Ecospeed Allows Non-Toxic Fouling Control on Underwater Ship Hulls

By MarEx 2012-02-27 16:22:30

There is currently no hull coating available which will not foul. The only way to remove this fouling is by cleaning it off. Like it or not, ship hull cleaning is an essential part of operating a vessel or a fleet efficiently and economically. Any level of fouling, including biofilm or slime, carries with it a considerable fuel penalty. With current fuel prices, this is too much to ignore.

If a ship is to sail clean then the cleaning must be 100%. It takes longer and therefore costs more. However, this extra time and money is more than recovered since the ship operates with a clean hull, thus benefiting from the maximum fuel savings. It is also the way to prevent the spread of non-indigenous species (NIS) and thus avoid falling “foul” of the increasingly tight regulations on this subject. Finally, along with regular cleaning goes regular inspection of sea chests and other nooks and crannies so that the ship can be kept in top running condition and any problems can be predicted and avoided.

In most circumstances, the best and most viable approach is to clean the ship 100% and to do so regularly and always before sailing if the ship has been stationary for a long enough period to have become fouled.

And ship hulls must be protected with a system which lends itself to fast, effective underwater cleaning without risk of damage to the coating and without posing any kind of hazard to the environment.

The need for efficient and environmentally safe fouling control

There are a number of important reasons for the shipping industry to lean towards a more efficient and environmentally safe approach to hull coating and fouling control. The current financial climate and the growing concern for the environment have made these factors harder and harder to ignore.

  • Rising cost of fuel. The price of bunker fuel has been rising and all indications are that it will continue to do so. This is a major concern for all shipowners/operators who are looking for ways to reduce this cost so that they can maintain a profit margin without having to raise their prices excessively. Therefore keeping a ship’s hull in smooth condition and free even of slime can add up to savings as high as 20% or more.
  • Pressure to safeguard the marine environment from the harmful effects of chemical biocides contained in conventional antifouling paints. This is a valid concern. The trend here is towards a complete ban on biocides in hull coatings where there is any doubt about the environmental safety of these biocides. So far no biocide has been developed which is completely safe environmentally. Already many ports in the world understandably ban the underwater cleaning of hulls coated with biocidal AF paint in order to protect their waters and environment.
  • The problem of accumulating pollution and contamination of ports and harbors and their immediate surroundings, along with the great difficulty of dredging or trying to clean up those areas.
  • Rising concern about harmful atmospheric emissions of the so-called green house gases (GHG). Harmful emissions go hand in hand with fuel consumption. These emissions tend to be in direct proportion to the amount of fuel burned by ships. Propulsive fuel consumption can be reduced in a number of ways. A major factor is avoiding the extra fuel required to overcome the hull friction increase caused by hull coating deterioration and fouling. Reduce fuel consumption by maintaining a smooth hull and removing slime and other biofouling in a timely manner and this will automatically reduce the emissions of atmospheric pollutants.
  • Efforts to limit the spread of invasive non-indigenous species (NIS) via ship hull fouling. Greater and greater pressure is being exerted to prevent or limit the spread of invasive non-indigenous species (NIS) via shipping, both from ship hull fouling and from ballast tanks. The only effective way to eliminate the spread of NIS is to clean a ship’s hull thoroughly before it leaves one environmental zone to go to another. The only hull coating which can be cleaned successfully is a hard coating, including surface treated coatings such as Ecospeed.
  • The economic need to extend the interval between drydockings. Many operations to the underwater hull and other parts of the ship below the water line can be accomplished more quickly and economically with the ship still afloat, without pulling the vessel out of the water in drydock. The pressure to drydock vessels less frequently and for shorter periods of time so as to keep costs down is increasing. This can be clearly seen in the push towards a 7.5 or even 10 year drydocking interval. The main obstacles to this extended interval are hull corrosion and fouling. The main incentive, if these factors are handled, is a great reduction in costs.

