In-depth | PAINTS
Tere are a few methods available in the
- 100% transparent (all data available, no hidden or secret calculations)
- must be measuring hull performance and not fuel performance
- must be based on automatically logged data and not a selection of “good “ data
Fuel performance is important when
fuel cost and emissions are calculated, but not when we want measure the effect of
market for analysing fuel performance, but few, if any measure and analyse hull performance. To reduce fuel consumption and subsequent emissions, fuel performance is of course the prime focus, but the largest gain to this is achieved by improving the hull performance. There is an average 15% fuel improvement opportunity [3] in the improvement of hull performance by better antifouling coatings. Tis potential is available also to the existing fleet of vessels, offering the majority of the short term global fuel savings possible. However, in order to quantify and avoid more adaptive marketing efforts, there is a need for a global standard in hull performance measurement. Such a standard must be available to all and easily understood for the parties involved. Such a standard should aim to be:
initiatives implemented to improve the hull performance.
Conclusion An illusion of fuel savings achievable from some antifouling coatings, especially the biocide free solutions, has been created. Without the insights into how antifouling coatings and biocide free products do perform it is difficult to assess what is correct or not. We have tried to cover some of the basics in this article, but the question to ask when fuel saving promises are made would be; “fuel savings compared to what?” As a supplier of underwater hull fouling
protection systems we have an obligation to offer the customers our performance evaluation of the proposed solution(s) and offer similar advice when solutions are suggested by our customers. Te customer and the supplier’s expectations should be aligned. Another key learning point would be
that when fuel savings are promised and guaranteed, the analysis/proof should be based on operational data between the dockings and NOT including the benefits of surface pre-treatment in the docking procedures.
DNV set to appraise Jotun monitoring system
Norwegian class society Det Norske Veritas (DNV) will begin its evaluation of the Jotun monitoring system that will evaluate whether the company’s silyl methacrylate SeaQuantum X200 coating will sustain a maximum of 4.5% increase in fuel consumption or no more than a 1.5% speed loss over a five-year dry-docking interval. So confident are Jotun that its system will work that they have offered a money-back guarantee to owners if their ships fail to meet these efficiency levels. One observer believes, perhaps somewhat cynically, that Jotun are under pressure as their products come at a higher price than some of its main competitors and that the company, therefore, “struggles to sell it products”, hence the guarantee.
DNV will evaluate the product over the summer months said Giermund Vage, Service director of Asset Risk Management, “We need to understand the technology,” he said. Mr Vage added that the Jotun system collected essential data from monitors on the engine, showing the power used, a measurement of speed through the water and other data such as weather and currents and this information is then analysed using methodology developed by Jotun. “To approve the system we need a standard and then we must assess the system’s accuracy,” explained Mr Vage. Jotun’s monitoring system essentially collects data from the propeller shaft and the speed of the vessel through water. By measuring the torque and rpm of the shaft and using the Doppler log to measure the speed through the water the system effectively by-passes any other effects, such as current and wind speeds. Bjørn Wallentin, global sales director - hull performance solutions for Jotun, explains: “We must first know what the theoretical power to speed ratio is, as supplied by the newbuilding yard, and then we look for variations that will show whether the hull or propeller is fouling”.
The company has tested the method on 15 ships of a variety of types, including bulk carriers, tankers, ro-ro ships, container ships and LNG carriers and the system has proved to be accurate to within ±0.3 – 0.4% said Mr Wallentin and most vessels already have the measuring equipment on board, though a data monitor would need to be added to collect enough information for the system to achieve the accuracy required.
20 The Naval Architect July/August 2011
Further, if indexes are the way forward,
we should aim for one’s that reflect true performance not theoretically possible performance. This because the biggest potential in reducing fuel consumption and emissions lies within the existing fleet of vessels – incentives to reduce their carbon foot print by using higher quality antifouling coatings, proven by a fully transparent hull performance method, would have immediate positive financial and environmental effects. There is clearly a need for a standard
method for analysing hull performance. Jotun has developed such a method, but are open for constructive feedback and questions from all interested parties to help fine tune the collection and analysis methods. Please visit our HPS web site to learn more about it:
www.jotun.com/hps. NA
1
ICS, 2009. Shipping, World Trade and the Reduction of CO2
Emissions. International
Chamber of Shipping, London, UK. 2
IMO, 2009. Interim Guidelines on the
Method of Calculation of the Energy Efficiency Design Index for New Ships. Circular MEPC.1/Circ.681. International Maritime
Organization, London, UK.3 3
IMO, MEPC59/INF.10, Prevention of air pollution from ships, page 236
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