Ecospeed Offers Solution for Protection of Underwater Hull

The underwater hull coating Ecospeed offers a TBT-free, copper free, biocide-free and silicone oil free solution for the protection of the underwater hull. The Ecospeed hull protection and performance system is today’s Best Available Technology for reduction of fuel consumption, GHG and other emissions through hull hydrodynamics and fouling control.

In 2008, stringent tests were carried out within the framework of an EU LIFE demonstration project to provide scientific data and to authenticate the non-toxicity of the Ecospeed hull performance technology. This research proved that the coating is 100% toxin-free and that there is no negative effect on the water quality or the marine environment at any point of its application or use. Moreover, the massive amounts of VOC and zinc anode emission associated with conventional hull coating systems are reduced to almost zero.

Over a 3.5 year period the objective of this project was to evaluate the environmental and economical benefits of Ecospeed as a biocide-free durable hull protection and antifouling system. The total economical impact was compared on several aspects including the application costs and increased fuel costs. It was then estimated for a 1000-TEU container vessel which was to have its Ecospeed coating regularly treated.

One of the first tasks within this project has been to validate that Ecospeed is completely free of biocides throughout its lifecycle. The Dutch Ministry of Infrastructure and the Environment carried out an elaborate study of effluent samples which has conclusively shown that no toxins are released at any stage, either at application, during curing or during in-water treatment. The measurements further showed that during cleaning only non-toxic fine particulate matter is released.

Fuel costs increase due to the added resistance characteristics of each coating system over time. Towing tank experiments have made it possible to estimate the inherent added drag levels, and the rate of increase over time is estimated roughly from data available in literature. Instead of increasing, Ecospeed’s resistance decreases as regular underwater treatment is used preventatively to keep added drag caused by marine fouling under control. Moreover at the same time it will improve its surface texture and hence increase its hydrodynamic efficiency. As a result, by adjusting the treatment interval, the increased fuel costs are minimized to significantly lower levels than would be the case for an SPC or foul release coating system.

When all the costs aspects are taken together, it is estimated that the overall economical impact of Ecospeed is about half that of an SPC and about three quarters that of a foul release for a 1000-TEU container vessel over 10 years.

On a global scale the potential for the reduction in fuel consumption and greenhouse gas emissions is enormous. The IMO currently estimates the annual fuel consumption by the world fleet at 310-350 million tonnes, implying an annual CO2 output of approximately 850 million – 1.1 billion tonnes. If 80% of the world fleet would switch from biocidal antifoulings to Ecospeed, this would save an estimated 28.5 million tonnes in annual fuel consumption and 90 million tonnes in annual CO2 output.

The project has shown that Ecospeed as a Surface Treated Coating is a valuable alternative technology to the biocidal copper based antifoulings that are currently on the market.

Getting rid of repeated environmental hazards

Ecospeed requires only two coats of 500 ?m each of the exact same paint applied to bare steel, aluminum or glass-reinforced plastic (GRP). No primer, no midcoat, no tiecoat, no topcoat are needed; just two coats forming a homogeneous protective coating. This is a major advantage compared with other hull coatings. If you reapply three to four layers of antifouling coating on the entire hull and are re-doing the above every three to five years, you inevitably come to a point where there are too many layers of coating on the ship’s hull. This will degrade the quality of the coating even more easily and rapidly because of the internal stresses being built up in the coating, resulting in a required full reblast, probably every ten years or so. This poses a big environmental hazard each time. Repeat applications mean repeated VOCs and repeated debris of the mess that results when the conventional coatings are removed.

Whether you are looking at classic antifouling coating systems or when comparing Ecospeed to some of the newer silicone based hull coatings, which also consist of four to five layers of different coatings to be applied, a two-coat homogeneous application is always going to be better for the environment.

The ban on underwater cleaning is lifted

Over the last several years, there have been concerns that non-indigenous species (NIS) are transported by fouled hulls just as much or even more than in ballast water. Once a hull becomes heavily fouled, a situation occurs where there is an increased risk of transporting NIS that needs to be remedied by defouling activities, either by out-of-water removal or by underwater cleaning. In this respect, underwater cleaning has come under some scrutiny out of fear that viable NIS are released and spread, rather than contained and disposed of by the operation. Several ports and countries have banned underwater cleaning out of concerns of pulse release of biocides and/or an increased risk of transferring NIS.

Another important outcome of the EU LIFE project was the submission of the experimental results to port authorities and environmental agencies worldwide in order to allow the underwater treatment of Ecospeed. The experimental results and the derived criteria for environmentally safe underwater cleaning have already convinced several economically important ports to overturn the ban. These ports recognize the negative impact of biocidal paints and want to support environmentally safe solutions.

The Netherlands was one of the first countries worldwide to practically ban the in-water cleaning of ship hulls in order to avoid the pulse release of TBT or other biocides associated with it. Ships moored in ports continue to leach biocides, which leads to accumulation in sediments. The Dutch Ministry of Transport, Public Works and Water Management has pro-actively sought a solution to this environmental problem. It has come to the conclusion that a good non-toxic system includes regular and controlled removal of fouling and that the underwater cleaning and conditioning of ships coated with Ecospeed is at present a Best Available Technology (BAT). Very strict criteria for environmentally safe in-water cleaning practices have been developed – criteria that only Ecospeed has been able to meet so far.

Easy and environmentally friendly fouling removal

Ecospeed makes further maintenance of the underwater hull very easy whether in-water or dry. Maintenance procedures can be repeated whenever needed during the vessel’s lifespan without causing damage to or deterioration in the quality of the coating’s surface and even significantly improving the coating’s hydrodynamic characteristics on each occasion. This will keep the hull as hydrodynamically smooth as possible, bringing about a major saving in fuel.

