Marine structures such as ship hulls need protection against corrosion and the attachment of marine organisms such as algae and barnacles, known as biofouling. Biofouling negatively affects the hydrodynamics of the hull, increasing drag and thus the necessary propulsive power. As well as increasing fuel costs up to 40% this also necessitates regular visits to shipyards for hull cleaning.
Antifouling coatings are a very effective and economic means of protecting ship hulls. However the predominant coatings are biocidal, using self-polishing co-polymers (spc) which gradually leach biocides by a chemical reaction to kill attached organisms. In 2001, the International Maritime Organisation (IMO) banned the use of paints containing TBT (tributyltin). Nevertheless, most antifouling paints still slowly release heavy metals and harmful biocides into the marine environment.
The leaching of copper into seawater from antifouling paints has been conservatively estimated at 5 000 tonnes per year. Studies have shown that these compounds persist in the water, killing sealife, polluting harbour bottoms and entering the food chain.
The main current alternative to biocidal antifoulings are foul-release coatings, which aim to prevent the settlement of fouling by providing a low-friction surface onto which organisms have difficulty attaching. These suffer from being soft and easily damaged, and reliant on sufficient speeds to remove weakly attached organisms.
The beneficiary, Hydrex, sought to demonstrate the effective prevention of fouling and corrosion from its totally new biocide-free antifouling and corrosion-prevention technology - Ecospeed. Ecospeed is composed of a vinyl ester resin which is reinforced with glass platelets. The glass platelets lie in different layers parallel to the substrate. As such, they form a very durable and impermeable protection layer, which is very effective for corrosion protection.
The ECOTEC-STC project aimed to show that its innovative antifouling paint and underwater maintenance concept would outperform existing anti-fouling techniques practically, economically and environmentally. Specifically, it aimed to prove the paint’s lifelong non-toxic properties and its avoidance of emissions of metal compounds to air and water during application and use. It further demonstrated that the use of the paint would reduce fuel consumption and prevent the need for repainting in dry dock with associated environmental and economic costs.
It sought to show these benefits on a range of vessel types and in the different waters of the Baltic and Mediterranean Seas and the Pacific and Atlantic Oceans.
The project ECOTEC-STC has shown that Ecospeed as a Surface Treated Coating is a valuable alternative technology to the antifoulings that are currently on the market. The greatest benefits come from its non-toxicity and long lifespan.
The project conducted supervised applications of the Ecospeed paint on seven vessels of various types: container vessels, general cargo vessels, an LPG tanker and a split hopper barge. Firstly, the surface was grit blasted and then Ecospeed was applied by airless spraying in two coats to a total dry film thickness of minimally 1 000 microns. The coating was found to cure rapidly and flooding was possible after 24 hours.
The vessels were sailed as normal and then checked, with impressive results. For example, a 1 000-TEU container that had spent two years in severe winter conditions in the Baltic Sea required only minor touch-ups for mechanical damage. The project concluded that the coating should provide anti-corrosion protection for the full lifetime of a standard ship - around 25 years.
Economically, the first application of Ecospeed is more expensive than alternative coatings. However, given that it does not need to be reapplied, just cleaned underwater, it is estimated that using Ecospeed would avoid around 50% and 33% respectively of the costs of using and reapplying an spc or foul-release treatment on an 1000-TEU container for 25 years.
The beneficiary estimates that, over 25 years, a copper-based spc treatment emits more than 23 times and a foul-release treatment nearly 13 times as many VOCs than Ecospeed. Tests found no evidence of toxicity from substances emitted by Ecospeed. The cleaning process also makes the surface more smooth and effective as an anti-fouling coating.
The project tested tools for the underwater treatment of Ecospeed and designed parameters to facilitate the process. It developed new and modified tools, including the use of remote operation. It also proposed criteria for environmentally safe underwater cleaning, including high regularity to avoid the transfer of non-indigenous species (NIS) to marine areas.
Although laboratory experiments found Ecospeed to exhibit 1.9% less drag than alternatives, investigations into the real impact found it impossible to separate the different at-sea variables. However, the beneficiary estimates that if 80% of the world fleet switched to Ecospeed, there would be an annual saving of 28.5 million tonnes of fuel and 90 million tonnes of CO2 - as well as 12 million litres of paint. Another benefit provided by Ecospeed to shipowners is that a ten year drydock interval can be achieved (instead of 3-5 years) which wouldmean a huge cost saving. This is highly important as in the near future, there will be a shortage of drydock space for larger vessels. Shipyards currently have a load factor of more then 85% to 95% and this does not leave much more room for expansion.
When all larger new built ships currently under construction become operational, ship owners will have difficulty to find dock spaces even for scheduled dry dockings. The ECOTEC-STC system allows vessels to stay out of drydock for ten years and longer with regards to the hull coating – a target never before achieved. The technical research team of the beneficiary is working on a concept which will also address the other parts of the vessel (i.e. rudders or propellers) that need to undergo maintenance before a ship can actually stay in the water for this entire period without dry-docking. This will allow to present the ECOTEC-STC system as part of a maintenance package deal to ship owners and ship managers.
Favouring future take-up, the beneficiary succeeded in obtaining permission for underwater cleaning of ships treated with Ecospeed in several ports where this had previously been prohibited, including Rotterdam, Copenhagen, and Hamburg. Uptake in the shipping industry was also promising, with over 100 Ecospeed applications by the project’s end.
Furthermore, the industrialization of the ECOTEC-STC concept and especially the maintenance part of it, will create new business opportunities in all major ports in Europe as the project had foreseen as a new business the provision of the maintenance for vessels and ships. At the end of the project, the beneficiary had already set up service stations in Spain, India, United States and Gabon and had agreements with external service contractors in many more locations.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see Read more section).