achieved due to the low average hull roughness level delivered by the whole coating system, very low speed loss over the entire operational period and improved anticorrosive capabilities. Hempaguard MaX exploits the synergies between its three different layers: Hempaprime Immerse 900, tie-coat Nexus II, and Hempaguard X8.
The topcoat Hempaguard X8 is built on Hempel’s Actiguard technology. This coating combines the smoothness of a silicone coating with an improved hydrogel microlayer and an active ingredient to improve antifouling performance. Hempaprime Immerse 900 and Nexus II contribute significantly to Hempaguard MaX’s low AHR. A smoother hull delivers less drag and improved fuel efficiency. Hempaprime Immerse 900 is an anticorrosive primer that can be applied in one coat, while Nexus II is a tie-coat technology with improved anticorrosive capabilities.
Hempel has also introduced a coating that should be suitable for tankers operating as storage and those slow steaming. Globic 7000 is a new antifouling coating with enhanced operational flexibility for all tanker types and a speed loss of 4.5% on average according to ISO 19030. The operational flexibility stems from the biocide mix to guard against both hard and soft fouling, which improves the performance against slime and algae, and makes Globic 7000 suitable for wide operational conditions, including slow steaming and long idle periods, says the company.
According to Hempel, patented microfibres increase the coating’s resistance to abrasion and impact damage often incurred during daily operations; they also protect against cracking and peeling.
Tankers that undergo long periods of storage duties in the Middle East often have topsides painted white to reduce heat absorption, which can lead to heating of the cargo and cargo loss through evaporation. However, white topsides are difficult to keep clean and the glare off the white deck can be hazardous underway. Nippon Paint Marine offers a solution to these issues in the shape of Ever Cool, a dark paint that behaves like a white paint. Requiring no special application tools or processes, Nippon Paint Marine uses advanced formulated reflective pigments to prevent surface temperature increases and lower heat transfer through steel plate and other structures.
Field tests carried out over six months took place on the deck above a vessel’s wheelhouse. Measuring some 4,379 different points, the sensors registered no solar reflecting effects during the low temperature months of January and February, but when the mercury began to rise from March, “We noticed a huge amount of solar reflectance,” said Nippon Paint Marine (Europe) director Olaf Töbke.
Where a conventional grey polyurethane coat had a deck surface temperature of 71°C, the grey coloured Ever Cool was 23°C cooler. Ever Cool in green had a temperature of 51°C against the 64°C of a similar coloured epoxy. Red coloured polyurethane and epoxy-coated decks each had a surface temperature of 71°C, while the red coloured Ever Cool was 54°C.
Explaining Ever Cool’s potential in reducing newbuild and operational costs, Mr Töbke said: “By reducing the surface temperatures of exposed decks, shipbuilders can reduce the insulation requirement, while ship operators can reduce the air conditioning/chiller load, saving fuel and improving the onboard conditions for passengers and crew, especially in tropical climates.”