Ultrasonic anti-fouling for Norbulk tankers

The Sonihull8 system, which uses ultrasonic pulses to prevent marine organisms colonising solid surfaces, has been installed on 44,000dwt double-bottomed tankers Hassi Messaoud 2, Alrar and Rhourd Enouss. Bio-fouling in the raw seawater circulation pipes could otherwise lead to blockages and possible damage due to overheating.

Sergejs Bondarevs, technical superintendent, Norbulk Shipping UK, said: “We have already increased the back-flushing intervals on our central coolers and we are looking forward to rolling out similar savings across the fleet.”

Sonihull8 differs from impressed-current systems in that it does not rely on electrolytic release of metallic ions to deter organisms and so does not require sacrificial anodes. The system’s eight transducers can be controlled from a single panel, minimising installation work, with no drilling or current isolation required.

“Owners and operators can expect a reduction in capex and lifetime maintenance costs of up to 95% when compared to impressed current systems,” said Darren Rowlands, commercial director, NRG Marine.

The system also contributes to requirements for a vessel’s Green Passport Inventory for hazardous materials