Copper-free easy release coatings in combination with UltraSound AntiFouling (USAF) may well be the future in environmentally friendly antifouling.
Antifouling paints with biocides or copper cause problems for the environment and port regulations prohibiting these types of antifouling are already in place or imminent. At the same time, fouling, such as barnacles, impact biodiversity.
Easy Release Coatings
Easy release coating are environmentally friendly. The basic principle is that these coatings are very smooth. So while these coatings do not prevent fouling, it is easy to remove it.
Hull Cleaning
Depending on the type of vessel and the place it is sailing, the cleaning interval will differ. Vessels not sailing full days, such as service vessels or tug boats, or in bad fouling conditions, for example a warm climate, will grow fouling rapidly, sometimes in just a few weeks.
Hull cleaning costs both time and money. In addition, ports do not want fouling waste in their port, so special equipment is needed, together with proper waste disposal.
Added Resistance Affects Fuel Consumption
Furthermore, before cleaning, a fouled hull results in extra resistance and thus more fuel consumption and ditto CO2 emissions. Tests by TNO (the Netherlands Organisation for applied scientific research) show that this extra resistance can increase fuel consumption by up to 50%.
UltraSound AntiFouling
The challenge is to have a system that is environmentally friendly (no biocides or copper) and stays clean for as long as possible without cleaning. For this, the UltraSound AntiFouling (USAF) system from Luykx Ultrasound was tested in combination with an easy release coating.
The ultrasound system creates shockwaves directly in the water, as opposed to other ultrasonic systems which use transducers glued to the inside of the hull. The USAF shockwaves create an environment where larvae from barnacles prefer not to settle. The shockwaves prevent the barnacle from getting enough food.
USAF Tests
The first test combining an easy release coating and USAF was done in a port in Florida in the summer of 2016. The port is known for its bad fouling conditions. After three months, there were no barnacles on the panels, only slime and some soft fouling.
In 2017, a test was conducted at NIOZ (Royal Dutch Institute for Sea Research), see picture. The white parts were painted with an easy release coating. The parts covered with algae were painted with a standard antifouling coating. A USAF unit was installed and running in the vicinity.
Both tests show that the combination of an easy release coating with USAF reduces fouling and cleaning to a minimum. Further tests show that the USAF does not impact other species, including mammals and turtles.
Picture: Test at NIOZ: USAF (UltraSound AntiFouling) in combination with an easy release coating. The white parts are easy release coating, other parts a normal ship coating, not antifouling. The panel was placed in the port of Den Hoorn, the Netherlands, for two months during late summer 2017.
