Sonihull Ultrasonic Anti-Fouling system used by Dutch MoD

Lamers System Care recently installed the Sonihull Ultrasonic Anti-Fouling system on 11 landing-craft vessels for the Dutch Ministry of Defence, to keep them free from algae, weeds and other biofouling.

The Royal Dutch Navy, along with its worldwide fleet and personnel, is committed to maritime safety and the protection of the marine environment. With sustainability in mind, the Ministry of Defence chose Sonihull’s ultrasonic system to provide an environmentally safe solution for the anti-fouling of its landing craft.

A Landing Craft Vehicle Personnel (LCVP) is a small vessel designed for the transportation of vehicles or personnel. The type MkV (c) can transport up to 35 fully equipped personnel. The LCVPs are stationed in a protected nature reserve. As a result, anti-fouling coatings that contain toxic chemicals cannot be applied to the ship’s hull in case harmful substances end up in the nature reserve’s water.

Because traditional biocide-based anti-fouling can’t be used, the ships’ hulls are colonised by algae, weeds, barnacles and other biofouling very rapidly. This growth on the LCVPs results in increased fuel-consumption, reduced speed, damage to the hull, and reduced lifespan of the vessel, which is not desirable.

The Sonihull ultrasonic anti-fouling system creates microscopic ultrasound-induced cavitation on the surface of the vessels. This disrupts the first stages of the food chain, without damaging the surface being protected. The action prevents the build-up of algae, slime and bigger, more complex organisms on surfaces where biofouling is not wanted. The system is silent and the movement of water on the protected surface also prevents the adhesion of juvenile barnacles and mussels.

Each of the LCVP units has one Sonihull DUO system, which consists of a control box and two transducers. The transducers are installed on the inside of the vessels to protect the hull from fouling. Instead of the standard composite transducer rings that are glued in place, aluminium mounting rings are used. The rings are bonded to the aluminium hull using a 2-part epoxy resin. The Dutch Ministry of Defence opted for aluminium rings so that it is possible to weld them to the hull if they ever need to be re-located.

The control boxes are connected to both the 220 VAC (shore power) and the 24 VDC, so that the systems remain active 24/7. Due to the extremely low energy consumption (7.2 Watt per transducer), this has no significant impact on the vessels’ energy management.