Anti-fouling, is the name given to the measures taken to stop algae, weeds, barnacles, mussels and other organisms (collectively known as bio-fouling) from growing where they are unwanted.
Bio-fouling grows naturally on any unprotected surface that is in contact with fresh water or seawater, from boat hulls and outdrives to ships, oil rigs and fish farms.
Left unchecked, marine bio-fouling can increase hydrodynamic drag by up to 60% with an associated spike in fuel costs and greenhouse gas emissions.
Bio-fouling can also clog raw seawater cooling systems, causing main equipment to overheat and fail.
95% of all other anti-fouling systems rely on toxic biocides to kill organisms, and widespread self-polishing coatings that leave poisonous trails of microplastic pollution in their wake.
In contrast, Sonihull ECO is an effective, Zero-Harm, Environmentally-Safe solution to unwanted bio-fouling.
Rugged ultrasound transducers are bonded to the dry side of the surface or equipment being protected.
Ultrasonic pulses from the transducer produce a pattern of increasing and decreasing pressure on the surface being protected. Through the process of ultrasound-induced non-inertial cavitation, microscopic bubbles are created as the pressure drops and are popped as the pressure increases.
The process does not cause any surface damage and the ultrasound frequencies used don’t propagate far from the vessel surface and are inaudible to marine mammals and fish.
As well as actively preventing the creation of a biofilm, the micro-jets created during bubble-collapse have been proven to prevent barnacle and mussel larvae from embedding on the surface.
By slashing your haul-out, cleaning and re-coating costs, Sonihull ECO could pay for itself in as little as one boating season.
You will still need an external coating, but hard, slippery coatings without any biocides can be kept clean with Sonihull ECO.
The Green Marina project in Norway, which is supported by the World Wildlife Fund and the Norwegian government, has proven that for leisure boats, only three items are needed to keep a hull free from marine bio-fouling. A hard hull coating, a Sonihull ECO ultrasonic antifouling system and regular high-speed use (or a run through an in-water boat wash).
The hard coating provides waterproofing and a slippery surface to maintain as-new vessel performance. It also allows for good transmission of ultrasound and makes it difficult for organisms to establish a foot-hold.
The Sonihull system prevents macro fouling like barnacles and mussels from attaching and disrupts the first stages of the food chain.
The boat wash or regular use at fast speed, will remove any persistent slime and take care of any waterline weed.
Sonihull ECO uses non-inertial cavitation induced by ultrasound to keep bio-fouling at bay.
The process is an established technology, usually associated with cleaning solid surfaces in fields as varied as jewellery and industrial cleaning.
Sonihull ECO ultrasonic anti-fouling systems disrupt the formation and proliferation of marine colonies and provide an effective means of preventing mussels and barnacle larvae from attaching to hard surfaces in raw seawater.
The process of ‘non-inertial cavitation’ should not be confused with ‘inertial cavitation’. The latter is the process that can damage propellers or the insides of pumps. But the forces involved with non-inertial cavitation are much lower.
So, with Sonihull ECO, there is no chance of surface damage, like erosion or pitting. That kind of physical damage can only be caused by inertial cavitation.
The only material that Sonihull does not protect from bio-fouling is wood.
The system relies on internal resonance to transmit the ultrasonic signals to the surface being protected.
Compared to man-made materials, wood is full of varying densities and voids and is not an efficient transmitter of ultrasound.
Sonihull ECO provides effective anti-fouling protection for solid materials, including Steel, Stainless Steel, Aluminium, GRP, FRP, Kevlar, Titanium and rigid plastics.
Note – The protection of certain concrete and ferro-cement structures will depend on their individual composition.
Silicone-based coatings are known to dampen up to 40% of ultrasonic signals and will reduce system effectiveness.
Each Sonihull ECO transducer only consumes about 3.6 Watts.
This makes the system ideal for on-board, standby or remote powering options, using 110-240 Volts 50/60Hz AC or 22-30 Volts DC supplies.
Ultrasound is beyond the audible spectrum of marine mammals and fish. The low-powered ultra-high frequencies used by Sonihull are completely harmless to marine mammals and fish. Also, the ultrasound frequencies emitted by Sonihull’s transducers do not propagate far from the surface being protected.
Ultrasound should not be confused with low-frequency sound waves which are within the audible spectrum and can propagate for many miles underwater. Low frequency and sub sonic pressure waves are caused by things like underwater explosions and can be disruptive to large sea-dwelling mammals like whales and dolphins.
Unlike anti-fouling coatings, Sonihull ECO does not rely on poisonous biocides or the release of microplastics from ablative coatings to be effective.