"It is important for a ship owner or ship manager to have a hyper-awareness of the relationship between type of coating and long-term fuel consumption," said Daniel Kane, vice president business development at Propulsion Dynamics Inc. The company has developed the CASPER hull efficiency computer program, which analyzes hull efficiency of ships by collecting performance data while it is making its voyage and conducts a hydro-dynamic comparison of the same type of data from sea trials.
"The results will show what penalty, in terms of speed and fuel consumption, the ship is suffering as compared to its voyage at sea trials when the vessel had the cleanest, smoothest hull," said Kane. "The analysis is performed on a continual basis with monthly reports submitted to the ship-owner, highlighting changes in resistance of the hull and propeller due to fouling."
The first, and arguably the most important step in hull maintenance, is choosing a marine coating. Selection of marine coatings should take into consideration the owners' and operators' expectations for service and life cycle costs.
When it comes to selecting a marine coating, according to Kane the old adage is true, "you get what you pay for." "When we compare ships that have used low-cost coatings to those that have used high cost coatings, the high cost coatings usually perform better," he added.
Regardless of vessel type, there are a number of key requirements that need to be addressed by both vessel operators and shipyards when selecting coating systems for newbuilding projects. "The selection of an anticorrosive coating can have a major impact on production and operating costs plus coatings must offer the correct balance of properties to optimize the return on investment for both parties," said Holger Ebbighausen, group communications manager coatings, Akzo Nobel. "The same is of course true for antifoulings and coatings used for repair and maintenance."
According to Hans Daems, group communications manager at SigmaKalon, there are a number of factors to consider when selecting a marine coating. These include substrate conditions, possibilities for substrate pre-treatment, lifetime expectancy of the coating system for the vessel, exposure conditions of those parts of the ship that are to be coated and local legislative requirements.
"Depending upon expectations, the proper maintenance and repair specification can be developed to assure the owner/operator is meeting their commercialization goals," said Eric Bosanac, director marine and offshore, The Sherwin-Williams Company. Deciding when to clean the hull–ideally before fouling has reached the level of barnacle growth–is critical. Once there is significant fouling growth on the ship's hull, wire brushes may need to be used to remove it, thus damaging the coating's integrity.
Another issue critical to ship owners is hull maintenance in drydock. Increasingly, in a bid to save money, there has been a move to decrease the lay-up/dry-docking times of both commercial and military equipment.
Kane cautions that it is tempting to reduce the cost of hull treatment in drydock, "however, in the long term, fuel efficiency will be compromised if the treatment in drydock is marginal."
"Time is money and requirements to assure equipment is operational and revenue producing is critical," said Bosanac. "Finally, we continue to hear about the lack of maintenance and repair and the subsequent causalities or near misses due to the lack of corrosion mitigations. This will become an ever important global marine topic with classification societies requiring more thorough inspections and repair."
In addition, raw material prices, local legislation splitting the global marine market into several local markets and increases in freight rates are all issues that postpone maintenance of vessels.
Another major issue affecting the marine coatings industry is environmental regulations. The ban on TBT has greatly affected the industry and will continue to do so for the foreseeable future as marine coatings companies continue to fine-tune TBT-replacement systems that are able to perform under some of the most challenging conditions.
"Although there are many solutions now available to address this issue, the consensus among owners and operators is that there has yet to appear technology that is comparable in performance to TBT-containing underwater hull coatings," said Bosanac. "This has produced a tremendous amount of development and research in the industry to find better solutions. Whether it be on the polymer, biocide or surface film/foul release characteristics, there is a great deal of research and development taking place. Unfortunately, much of this development work can not produce a quick resolution or determination of efficacy as the real life testing and performance must take place in the marine and offshore markets and not in the laboratory."
One of the major issues for marine coatings is the increase in regulations. "Especially the increasing demand on anti-fouling registration will have an enormous influence on the availability and pricing in this product group," said Rudi de Rijcke of Ameron BV. "Shortly, ballast tank coatings will be regulated through IMO. Also, shipyards are facing more stringent environmental legislation."
"Not just here in the U.S., but globally, regulatory restrictions will continue to play a role in the marine coatings industry," said Bosanac. "These regulations will look to continue to reduce volatile organic compounds (VOC) and restrict the use of those identified compounds known to be hazardous to applicators and the environment."
New Products and Technologies
Sherwin-Williams has been working closely with their customers to develop products that meet their requirements and demands. "For instance, standard marine alkyds have been used for decades, but we heard from our customers that they require better performance, better color and better gloss retention from their traditional alkyds," said Bosanac.
Sherwin-Williams' new Seaguard 1000 marine enamel provides exceptional performance when compared to standard solvent-based alkyds and oil-based topcoats, according to Bosanac. The company has also developed a new, universal anti-corrosive epoxy, which is ultra high solids, solvent-free and can be used for virtually every application in the new construction market. Sherplate 360 can be used for topside applications, as part of the underwater hull system and it also can be used in ballast tanks. "With a long overcoat binder and over two-hour pot life, this product will bring a better solution to the marketplace," Bosanac said.
Currently Ameron is working on a number of new technologies, including biocide-free antifoulings, metal-free antifoulings, ultra-durable topcoats based on novel resins and rapid-curing primers for rapid turnaround.
According to Daems, SigmaKalon is busy working on new technologies for use in future marine coatings, including waterborne silicate technology, high solid novolac epoxy systems, technologies to improve economical solutions for its customers and polyhydral oligomeric silsesquioxanes.
On the recreational/pleasure boat segment, color, ease of application and performance are the driving factors in choosing an antifouling coatings. Alumacoat SR and Alumaspray Plus from Pettit Marine Paint contains no tin or copper. Alumacoat SR and Alumaspray Plus work in both saltwater and freshwater to deliver protection against algae, barnacles and other marine fouling.