Stolt Tankers wraps up in-transit hull cleaning trial

Stolt-Nielsen subsidiary Stolt Tankers has completed an in-transit hull cleaning trial using Shipshave’s ITCH on board the Stolt Acer as the vessel sailed from Port Said, Egypt to Algeciras, Spain.

The In-Transit Cleaning of Hulls (ITCH) allows the crew to clean the hull while a ship is sailing, instead of hiring specialists, and dispose of removed fouling far from shores to avoid invasive species disturbing marine life.

It is a semi-autonomous hull-cleaning robot. A winch on the foredeck of the vessel tethers the robot. The robot is equipped with soft brushes, harvests propulsion energy to clean the vertical sides of the hull underwater and sweeps up and down. It travels with a defined pattern with controlled brush forces.

The system is intended to be proactively applied before fouling becomes a real problem, but it can also remove settled fouling by repetitive operations, according to Shipshave.

Following a consumption assessment calculation performed by DNV, it was found that Shipshave’s technology can deliver fuel savings of around 10% when used regularly.

The crew of the Stolt Acer also reported that the device was easy to use, clean and maintain, Stolt Tankers said.

“The results of the initial trial were very positive. We saw a reduction of fuel consumption during the voyage, and this when combined with some of the other technological developments we are investigating will have a significant impact on our overall fuel consumption,” Energy and Conservation Manager at Stolt Tankers, Jose Gonzalez Celis said.

Biofouling on ships’ hulls is a major concern for shipping companies as it not only increases fuel consumption but can also lead to the transfer of invasive species to non-native waters. In transit hull cleaning gently cleans the hull more regularly than manual cleaning by divers. The reduction in the amount of drag due to biofouling consequently decreases fuel consumption.

Efficient consumption of fuel, and overall energy-efficient vessel operation, are becoming ever more important ahead of the impending environmental regulations, including those related to the Carbon Intensity Indicator (CII), set to enter into force in 2023.

Stolt Tankers said it was exploring several technical solutions to support the transition to a low-carbon maritime industry, adding it plans to expand the Shipshave trial to five more ships.

The company has been also looking into the potential of biofuel as well as shore power for its ships to cut emissions.

As explained, a greener future will require “the right combination of new technical solutions, technology, and future fuels.”

“Traditionally, ship owners tend to have a reactive approach to vessel maintenance, rather than taking preventive measures,” said Lucas Vos, President Stolt Tankers.

“As part of our continuous improvement mindset we have turned that idea on its head and found that taking a more proactive stance before biofouling has a chance to settle on a ship’s hull is a far more sensible approach.”

“Reducing the marine growth on the underwater hull of our ships by applying Shipshave’s innovative solution is just one of the ways in which we are improving our energy efficiency with the aim of reducing our carbon intensity by 50% (relative to 2008 levels) by 2030.”