An alternative to helicopter dominance

Offshore projects can be quite some distance from the shore and the further out they venture the more the challenges can increase when transporting personnel. In the case of crew transport, Damen has designed a water-borne solution that is intended to be safer, more comfortable and more cost effective than traditional helicopter transport with the Damen FCS 7011 ( fast crew supplier )

FCS 7011 Design

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 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. The FCS 7011 design is now finalised. Tank testing is completed and construction of the first vessel is anticipated to start in Q3 of 2018 in Turkey, with completion expected by the end of Q2 2020, according to Mr Stibbe.

Assistance was also provided by research institutions such as TU Delft, a maritime engineering and hydrodynamics-focused Netherlands-based technical university.

TU Delft carried out tank-testing 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.

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.

Sea Axe bow concept

“the Sea Axe bow shape reduces any uncomfortable slamming that might occur during high-speed transits.”

Vessels in the crew supply role are often catamarans, however the Damen design is a monohull called Sea Axe. This hull design came about after Damen sought cooperation between Delft University of Technology, MARIN and the US Coast Guard. Damen’s exclusively licensed and patented ‘Sea Axe’ hull shape was designed to provide high speed vessels extrodinary seakeeping characteristics, improved crew safety and comfort and fuel efficiancies. The vessels exhibit superior motion behaviour and significantly lower resistance through the water. This leads to a cut in fuel usage of 20% and, consequently, lower emissions.

“the Sea Axe bow shape reduces any uncomfortable slamming that might occur during high-speed transits. 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.

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 at speed” 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”

Walk-to-work

Damen collaborated with Ampelmann on the walk-to-work gangway and Veem on the vessel’s stabilizing gyroscope. Measuring 28 m long, the gangway enables a continuous flow of personnel and is capable of transferring 50 people in five minutes. The gangway also comes with Seaqualize balancing technology, resulting in enhanced energy efficiency. Veem’s VG 1000 SD stabilizer gives the gangway a roll reduction of up to 70% in 2.5 m significant wave heights.

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.

The gangway is optional, however 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 also 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 the Ampelmann gangway system.

Interior

Aspects of the design such as hull length are standardized, however the vessel’s interior allows for a high degree of customization.

“High-density seating can accommodate up to 150 persons “

A luxury solution incorporates lie-flat seats where capacity reduces to less than 100. There is also provisions for meeting rooms and accommodation spaces are placed amidships to maximize comfort.

Engine options

The engine configuration sees several layouts available. The default configuration involves four MTU 4000 engines giving 12.5 – 14.4 mW, producing speeds of up to 40 knots. Other alternatives are Caterpillar and Cummins systems.

Buyers

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 Damen has selected Metal Shark to build and produce the FCS 7011

Metal Shark is an American shipyard based in Franklin, Louisiana, that has indoor construction and direct deepwater access to the Gulf of Mexico.

Results to speak for themselves

“Most questions from oil companies are about workability.” according to Damen’s business development manager David Stibbe. With the FCS 7011 Damen gives its customers access to multiple analysis tools so a client has transparency in regard to the the performance and costs of the FCS 7011. One of these tools provides detailed operational expenditure that includes daily costs and maintenance costs. A second tool is a hardware in the loop ‘digital twin’ of the yacht providing accurate models of systems and equipment characteristics, vessel limitations and how it handles in various sea conditions. Along with this, the gangway system and DP controller, a client will see the vessels workability and advantages as a fast crew supplier.

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. In time the 7011’s data analysis features will give oil companies the information they need to determine where helicopters, or water borne alternatives, should sit in the mix over the coming years.