These six factors are all driving the industry in the same direction: use of a hard, inert, non-toxic coating and routine in-water cleaning. This is where Ecospeed comes in. Ecospeed is a hard, inert, specially-formulated glassflake vinylester resin surface treated coating system that includes routine underwater cleaning without the risk of chemical pollution to the environment or of damage to the coating. Ecospeed can be cleaned aggressively and rapidly and will only improve in smoothness with each cleaning.

The benefits of underwater cleaning on Ecospeed

1. Ecospeed improves with each underwater treatment

One of the many unique factors of this underwater hull coating system is that with repeated underwater hull cleaning, the coating’s surface aspect does not degrade but gradually improves.

This procedure is made easy by the coating’s technical properties. Cleaning can be carried out whenever needed, at any point in its lifespan, without causing damage.

Regular underwater cleaning of the coating results in improved hull smoothness each and every time the hull is cleaned. The coating will maintain its integrity at all times. 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 any increase in fuel consumption over the years as would happen with traditional, active antifouling paints which are known to degrade steadily over time. The ship hull can be kept close to its optimum hydrodynamic condition thereby producing major fuel savings.

2. Long lay-up periods have no effect on the condition of the Ecospeed coating

As a consequence of the current economic climate, more and more ship owners are forced to lay one or more of their ships up for longer periods. For some types of ships (military ships are a good example) the normal pattern of operation sometimes includes lengthy lay-ups followed by rapid mobilization. This has, however, no adverse effect on an Ecospeed coating which can always be restored to its optimum condition, regardless of how much fouling has attached itself to the hull while the vessel has been laying idle. Cleaning a severely fouled hull is more time consuming and expensive than cleaning a lightly fouled ship, and it is probably better policy, especially if fast mobilization is required, to clean the hull often enough to keep the fouling to a more manageable level, even if the vessel is out of service.

Ecospeed is ideally suited for ships which have a stationary period because an impermeable barrier is created during application. This gives the coating its excellent and durable anti-corrosive properties and protects the underwater hull against mechanical damage. Despite the aggressive nature of certain types of fouling, no rust or damage to the steel will be present on the underwater hull of the vessel after cleaning. The hard fouling is unable to penetrate or damage the glassflake vinylester coating.

This is illustrated by a cruise ship that remained stationary in the Caribbean for seven months after it was coated with Ecospeed. After this period the coating’s qualities allowed a complete removal of all fouling from the underwater hull of the vessel during an underwater cleaning without causing any damage to the underlying paint layer which was restored to its original pristine condition.

3. TBT-free, copper-free, biocide-free and silicone oil free solution

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.

As part of the tests, comprehensive sampling was performed at the start, during and after the underwater cleaning of several ships. These samples were then examined, and the results verified that there is no impact on the water as a result of the underwater maintenance, even in close proximity to the cleaning unit used. Because the water in the ports could have affected the tests and to verify the results, additional tests were performed in a lab in worst case scenario circumstances which led to the same conclusions.

Examination of the samples showed that only marine fouling is removed during the cleaning process and that the Ecospeed coating stays intact and has no effect on its surroundings.

4. The solution to the NIS problem

The underwater cleaning of Ecospeed can be regarded as a safe measure that prevents, rather than remedies, the spread of NIS. Firstly, Ecospeed can be cleaned on a regular basis without damaging the coating’s surface. The cleaning interval is optimized to minimize fouling and the associated increase in fuel consumption. In other words, regular cleaning prevents heavy fouling from occurring and at the same time presents an opportunity to inspect so-called niche areas. Secondly, Ecospeed is a very durable coating that withstands abrasive cleaning for which very effective specialized tools have been developed. As a result, many of the fouling organisms will be destroyed during cleaning.

5. Underwater cleanings on Ecospeed allowed

After the submission of the experimental results of aforementioned EU-LIFE demonstration project to port authorities and environmental agencies worldwide, several major ports have already overturned the existing general ban on underwater hull cleaning, specifically making an exception for vessels coated with Ecospeed.

