With offshore projects taking place ever further from shore, Damen's FCS 7011 seeks to challenge the dominance of helicopters as a safer, more efficient crew transfer system
Damen’s 7011 fast crew supplier has been designed to achieve high speeds in a bid to minimise travel time. This is particularly important as many offshore projects are now taking place some considerable distance from shore.
The 7011 design has now been finalised, with tank testing completed and construction of the first vessel anticipated to start in the Q3 of this year in Turkey, with completion expected by the end of Q2 2020, according to Damen’s business development manager David Stibbe.
Design work started in late 2015; at the time, Damen already had ideas surrounding a high-speed crew transfer vessel, and it began seeking input from customers to ensure the new vessel met their needs. Offshore oil and gas companies such as Shell, BP and ExxonMobil had particular requirements in areas such as speed, sea state, transfer window time and comfort levels on board the vessel, explained Mr Stibbe.
Assistance was also provided by research institutions such as TU Delft, a maritime engineering and hydrodynamics-focused Netherlands-based technical university. It worked with Damen on the Sea Axe hull design, which is incorporated into many of Damen’s larger vessels.
Tank-testing was carried out at TU Delft with a 2.8 m 1:25 scale model of the vessel undergoing testing at 30 and 40 knots to simulate 2-3 m significant wave heights. It was found that the vessel’s movements became calmer as the speed increased.
“This is because the forward energy of the vessel allows it to go through the waves, instead of going over them,” said Damen product portfolio manager for research Albert Rijkens. “At the same time, the Sea Axe bow shape reduces any uncomfortable slamming that might occur during high-speed transits,” he added.
Another aspect of testing involved the vessel's resistance at speed. “Our results showed that, due to its long and narrow hull, the FCS 7011 has relatively low resistance,” said Mr Rijkens.
Positioned at the stern of the model, the FCS 7011's ride control system – which measures ship movement and continuously determines the position of active control mechanisms through these signals – was also put through its paces. “The effectiveness of the system – enabling us to improve comfort levels even further – was also validated in these tests,” added Mr Rijkens.
"The forward energy of the vessel allows it to go through the waves, instead of going over them"
The Netherlands Organisation for Applied Scientific Research (TNO) advised on how to minimise motion sickness and boost passenger comfort through a host of methods, including the positioning of seating and windows, window size, ceiling height, HVAC systems, vessel layout, and even what drinks should and should not be served to passengers.
From the start of the project, Damen worked with suppliers to design the 7011, notably collaborating with Ampelmann on the walk-to-work gangway and Veem on the vessel’s stabilising gyroscope. The gangway comes with Seaqualize balancing technology, resulting in enhanced energy efficiency. Measuring 28 m long, it enables a continuous flow of personnel and is capable of transferring 50 people in five minutes. Veem’s VG 1000 SD stabiliser, meanwhile, gives the gangway a roll reduction of up to 70% in 2.5 m significant wave heights.
While the gangway is optional, Damen says the vessel represents the next generation of crew change and hence it does not see basket-based transfers as being part of the equation. The stabiliser is likewise optional, but Mr Stibbe pointed out that while omitting this would save money and weight, it would negatively affect roll-reduction capabilities while at a standstill. While Damen is in discussions with other suppliers, such as Netherlands-based SMST, the first vessel at least will be equipped with an Ampelmann system, said Mr Stibbe.
Other areas that can be customised include the engine configuration, with several layouts available. The default configuration involves four MTU 4000 engines giving 12.5 - 14.4 mW and producing speeds of up to 40 knots; Damen is also offering Caterpillar and Cummins systems as alternatives.
While some aspects of the design, such as hull length, are standardised, the vessel’s interior allows for a high degree of customisation. High-density seating can accommodate up to 150 persons; though if a customer opts for a luxury solution incorporating lie-flat seats, capacity falls to less than 100. There is also provision meeting rooms, while accommodation spaces are placed amidships to maximise comfort and reduce seasickness.
Unlike other vessels in the crew-supply role, which are often catamarans, the new Damen design is a monohull. It uses the company’s trademarked ‘super-slender’ Sea Axe hull shape, a hullform specifically designed to provide high-speed vessels with improved seakeeping characteristics. In the Sea Axe, Damen sought a design that could maintain high speeds in strong winds and heavy seas and provide those on board with a high level of comfort. Derived from the company’s high-speed ‘Enlarged Ship Concept’, upon which a number of Stan Patrol vessels are based, the Sea Axe took Damen’s design significantly reduces resistance, fuel consumption and emissions.
Dynamic positioning capability is provided by Kongsberg, and the DP2 design provides a broad range of marine access solutions for sea states of up to 3.0 Hs. The vessel will be able to land personnel on platforms and floating production units up to a landing height of 20 m, while providing a fast and comfortable crew change solution.
The vessel has attracted most interest from Brazil, West Africa and the Gulf of Mexico, according to Mr Stibbe, but operators in new frontier areas such as Guyana are also expressing interest.
For the US and Gulf of Mexico market, Metal Shark, based in Franklin, Louisiana, will be responsible for producing FCS 7011 vessels. The US shipyard is purpose built and offers indoor weather-independent construction and direct deepwater access to the Gulf of Mexico.
Data analysis improves efficiency
Customers will have access to tools developed by Damen to assist in evaluating the performance of the 7011. One such tool provides a detailed operational expenditure (opex) analysis, incorporating daily costs and maintenance costs, to allow for a granular overview of the vessel’s capabilities. The second tool is a hardware-in-the-loop simulator system, which creates a ‘digital twin’ of the vessel to accurately model its characteristics and its constituent systems and equipment. “This will allow Damen to demonstrate the vessel’s workability based on its characteristics, along with the gangway and DP controller,” said Mr Stibbe, adding “This is an important tool because most questions from oil companies are about workability.” The system provides data on the vessel’s operational limitations, such as how it handles various sea states and how many days per year of operational capability can be expected.
Fast crew-transfer vessels such as the FCS 7011 are expected to challenge the dominant position of helicopters in the offshore crew transfer market, being safer, more comfortable and more cost effective. While operators may still retain helicopters for VIP transport and search-and-rescue purposes, Mr Stibbe sees vessels such as the FCS 7011 becoming the main offshore workhorses. Their adoption may well be facilitated by systems such as the opex analysis tool and the hardware-in-the-loop simulator, which give oil companies the information they need to determine whether helicopters, or water-borne alternatives, will win out over the coming months and years.