VESSEL CONVERSION | AQS Merlin – Delousing boat upgraded for general fish farm support duties

Norwegian shipbuilder Vard has completed upgrading work on a lice treatment vessel to enable her to take on a new role as a service platform.

Owned by Norwegian aquaculture services company AQS, the Lloyd’s Register-classed AQS Merlin underwent the conversion works at Vard Søviknes.

The vessel was originally built in 2008 in Malaysia as Guard Merlin, a platform supply vessel (PSV) intended to support clients in the offshore oil and gas industry. In the succeeding years, she was successively reconfigured to take on other roles such as offshore towing and was eventually modified for delousing duties at fish farms in Norway in 2016.

Validating PSV conversions for duties outside of the offshore industry

The decision to modify an existing vessel to take on a new role follows the practice of a number of other Northern European operators, as repurposing existing tonnage has been regarded as a more cost-effective solution in a number of cases in the region instead of opting for new construction.

Also, as demonstrated through a number of earlier refit and conversion projects, PSV hulls are ideal vessels for possible upgrades and repurposing due to their significant inherent transport capacities.

The conversion at Vard Søviknes entailed removal of nearly 100 tons of delousing equipment and the installation of a new Veth jet thruster to deliver more precise manoeuvrability while generating reduced noise and emissions. This will allow the vessel to navigate more effectively at offshore fish farm sites and to position herself safely when servicing pens.

Modifications allowing for greater transport capacity

The vessel has a steel hull, an LOA of 48 metres (160 feet), a beam of 11 metres (36 feet), a maximum draught of 3.5 metres (11 feet), a deadweight of 541, a gross tonnage of 498, and a bollard pull of 38 tonnes.

Because the vessel is no longer primarily outfitted for delousing, the resulting available onboard space could now be used for carrying supplies, tools, and replacement parts. The vessel also boasts greater mobility, allowing for increased coverage in any given period of working at farms.

The deck equipment consists of a tugger winch, an HS.Marine crane with lifting capacity of 185 tonnes, and two smaller Palfinger Marine cranes with lifting capacities of 65 tonnes.

The propulsion arrangement meanwhile includes two Cummins KTA50M2 engines that each produce 1,700 hp (1,300 kW) to deliver a service speed of 12 knots, enabling easier relocation between pens as well as to and from shore.

AQS Merlin has been used for positioning and towing duties following her conversion. She has been operating primarily in Norwegian coastal waters.