McMullen & Wing masterpiece of marine engineering entrusted to safety and performance of Hydraulink hose and fittings
Masterpieces of marine engineering – left, the Palfinger folding crane for the Pakihi Kura and, right, the America’s Cup winning yachts also using Hydraulink hoses and fittings with their hydraulically actuated foil cant system.
So the safety and comfort of the crew were a priority consideration for McMullen & Wing, who were ideally equipped to answer the challenge with their history of building seagoing super yachts and extremely hardy work boats,” said Hydraulink Area Manager, Craig Jenkins.
McMullen & Wing’s marine expertise was complemented by its partner Hydraulink’s own expertise as the supplier of hydraulic hoses and fittings for the ultra-fast 2021 America’s Cup challenge in which all competitors, including the winning Emirates Team New Zealand, used a hydraulically actuated foil cant system to raise boats clear of the waves as the 6-7 tonne AC75 yachts hit top speeds between 40 and 50 knots depending on conditions in the Hauraki Gulf.
“A top class hydraulic system is critical to the operation and safety of any mussel farming vessel – and McMullen & Wing’s hydraulic fitout for Pakihi Kura is a masterpiece,” says Jenkins. “They mapped out the working spaces beautifully to provide easy and swift access for hydraulic installations and service to ensure optimum safety and reliability for the many hydraulic systems on which the vessel depends. Their forethought will pay dividends in terms of system uptime, reliability and safety over years and years to come."
To minimise structure-borne noise and vibration, all piping and tubing installed by Hydraulink is supported in rubber-lined split clamps with secondary isolation on dual-compression mobile isolators
McMullen & Wing Technical Manager Jeff Porter said the collaborative hydraulic system design by Dana Brevini and McMullen & Wing builds on the successful features of another vessel in Whakatōhea Mussels’ fleet, Kukutai, and results in functionality tailor-made for a challenging environment.
“It is a unique design with features that are particularly suited to work boats in many marine environments, including marine transportation, fishing, energy exploration, and other tasks where seaworthiness, manoeuvrability and lifting, loading, and unloading capability are at a premium.”
The vessel’s main deck features a large crane mounted on a fabricated aluminium plinth along with four davits used for handling the mussel lines, plus a line tensioning winch and the mussel harvesting equipment.
The Palfinger PK33002 (M) E folding crane has a maximum outreach of 16m, enabling it to reach anywhere on the vessel. It has a lift capacity of 2,000kg at 9.5m, enabling the crew to offload two 1 cubic metre bulk bags of mussels at a time on to the dock.
The crane features continuous slewing, without any blind spots, so it can be centrally located, adding flexibility to crane operations. The crane is fitted with Palfinger’s electric control system (ECS) featuring electrically operated emergency cutoff and electro hydraulic overload.
Orderly and accessible Hydraulink hosing installations throughout the vessel, with details maintained on file for easy replacement as needed for safety and in-service reliability
“The crane base is also notably different from those fabricated from light plate with extensive stiffening that may be prone to cracking under repetitive high loads.
McMullen & Wing engineered a monocoque structure from heavy plate with minimal stiffening, to reduce stress concentrations and to distribute load from the top plate through the sides and into the deck insert plate and the foundations beneath.”
The vessel’s davits were engineered using McMullen & Wing’s experience with mussel industry vessels, this being the sixth set they have built since developing the first set for Kukutai in 2018. The single-post davits are fitted with double sliding arms and winches, each combination rated at 1500kg SWL
Dana Brevini supply the braked planetary winch drives and directional control valves for the davits whilst custom marinised hydraulic cylinders are supplied by Victor Hydraulics. Hydraulink hose and fitting kits are used throughout, with all details maintained on file for easy replacement as needed to optimise safety and in-service reliability.
A mussel harvesting equipment package from Ansco Engineering includes a powered walking wheel and two idler wheel assemblies mounted on the davits, a powered infeed conveyor recessed flush with the hull side to help bring the mussels aboard, a rope washer, a declumper/washer unit, a size grader along with a series of conveyors that link the equipment together. A standalone mussel seeding machine is also stored on deck and can be shifted in and out of position at the forward end of the main deck using the Palfinger crane. Hydraulink quick-release hydraulic couplings as well as waterproof electrical connectors are located conveniently nearby.
The auxiliary engine pump drive powers five hydraulic pumps supplying four circuits – the deck gear, the deck crane, the bow thruster and windlass, and the seawater pumps. Load-sensing technology is used on two of the circuits to maximise energy efficiency. The vessel’s hydraulic tank stores 2,250 litres, while the circuit volume is close to 3,000 litres once keel-cooling and pipe circuits are included.
To minimise structure-borne noise and vibration, all piping and tubing is supported in rubber-lined split clamps with secondary isolation on dual-compression mobile isolators. Bulkhead penetrations also avoid direct contact between piping and structure.
“Everything about the Pakihi Kura displays quality, durability and outstanding design for trouble-free service,” says Craig Jenkins. “She is pure class.”
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