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Offshore Support Journal

Offshore Support Journal

Fast-evolving access systems have lifting capability and provide continuous connection

Tue 07 Nov 2017

Fast-evolving access systems have lifting capability and provide continuous connection
Uptime’s 23.4 m active motion compensated gangway on Island Crown connects to the Oseberg H unmanned platform

Offshore access systems continue to evolve as does the market for them and the geographical extent of that market, as recent product announcements and contracts make clear

 

First-generation offshore access systems were designed purely to safely transfer personnel, but as they have evolved, so they have become capable of transferring personnel and equipment and, more recently, acting as cranes, lifting loads onto offshore platforms. They have also evolved to be able to provide continuous transfer capability rather than regularly needing to disconnect, interrupting transfer operations, and to be able to operate in more and more challenging conditions.  

An example of this ability to act as a crane is Ampelmann’s E1000 gangway, which has been modified to speed up conversion from personnel to cargo mode from around 10 minutes to less than one minute.

As with a number of personnel transfer systems, the E1000 can transform from a gangway into a crane boom. It is 30 m in length and is capable of transferring people and up to 1,000 kg of cargo in wave heights up to 4.5 m.

Van Aalst Group in Dordrecht says its 28 m long Seagull access system is able to compensate for vessel movement in a significant wave height of up to 3.5 m when installed on a typical 75 m long supply vessel. The company claims that this results in an operating window that is “significantly higher” than other available systems in the market.

The first SafeWay gangway is currently installed on the 95 m offshore construction vessel Olympic Intervention IV. The dynamic positioning class 2 vessel has been providing accommodation and work space for up to 100 offshore workers, having been chartered by Adwen for maintenance activity on three windfarms in the German sector of the North Sea.

“Under sometimes challenging weather conditions, with significant wave heights exceeding 2.8 m, 851 transfers have been carried out after a total of 173 landings on a turbine,” said the company. The unit also carried out an additional 301 cargo transfers. The gangway incorporates a compensated lifting capability with a separate winch to transfer loads of up to 400 kg.

Adwen site manager Ralf Schuckert said the company had experience with other offshore access systems but believes that the Seagull has some advantages compared to others, not least its ability to lift loads 10 m vertically and its ability to ‘hover’ above the target to which personnel and equipment are being transferred.

“Not only does the vessel get more freedom in heading, it also gives the access system greater workability compared to other systems,” he said. Stepless 10m height adjustment, enabling the access system to maintain a nearly horizontal position in all conditions, means offshore workers don’t have to walk up or down an inclined system. The master of Olympic Intervention IV, Endre Stakvik, said “I have never worked with a walk-to-work system that can be lifted vertically. It was amazing to witness the speed of personnel and cargo transfers.”

Another well-known manufacturer, Uptime in Norway, says its Uptime 23.4 m active motion compensated gangway has achieved TRL 7, Statoil’s highest technology readiness level. During the approval process, the gangway was mounted on Island Offshore’s vessel Island Crown during a walk-to-work charter for Statoil.

SMST in the Netherlands has been awarded a contract for the delivery of an access and cargo tower for Esvagt’s new service operation vessel (SOV). The vessel is being built by Astilleros Zamakona in Spain and will work on the Deutsche Bucht offshore windfarm under contract to MHI Vestas.

The access and cargo tower combines a gangway and elevator for personnel and cargo. The equipment will enable safe, stepless transfer of personnel and cargo from the vessel to wind turbines in a significant wave height of up to 3 m.

A landing height-adjustable trolley at the heart of the system will enable personnel and cargo to access wind turbines from different deck levels on the vessel up to a height of 23 m.

SMST has also been contracted to supply remote-controlled cargo transporters that can transport 400 kg of cargo from below deck to offshore structures. A 3-tonne active heave compensated offshore knuckleboom will be installed atop the tower that will be capable of handling wind turbine components.

Long known as a supplier of access systems for the offshore sector in Europe, UK-based Osbit recently broke into the Chinese market for the first time and believes it has solutions that will help reduce energy costs in many other countries.

October 2017 saw Osbit secure contracts that demonstrated its ability to produce cost-effective offshore access solutions whilst also developing bespoke equipment that provides solutions to project-specific challenges.

The northeast of England offshore engineering and technology company has completed its first project in the Chinese offshore wind market, successfully delivering a bespoke MaXccess crew transfer system, but also announced details of quite a different project to deliver an innovative boat landing and access system that will be fitted to a jack-up accommodation vessel destined for Dong Energy’s Hornsea Project One offshore windfarm.

Brendon Hayward, the company’s managing director, highlighted what he described as China’s “very ambitious” offshore wind targets, along with potential opportunities in Asia in markets such as Taiwan and Japan. However, these countries are not the full extent of the company’s export ambitions – Mr Hayward also highlighted opportunities elsewhere, such as in the Middle East in related markets such as offshore oil and gas.

In the Middle East, environmental conditions are more benign than in the North Sea and some other regions, and Osbit’s ability to provide cost-effective solutions could come into play. In regions such as this, Mr Hayward believes, there is growing recognition that ‘bump and jump’ is no longer a satisfactory – or sufficiently safe – way of transferring personnel from boat to boat or boat to platform. