Norwegian owner Klaveness Combination Carriers has committed to retrofitting four more vessels with air lubrication systems.
The Oslo-listed company has signed another deal with Silverstream Technologies to reduce emissions further.
KCC said work on the Cleanbu oil product and dry bulk carrier 84,000-dwt Barracuda and the 82,000-dwt Barramundi (both built 2019) will take place first.
This will be followed by retrofits on the 80,500-dwt Cabu vessels Balboa and Baffin (both built 2016).
These ships carry caustic soda and dry bulk cargoes.
The 80,500-dwt Ballard (built 2017) has already been outfitted, while the 95,000-dwt Baru (built 2019) is next in line.
Silverstream founder and chief executive Noah Silberschmidt called KCC a great collaborator.
“The wet and dry bulk sector is an important one for Silverstream,” he added.
The companies say the ships should see a reduction in fuel use of between 5% and 7% by using the system.
KCC also has options to fit the kit on combination carriers built between 2016 and 2021.
The kit uses air-release units along the flat bottom of the hull to create a uniform layer of microbubbles to reduce friction and save fuel and emissions.
Other energy-saving devices
Other efficiency retrofits for the Ballard included a WE Tech shaft generator to convert rotational energy to electricity, a Becker Mewis Duct to improve propeller performance and the use of silicon paint.
All these measures should result in an energy efficiency improvement of 15%, KCC said.
Separately, Silverstream said it has signed an agency agreement with technical services provider Franman to support sales of the system in Greece.
As of November 2023, there are 180 vessels contracted to have the equipment installed.
Clients include MSC Mediterranean Shipping Company, Maersk, Grimaldi, Shell, Vale, Carnival and Adnoc Logistics & Services.