VESSEL REVIEW | Zenith – Scottish North Sea fisher takes delivery of prawn twin-rigger

Scottish fisher Mark Robertson recently took delivery of a new twin-rig trawler built by Macduff Shipyards to design by Macduff Ship Design.

The 22.75- by 7.6-metre Zenith replaces two earlier Macduff-built vessels in the owner's fleet. Like its predecessors, it will operate out of Fraserburgh in the North East of Scotland, primarily targeting prawns in the North Sea.

The vessel utilises a new hull form concept featuring increased length, a gradual bustle forward of the propeller, and a unique stem where the bulbous bow is not fully submerged but instead tapered gradually into the bow's upper region. With the aid of CFD technology, Macduff determined there was a significant reduction in hull resistance at test speeds of eight and 10 knots.

The design also boasts an increase in beam, which allows the vessel to carry less internal ballast whilst also creating more deck space. The increase in hull efficiency enables the owner to save fuel, and in turn, reduce the emissions and environmental impact of the vessel.

Propulsive power is provided by a Caterpillar C18 447kW IMO Tier III-compliant main engine driving a 2,300mm controllable-pitch propeller. With the same engine driving both propulsion and hydraulics, the engine is kept with an efficient operating window with no significant periods of idling and energy loss.

A selective catalytic reduction (SCR) system and a urea filter are fitted in the engine room. The arrangement was proven to work well during sea trials where the 35dB reduction SCR silencer helped reduce the noise levels throughout the vessel.

The hull is built entirely from steel whereas the wheelhouse and the mast are made of aluminium. The hull features a double chine form, transom stern, and modern bow designed to cut cleanly through the sea with less energy, leading to a reduction in fuel consumption and emissions along with increased crew comfort. Below deck are the cabins, the engine room, the fish hold, and a large freshwater tank forward of the collision bulkhead, whereas above deck are the aft shelter, the galley/mess and side passage area, and the fish processing area winch room.

The owners paid particular attention to the arrangement of the accommodation and fish processing areas. The galley is of considerable size and there are comfortable living spaces for the crew. The fish processing area has been optimised to maximise the use of available space. Care and attention were also placed on the positioning of the equipment to maximise efficiency, thus reducing the crew's workload.

A conveyor belt is fitted to sort the catch in place of a traditional tray. The conveyor lifts the product out of the hopper and six different prawn washers. A flush hold unloading hatch is also fitted in the fish processing area forward to create a larger floor space.

A bespoke hydraulic deck machinery package was fabricated by Macduff Shipyards. This includes a triple barrel winch featuring a Hagglunds CA210 compact motor, two split net drums complete with two Hagglunds compact CA100 motors per drum, two general purpose gantry winches, and a cod end lifting winch. Thistle Marine supplied both the MFB8 landing crane and MBK7 power block crane. A small hoisting winch is also fitted to help move the catch in the hold when landing.

Primary hydraulic power is provided by two pumps driven from the gearbox PTOs. At the owner's request a unique secondary hydraulic system was fitted and features two electric motor-driven pump sets. These two pump sets allow the hydraulics to run very close to full power and speed, providing a net retrieve system as well as full redundancy.

Cooling systems for all engines and hydraulics onboard are served by box coolers supplied by Blokland Non-Ferro. Electrical power onboard is provided by two Mitsubishi 98ekW generators, which are also of sufficient size to run the vessel's power independently, thus providing complete redundancy.

The fish processing deck features a catch handling system built by the yard and Northeast Fabricators. A separate compartment is formed within the fish processing area to house both the ice plant room as well as an access hatch and fixed permanent stair to the hold. The fish hold refrigeration system along with ice machine was supplied and fitted by Premier Refrigeration.

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