Teamwork makes the dream work

Production inventive design in new 35meter fish farming vessel

MOWI Scotland and Inteverlussa Marine services take sea lice management to the next level by expanding the fleet with a 35 meter / <500 Gross ton 3514 Utility vessel with a bespoke Thermolicer® system. MOWI’s main objective of this build is to maximise on-board fish welfare while minimising operational carbon footprint. To meet these progressive demands, Inverlussa who owns and operates the vessel, brought Scale AQ and Nauplius Workboats together in an unique collaboration that was inked earlier this month. 

The 35m x 14m vessel will be built in Holland by Nauplius Workboats and operated by Inverlussa Marine Services. To maximise performance, the vessel will be equipped with twin triple Stranda Prolog vacuum tank fish delivery systems  and a twin-line bespoke Thermolicer® system designed by Scale AQ.  Filtration is provided by Smir using double Hydrofilters along with secondary belt filtration. 

Both the design and execution phase build on an intensive collaboration of experts, including Thistle Engineering (Dougie Gibson and Tony Moynihan), Nauplius Workboats (Gerrit Knol), Stranda Prolog (Jonny Holsen and Klaus Hoseth), Scale AQ (Tore Lasstad, Martin Ramstad) for the specific layouts of the treatment system and Inverlussa Marine Services (Ben Wilson) providing an operational, highly economical vessel.

We are very proud of this design ‘Merging all demands of all our specialists without compromises to aesthetics.” Gerrit Knol Naval Architect of Nauplius Workboats.

Unique to the approach is that the engineering team actually merged the technical systems with the vessel, rather than just fitting them onto the vessel. The Stranda vacuum pump presents a good example;  fish welfare has been top priority from the moment the design process started. As a result, the vacuum pumps are placed in the utmost optimal position for  generating the highest possible fish welfare. Additional components and the vessel itself have been constructed to match the ‘fish-welfare 1st’ approach.

What’s more, the vessel is equipped with diesel-electric propulsion that doubles as operational power supply for the Thermolicer. A logic choice that aligns with the relatively high power demand and operational envelope of the treatment installation.  

The implemented generator configuration facilitates best economical output at lower fuel consumption compared to traditional propulsion systems. 

The ship systems and Thermolicer design resulted in two independent de-licing systems offering a high redundancy fallback in case one of the lines goes offline. This is achieved by installing three generators, of which one remains in standby function, while the other two independently supply power to the de-licing systems. This redundancy concept is continued in the vacuum pump and Thermolicer engineering, to guarantee operational performance.   


To lower the carbon footprint / fuel consumption, Nauplius Workboats designed a heat recovery system to generate the base load heat that is required for the Thermolicer system.

Oil burners are used for temperature fine-tuning only, these burners will be alternatively fuelled by processed fish oil as an additional opportunity to further reduce the vessels carbon footprint.The fish conveying system facilitates a maximum throughput of 340 tons Salmon per hour depending on the size of the Salmon.

To enhance the manoeuvring capabilities along the fish pens, the vessel will be equipped with two VETH Propulsion electrical L-drives and a high output bow thruster. All are connected to a dynamic positioning system. The on board accommodation consists of 3 double and 3 single cabins with a high-end finish to create an attractive “home & work” atmosphere for the crew.

 The collaboration between Inverlussa Marine Services and Nauplius Workboats resulted in an economical, attractive and bespoke design. The vessel will be built under Lloyds Register classification and sail under the United Kingdom flag.

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