Macduff Shipyards have delivered their latest newbuild, a twin-rig trawler for Peterhead fishing company MV Gracious Ltd. This is a new design, developed for fishing mainly prawns on North Sea grounds.
When the owners came to the yard, the decision was taken at an early stage to develop a new hull form for the new Gracious, aiming for high propulsion efficiency, good seakeeping properties and comfortable crew conditions. The resulting 25-metre design with a 7.50-metre beam provides a vessel with a registered length just under 24 metres, and the hull lines were tested at the Wolfson Unit to compare against previous designs, using Computational Fluid Dynamic technology to assess hull resistance at a range of different speeds, as well as visualise where major resistance was occurring.
This information made it possible to refine the design, further reducing resistance, and improving the wake that the propeller operates in. The initial results from sea trials were encouraging, with a good speed to power, and the vessel capable of punching effectively into head seas, with little effect on speed.
The general arrangement was carefully considered with crew comfort in mind, with a focus on reducing noise levels in the living spaces within. The generous length made it possible to place cabins amidships, between the aft engine room and the fishroom, which keeps them clear of the propeller which is one of the primary noise sources.
The galley and mess area are located athwartships, above the cabins, with no part adjacent to the engine room. Another effort to reduce noise was to route the engine exhausts up the trawl gallows, instead of near the wheelhouse where they would traditionally be placed. During sea trials, the noise levels were measured and a noticeable reduction in dB was witnessed, with an absence of any propeller noise or vibration in living compartments.
Gracious has been built under cover from start to completion at the yard’s fabrication hall at its Macduff yard. The steel hull and the aluminium wheelhouse and mast were all cut by Macduff Profilers using CNC plasma and gas cutting machines, working with a sa steel kit supplied by Macduff Ship Design.
The main engine is a Caterpillar C32 rated 559kW. This is coupled to a Masson Marine W7400 gearbox, with a large reduction ratio of 9.077:1, driving a 2500mm diameter propeller, fitted within a high thrust nozzle. This is a tried and tested propulsion layout and Gracious is the eleventh newbuild fishing vessel delivered by Macduff with this propulsion package. The main engine is the first Tier III certified C32 fitted in the UK, on any vessel, with the SCR and ancillary equipment for UREA dosing and NOx monitoring supplied by Finning Caterpillar. A stainless-steel urea tank is situated in the engine room, with capacity of close to 2000 litres.
Gracious features a new design of rudder blade, developed by the yard, with CFD analysis carried out by the Wolfson Unit. The rudder features two blades of aerofoil profile, driven by a Scan Steering MT 1000 steering gear unit. The system features no linkages and is simple to fabricate and maintain.
Primary hydraulic power on board is provided by a 199kW Hyundai 4AD086 auxiliary engine, which drives two Kawasaki swash plate hydraulic pumps. In addition, two 45kW electric motors are fitted, each driving an independent hydraulic pump, which can be utilised as a net retrieve system, or for using hydraulic equipment in the harbour with only one generator set running. The hydraulic system is a load sensing type system, with electric control valves and remote joysticks fitted at the machinery. This system delivers power only when requested, with the system running idle when not in use, saving fuel and reducing noise throughout the vessel.
The deck machinery package was supplied by the yard, with a triple barrel trawl winch fitted with Hagglunds compact CA210 motor, as well as two split net drums each with two Hagglunds compact CA70 motors. Thistle Marine supplied the MFB8 landing crane, along with a BK13 powerblock crane, both with slew ring base. A dynamic S45 gilson winch is fitted, plus a small Rotzler hoisting winch is fitted to assist discharging catches.
Electrical power onboard is provided by two 98eKw Mitsubishi generator sets, each capable of running the ship’s power in addition to one of the 45kW hydraulic motor pump sets. If two pump sets are required, the second generator can meet this power requirement.
The electrical system onboard was designed and manufactured by R D Downie, who supplied the switchboards, frequency drives for motors, starter panels for the machinery, fire/bilge/gas alarm panels, and battery systems.
The fish processing system was designed by the yard, with the catch handling system built by Northeast Fabricators, all from marine grade stainless steel.
The fish hold refrigeration system was designed and installed by Premier Refrigeration, who also supplied and installed the Geneglace 2.5tonne/day ice maker. This equipment is all housed in a dedicated room situated between the sorting area and the winch room forward. The 700-box capacity fishroom was finished off with gel coated fibreglass panels and insulated to a high level to save energy and retain cold. A dedicated, fixed, fish hold access ladder was integrated into the walls of the fish hold, to improve crew safety.