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 the cleaning of AF paints. Ships moored in ports continue to leach biocides, which leads to accumulation in sediments. The Dutch Ministry of Transport, Public Works and Water Management proactively sought a solution to this environmental problem. It came to the conclusion that a good non-toxic ship hull coating 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.

6. Specially designed equipment used by trained divers

Underwater maintenance of Ecospeed is carried out with specially designed underwater hull cleaning tools that simultaneously remove all fouling and optimize the smoothness of the paint surface.

A complete set of complementary equipment was designed in-house to allow divers to clean the flat areas as well as the harder to reach parts of the hull without damaging the coating.  Sea chests and other nooks and crannies are best cleaned out using underwater high pressure water jet equipment. This combination makes it possible to have a 100% clean hull after each maintenance session, resulting in the best possible hydrodynamic condition of the underwater hull throughout the service life of the vessel and the removal of any potentially harmful invasive aquatic species which the ship may have picked up.

The Hydrex R&D department is constantly working on ways to improve the available underwater cleaning equipment even further. New versions of the tools are regularly put into practice to achieve an even faster cleaning rate without losing any of the quality.

Hydrex diver/technicians are specially trained to work with the latest versions of the underwater hull cleaning tools. This allows them to carry out underwater maintenance of the Ecospeed underwater hull coating in the shortest possible time frame. They are also trained to be flexible. The combination of these factors makes it very easy for them to adapt an underwater cleaning operation to the schedule of a ship.

7. Less drydockings required, less time in drydock needed
Over the last couple of years there has been a trend of extending the maximum drydock interval from five to seven and a half years. Several large classification societies already allow this extension, but only if a stringent set of rules is followed.

One of the requirements is the execution of a very strict preventative or semi-preventative underwater maintenance plan. Ecospeed’s qualities make the coating ideally suited for such a regime. Regular underwater cleaning, removing any marine fouling at a very early stage, will maintain and improve the ideal surface characteristics. This benefits the hydrodynamics of the vessel throughout its service life and helps avoid any risk of spreading NIS.

Besides helping owners to make their ships eligible for a lengthening of the drydock interval, it also gives them the opportunity to take all the hull maintenance steps needed to reduce fuel consumption outside of drydock. The use of Ecospeed on hulls opens the door to looking deeper into how to optimize fuel efficiency in between dockings. Hydrex can help owners with this by monitoring the condition of the ship hull, propeller, rudder and other parts of the underwater ship through detailed in-water inspections. Based upon these findings a tailor-made maintenance program can be set up. This, combined with Ecospeed’s performance-enhancing benefits, enables owners to optimize the hulls and thus the fuel efficiency of their vessels.

Ecospeed can, however, also be cleaned with high pressure tools in drydock, which is the standard practice when a ship enters drydock. It is done 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 dirty red water filled with toxins and the antifouling paint chips spreading everywhere. With Ecospeed, none of the paint material is lost. 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.

Summary

Ecospeed is a hard glassflake vinylester resin coating that can be cleaned underwater without any risk of chemical pollution to the environment or of damage to the coating. Ecospeed can be cleaned aggressively and rapidly and will only improve in smoothness with each cleaning. Underwater maintenance of Ecospeed can be regarded as a safety measure that prevents, rather than remedies, the spread of NIS. For these reasons several economically important ports have already overturned the existing general ban on underwater hull cleaning, specifically making an exception for vessels coated with Ecospeed.

Ecospeed’s qualities also make the coating ideally suited for the very strict preventative underwater maintenance plan that is part of the requirements to extend a vessel’s drydock interval to 7.5 years.

Underwater maintenance of Ecospeed is carried out with in-house designed underwater hull cleaning equipment by specially trained Hydrex diver/technicians. This allows them to clean the flat areas as well as the harder to reach parts of the hull without damaging the coating.