MacGregor, developer of one of the latest additions to the growing number of walk-to-work motion-compensated gangways, believes its system Horizon has several inherent advantages, not least reduced energy consumption
Designed to optimise the transfer of windfarm technicians and equipment from ships to turbines, the Horizon gangway has been selected for a number of commissioning service operation vessels (CSOVs) – and is now in service on several them – but the company has been coy about releasing details – until now.
“Selecting the right solutions to transfer personnel and equipment efficiently between a CSOV and a turbine is one of the key decisions an owner takes,” says MacGregor, “given that this activity will often define a vessel’s maximum uptime hours: simply put, its ability to earn money for its owner.
“Developing the most efficient solutions for the wind energy market has involved extensive collaboration with clients,” says the company, “with MacGregor contributing at an early stage of vessel design to ensure the position and performance of its equipment is optimal.”
As MacGregor specialist engineer Sindre Halvorsen explained, “The ability of a gangway and crane to compensate for vessel motions will be weighed up in the voyage plan. Accuracy and reliability are critical for planning within safety limits imposed by weather. Effectively, the ability to work alongside determines a vessel’s operational window.”
Providing what MacGregor describes as “best-in-class active motion compensation” to land and work safely in significant wave heights of up to 4.2 m Hs, the Horizon gangway maximises the available time for technicians and equipment to be transferred between the ship and a platform.
Available for newbuild ships and for retrofits, Horizon’s customisable foundations can be integrated with the vessel design and adapted to serve different landing heights and turbine clearance requirements. The solution is also delivered with an extra-wide transfer bridge – 1.5 m, against a class requirement of 1.2 m – for optimised safety, logistics flow, and/or an integrated tower and 26-person elevator to connect goods and technicians between deck and gangway levels. Platform capacity is given as 2,000 kg and up to 10 people.
Based on its design philosophy, but also on feedback from first movers, Mr Halvorsen said the all-electric option is proving increasingly persuasive for gangway specifiers.
“Comparative studies tell us that energy efficiency can be as low as 25% for hydraulic load handling equipment, while electric solutions achieve above 75%,” he says. “Where the Horizon walkway is concerned, the amount of energy needed for operations is very low compared with many of the alternatives – less than 200 kWh per day.
“Based on efficiency, but also on the increasing focus energy suppliers place on sustainability – and especially on CO2 emissions – our expectation is that all-electric transfer solutions may soon come under consideration for inclusion in charter party agreements.”
Another important feature of the Horizon gangway is that it has a level of redundancy that goes beyond class requirements, with an entire electrical system maintaining control and safety levels to handle any single failure.
Horizon’s efficiency is also enhanced as a result of its ability to interface with other shipboard systems. These include MacGregor’s Colibri 3D motion-compensated crane, which has garnered a reputation for flexibility and agility under load, and for its greater precision while less mass is in motion. As a result, said MacGregor, CSOVs have already been ordered which feature the Horizon gangway system, the Colibri 3D motion-compensated crane and MacGregor’s ‘AROS’ remote-control station.
Developed in close co-operation with customers, AROS is an ‘augmented reality’ operator station positioned on the bridge, from which a single operator can switch seamlessly between crane and gangway operation. In addition to the overall efficiency and safety gains this provides, the combination provides another means of minimising unplanned downtime and thereby maximising a vessel’s operational window.
“Digitalisation is also central to our strategy for lifecycle services and support,” Mr Halvorsen explained. “Because CSOVs only earn when they work, their load and personnel handling equipment must be continuously available. Predictive maintenance is a key tool which can enable remote support and enhance planning for scheduled inspections and maintenance.”
Several recent specifications for COSVs have included OnWatch Scout (OWS), MacGregor’s condition monitoring and predictive maintenance application. The predictive software analyses operational data streamed directly from the vessel to detect patterns which might indicate risk of failure, optimise planned maintenance and minimise unplanned downtime.
As MacGregor vice president offshore solutions Kalle Tuomaala noted, as wind turbines get larger and larger, and are installed further from shore, and as the floating wind market emerges, so further technical innovation will be required in what is a fast-expanding industry.
“Whatever the challenges ahead, solutions which can be considered at the earliest stages of vessel design, have capacity for integration and are equipped for predictive maintenance will offer the most effective answers,” said Mr Tuomaala.
“The ability to deliver and recover technicians from a turbine is one of the defining features of the utility of a service operation vessel. Understandably, owners are going to opt for a gangway that ensures operations can always proceed as planned, while less well-equipped vessels may have to stay at home.”
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