HARSH WEATHER CREW CHANGE IN THE 21ST CENTURY
In the world of offshore crew transport, much of the recent focus has been on developing high speed, efficient vessels for use in the relatively benign waters of the southern North Sea, Gulf of Mexico and similar environments, and on the start of the construction of the first of the new high capacity, all-weather Damen FCS 7011 class that is now underway. But for platforms in harsher environments, while their needs remain much the same, the capabilities of the next generation of vessels that will provide them with year-round support need to be of a completely different order. Speed of crew delivery will be limited by the sea states in which they operate, while factors such as safety, comfort and the ability of personnel to begin work immediately on arrival even in bad weather will be of much greater importance. Added to that will be the need to cater for the higher landing heights.
The new solutions will also need to be economically attractive. The potential cost savings to be made by replacing multiple one-stop helicopter journeys with single, vessel-based, roundtrips serving a series of platforms will need to be demonstrated to be fully achievable. Business Development Manager Ruben de Nie is part of a Damen team that is working on the new class of crew supply vessels that will meet the needs of a key group of offshore operators.
“To satisfy their requirements we are looking at bigger vessels than those typically found in the fast crew supply segment,” he explains. “With our mid to long term focus on the requirements of operators in the central and northern North Sea and other hostile environments such as polar regions, larger vessels are required for better seakeeping in winter weather. With our clients’ objectives including de-risking the crew transfers by reducing helicopter usage while increasing comfort and minimising logistical costs, our designs are initially tailored to address the weather and sea states, both heights and periods, that can be encountered in the central and northern North Sea.”
In order to meet its clients’ needs Damen intends to develop the crew change solution in partnership with key suppliers to ensure that the vessels work effectively as a whole, and that means that vital components are developed in parallel with the vessels themselves to guarantee that they work as single, seamless units. Damen is already working with leading gangway supplier Ampelmann to create an integrated crew change solution in the form of the FCS 7011, and a similar partnering approach will be needed for the harsh weather crew transfer vessels. Not only will the anticipated operating conditions and required crew transfer rates for the gangways require detailed analysis so as to maximise capacity and capability, the greater landing heights found on platforms where the wave heights can be substantial during bad weather will need to factored in while at the same time as the weight of the gangways will need to be minimised in order to preserve stability.
The importance of the vessel and gangway operating as a single, integrated solution so as to maximise Walk 2 Work capability cannot be exaggerated. Damen is also in discussions with energy logistics specialist Peterson exploring the contribution that its expertise can make to the creation of a vessel type that will set new standards of operational efficiency.
Innovation built on experience
“We are working on a completely new design,” continues Ruben, “and exploring the feasibility of using a number of different hull shapes as no current crew transfer vessel can offer the combination of speed, accommodation standards and gangway capability that will be required, but that doesn’t mean to say that we are not looking at elements of our existing portfolio to see what we have that can be adapted to this new role. We have, of course, our FCS 7011 and ASV 9010 vessels as an excellent starting point, but we are also reviewing our 120-metre FIRM concept; a Fast Inspection, Repair & Maintenance vessel as a possible basis for a monohull solution. It has many of the necessary attributes; excellent seakeeping, a maximum speed of 22 knots and high DP performance, that we seek. The vessel dimensions would need to be optimised for the role and the accommodation would of course need to be redesigned and upgraded, but it gives us a solid basis from which to start. We are also looking at our offshore patrol vessels, which are designed to deliver high hull speeds in all weathers without compromising their stability and operational effectiveness.”
High quality accommodation offering a comfortable and restful experience is of course a vital element given that these vessels will potentially be servicing clusters of installations far offshore in a single trip. The designs are being based on the maximum transit time for any individual installation operative being no longer than twelve hours. “Twelve hours is the maximum transit time allowed without permanent overnight accommodation,” explains Ruben. “Removing the need to provide sleeping cabins will substantially decrease build and operating costs, and in fact the majority of the platforms being served will be well within the 12-hour range. Even so, our current approach is to develop a high-quality interior that would feature business class seating for approximately 120 personnel within a comfortable and well-thought-out lounge environment with plenty of natural light. As part of our strategy of identifying applicable designs and concepts from our existing vessel portfolio we are considering lounge formats that would take ideas from high-class ferries and also incorporate the functional luxury of Damen’s latest generation of crew supply vessels such as the FCS 7011.”
Design principles of the Harsh Weather Crew Change Vessel
Getting it right from the outset
A vital part of the development process for any new class of vessels is detailed consultations with prospective owners and operators. The Damen development team is paying particular attention to those operating out of the northern Scottish port of Aberdeen and Stavanger in Norway. As the hubs for O&G operators in the central and northern North Sea, the platforms they serve operate in the harshest environments making them ideal locations for ‘slow’ crew transfer. A crew transfer vessel with a cruising speed of around 18 knots would therefore have a range of more than 200 nautical miles within the 12-hour time limit, putting the majority of central and northern North Sea platforms well within range and enabling the servicing of multiple platforms in a single round trip..
As well as a continuing dialogue regarding operational matters such as the anticipated number of vessels required and the frequencies at which they would operate, conversations are taking place regarding what would be the most effective business models. In particular, the potential for sharing agreements to maximise efficiency and so reduce costs even further. These sharing agreements could cover both multiple owners sharing a single or pool of vessels, or individual vessels carrying a number of teams of personnel from different operators on a single voyage. Whatever the operational arrangements, maximising utilisation is key to economic efficiency.
A new paradigm
One thing is for certain, the demands of today’s end users will ensure that the harsh weather crew transfer vessels of the next decade will be very different to current platform supply vessels, despite being of a similar size. “They will be something not seen before,” confirms Ruben de Nie. “Not only will they look different both inside and out, the way in which they operate will also be something new. Some elements will be broadly familiar. For example, we expect that the Sea-axe design will have a role to play along with DPS using retractable bow thrusters. The passenger area will be amidships for maximum comfort and a large horizon, and a storage area bulk liquids, containers and other cargo will be part of the overall format. But each will be redesigned from first principles to ensure that they are fully optimised for their purpose.”
Currently, the consultation process is in full swing with Damen design proposal engineers incorporating the input of the various partners into the early concepts. This will continue through the remainder of 2019. 2020 will see the team expand rapidly as the design phase gets underway and launch customers become involved in the details of capability and fitting out. “With a fair wind behind us we could see the first of this new class becoming operational in 2023,” says Ruben. “That would be very exciting indeed.”