Odfjell tests hull cleaning idea

A CLOSE SHAVE

SUSTAINABILITY • THERE ARE MANY WAYS TO IMPROVE VESSEL EFFICIENCY. ODFJELL IS TRIALLING A SYSTEM TO KEEP THE HULL OF ITS SHIPS FREE FROM SLUDGE WHILE UNDERWAY

THE SEARCH FOR greater efficiency in the operation of seagoing vessels, as required by the International Maritime Organisation (IMO), is leading down many paths, with owners and operators looking at different propulsion systems, enhanced hull forms for new ships and operational changes. Ship operators have long known that hull fouling adds to fuel consumption, so that is another area of interest, especially since many traditional anti-fouling coatings have been outlawed because of their adverse impact on the marine environment.

Biofilm begins to form on the hull just hours after a clean ship is put into the water and creates resistance as the ship moves, degrading the hydrodynamic flow along the full and increasing fuel consumption; this is both costly and bad for the environment.

Leading chemical tanker operator Odfjell is examining a solution: a system that brushes marine growth and fouling from the hull at its early stage of formation. The system, developed by Norway-based ShipShave, uses the hydrodynamics from the ship’s forward movement to drive a semi-autonomous robot along and up and down the side of the hull while the ship is underway. A pilot system has now been installed on the 46,000-dwt tanker Bow Elm during a scheduled drydock.

Explaining the ‘In Transit Cleaning of Hulls’ – or ITCH – system, Jan Opedal, Odfjell’s project manager of technology, says “it’s like a snow brush you use on the car”, except it needs no effort on the part of the user. “It is a lightweight, cost-effective plug-and-play system with an in-built camera to monitor growth. It not only saves fees on manual maintenance inspections and cleaning, but also time and fuel as it is done while the ship is on the move. This means that the vessel can be cleaned much more frequently. Conventional hull cleaning methods are often challenging to arrange and demand stops at anchorage or in drydock, stealing time that could have been better spent moving cargo for our customers.”

PART OF THE PLAN While ITCH covers up to 90 per cent of the hull, Odfjell is also trialling Hasytec’s Dynamic

REMOVING HULL FOULING WHILE UNDERWAY SAVES

TIME AND MONEY FOR SHIP OPERATORS Biofilm Protection system on the area around the propeller and its blades. This consists of small transducers that delivery highfrequency ultrasound into the water, which prevents the biofilm from settling. Like ITCH, Odfjell says, Hasytec’s system minimises maintenance costs and is environmentally friendly as it targets only the biofilm and single-cell organisms, leaving fish and marine mammals unharmed.

Odfjell has set itself the target of reducing carbon dioxide emissions by 40 per cent from a 2008 baseline by 2030 and sees this fouling reduction project as just one part of that effort. “It is critical to us to maintain a clean hull and propeller on our vessels,” says Erik Hjortland, vice-president of technology. “Reduced speed or increased consumption due to fouling will negatively affect our Annual Efficiency Ratio. The concept of combining ShipShave and Hasytec has the potential to mitigate this better than by using divers and hull cleaning robots like we do today.” It could prove an important component in meeting the efficiency target.

“Efficiency, fuel consumption and emissions go hand in hand, so Odfjell is improving and renewing the fleet constantly by investing in new ships, retrofit programs and new technology to optimise operations for fuel efficiency,” Hjortland adds.

Odfjell plans to use the two systems in tandem for six months and to collect data about the vessel’s performance and energy consumption to assess their usefulness in meeting its efficiency targets. www.odfjell.com