Underwater hull maintenance is carried out with specially designed underwater hull cleaning tools simultaneously cleaning as well as optimizing the smoothness of the Ecospeed coated surface. Regular underwater cleaning removing any marine fouling at a very early stage will maintain and improve the ideal surface characteristics. Tests have shown that a very large number (+500) of repeated underwater hull cleanings improves its surface texture without any adverse effects. This will prevent the major increase in fuel consumption over the years that occurs with traditional, active antifouling paints.

Ecospeed can also be cleaned with high pressure tools in drydock, which is the standard procedure for shipyards when a ship enters drydock to clear away any fouling and residues, especially salt residues that may adhere to the paint system. With Ecospeed the coating is always in a brand new, excellent condition after high pressure washing, requiring only minor touch-ups where mechanical damage has occurred. The surface texture is very smooth. The high pressure washing reveals without exception that Ecospeed does not need any additional paint layers and at most would require less than 1% touch-ups as long as the paint was standardly applied in the first place.

When washing an antifouling paint in drydock, the floor of the drydock is a complete mess, discolored with a dirty red water filled with toxins, and the antifouling paint spreading everywhere. With Ecospeed, none of the paint material is lost. It is clean water that you see. Only the fouling is removed. The coating stays on the ship instead of dispersing in the water and contaminating the shipyard and the surrounding waters.

Fuel savings reduce ecological impact tremendously

The emission of greenhouse gases (GHG) such as carbon dioxide (CO2) and nitrous oxides (NOx) as well as pollutants such as sulfur oxides (SOx) and particulate matter (PM) into the earth’s atmosphere by the burning of fossil fuels to drive ships is of increasing concern internationally.

While other aspects of ships and shipping play their own part in attempts to remedy this environmental concern, a key factor is the underwater ship hull. This is subject to biofouling, as micro-organisms and vegetable and animal matter naturally attach to a ship’s hull. A fouled hull carries with it a fuel penalty. The worse the fouling, the slower the ship will sail at a given RPM. Or, put another way, the more power will be required to keep the ship sailing at a given speed. This means higher fuel consumption. Depending on the degree of fouling, this can be as much as 85% more. Higher fuel consumption results in a greater volume of greenhouse gases and other emissions which pollute the earth’s atmosphere.

For this reason most ships sail with a chartering contract that includes a penalty clause if fixed distance/fuel consumption ratios are not met. However, the distance/fuel ratio is unpredictable with regular paint systems and will also worsen over the years. This is due to wear-down, uneven build-up of paint layers, corrosion and other damage which reduces the vessel’s performance and increases fuel consumption by as much as 25-40%, as shown by the dramatic improvement in performance when a traditionally coated hull is eventually blasted back to its original condition and recoated. In this way the ship becomes more expensive and profits are reduced. The distance/fuel consumption ratios set are seldom as high as the ship is capable of when the hull is hydrodynamically smooth. Meeting those contractual requirements does not mean the ship is sailing at optimum performance levels.

When using conventional paints, a vessel’s AHR (average hull roughness) will gradually increase as a result of the buildup of paint layers and the general deterioration of the paint system, causing increased fuel consumption. Whereas other coating schemes such as anti-fouling or silicone paints deteriorate substantially in between drydockings and the maintenance of them is limited to drydock only, the highly durable Ecospeed coating offers long-term fuel efficiency and lends itself to routine cleaning in the water. This keeps the ship’s performance stable and improving towards hydrodynamically smooth with progressive cleanings, protects the owner’s investment. A fixed distance/fuel ratio can be determined in advance and penalties are therefore avoided.

Because Ecospeed creates a smooth surface on the hull, the coating helps the ships glide more easily through the water. Since the engines do not have to be pushed as hard to get from one place to the next, several cruise vessels coated with Ecospeed have demonstrated that they can actually maintain their same cruising speed with reduced propulsion power. This helps to both save energy and conserve fuel.

In the chart below, the expected development of added fuel consumption over time for a biocidal antifouling is compared with three treatment scenarios for Ecospeed for one particular trading area. In the green scenario, Ecospeed undergoes an underwater treatment every six months. In the red scenario, the treatment interval is halved to three months; fouling will not occur as extensively and the associated added fuel consumption is limited.

Both scenarios show that with each treatment, effective cleaning restores the added fuel consumption benchmark observed at sea trials. The unique conditioning aspect that is carried out simultaneously with each cleaning optimizes the surface gradually over time, producing fuel savings with each treatment. In a third scenario, the best possible maintenance schedule is followed. As a result the fuel consumption observed will be lower from the very start and the smoother surface obtained prevents fouling from occurring as rapidly. The total savings in fuel consumption over the lifetime of a vessel is directly proportional to the area between the antifouling situation and the different Ecospeed scenarios.

Adjusting the frequency of underwater treatments allows an optimization of the vessel’s service speed and minimization of its fuel consumption.

Summary

Ecospeed is a TBT-free, copper free, biocide-free and silicone oil free solution. No toxins are released at any stage of its use including during curing or during in-water treatment. This makes Ecospeed at present a Best Available Technology (BAT) which surface texture improves with repeated underwater hull maintenance. Fuel consumption as well as GHG, VOC and zinc anode emission is thereby reduced. Ecospeed also allows owners to determine a fixed distance/fuel ratio in advance and avoid penalties.

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Source: hydrex, October 28, 2011