VESSEL REVIEW | Polarbris – Hybrid seiner/trawler delivered to Norway’s Atlantic Seafish

Norwegian seafood company Atlantic Seafish, via subsidiary Polarbris, recently took delivery of a new seiner/trawler designed and built by Danish shipbuilder Karstensens Skibsværft.

The vessel, which is also named Polarbris ("Polar Breeze"), will be homeported in Alesund and will be used as a Danish seiner and netter for groundfish in addition to catching snow crab. This was in fulfilment of owner Polarbris' requirement for a vessel that is capable of working with different types of fishing gear.

"Because it needed to be able to work with different gear types depending on the fishing method, the vessel has an onboard factory that has been laid out to be as versatile as possible to cater to fish and crab caught using the different methods," Karstensens told Baird Maritime.

The builder added that the vessel was designed with its carbon footprint as one of the key considerations, hence the inclusion of such features as a highly efficient powerplant, a slow-revving propeller, and a Corus Orca Energy 600kWh battery pack.

"The hull shape has been developed and tested using CFD, and the wave-piercing stem was proven to be satisfactory even in bad weather."

Built with an emphasis on energy efficiency

The newbuild has an LOA of 43.5 metres (143 feet), a moulded beam of 11.5 metres (37.7 feet), a depth of 4.1 metres (13 feet), a gross tonnage of 900, and accommodations for 12 crewmembers.

A Yanmar 6EY22AW 1,370kW (1,840hp) engine drives a large-diameter Brunvoll Volda controllable-pitch propeller via a Brunvoll Volda gearbox to deliver an operational speed of between nine and 11 knots as well as a top speed of 13 knots. Electrical power is drawn primarily from a Cummins PTO shaft generator with a Scania DI16 generator serving as backup.

The propulsion setup also includes a 500kW retractable azimuthing thruster and 190kW side thrusters. The owner selected a retractable thruster for installation as the concept has been proven during operations in bad weather. Specifically, the thruster can be used to provide limited propulsive power in place of the main propeller during certain activities, such as when the crew are pulling nets, or for positioning the vessel.

"The main engine is relatively small but it is coupled to a heavy duty gearbox with large reduction for turning the large-diameter propeller," added Karstensens. "This combination delivers highly efficient thrust during fishing and at normal sailing speeds."

The winches, the net drums, and the other deck equipment supplied by Evotec are electrically-driven to help reduce emissions. The electric deck equipment also contributes to efficiency, as the vessel will operate for much of the time as a seine netter with the winches running almost continuously. Three of the winches can be used for twin-rig trawling of whitefish and shrimp.

Excess power generated by the use of the electric winches can be stored in Polarbris' 600kWh battery as a form of energy recovery. The battery pack can also provide two different means of peak shaving: peak shaving excessive electrical power consumption and peak shaving main engine/propulsion variations when fishing and operating in heavy seas.

"The battery pack can also supply the vessel's electrical power requirements while in port, thus freeing up the auxiliary engine for recharging the batteries at certain intervals," said Karstensens.

A power management system is also fitted to regulate power consumption.

Comprehensive deck equipment and electronics fitout

Polarbris is fitted with cranes from Tadano and Seaquest forward and aft of the superstructure. The factory deck provided by SteelTech has a Carsoe crab handling line, Baader heading machines, and KM Fish Machinery gutting machines. Also fitted is a Marelec sorting and weighing system.

The vessel boasts DSI vertical freezers and a cargo freezing system from Teknotherm. The ammonia refrigeration machinery consists of plate freezers, flake-ice makers, and an RSW cooling system. The cargo holds placed within the 470-cubic-metre (16,600-cubic-foot) fishroom are furnished with overhead air coolers for natural air circulation for storage of frozen and chilled product.

A separate tank with capacity for 4,200 litres (920 gallons) will be for storing live groundfish.

For electronics, the vessel relies on a sonar and sounder from Simrad, Sailor VHF radios, MaxSea and Olex plotters, and a GPS, AIS, and radars from Furuno.

"The main challenge we faced was in making sure all the necessary equipment can fit in a 43.5- by 11.5-metre hull," Karstensens told Baird Maritime. "This was especially true for the factory deck area."

Design work on Polarbris was done in compliance to DNV class requirements. Construction of the hull took place at Karstensens Shipyard Poland while final outfitting was undertaken at Karstensens' Denmark facilities.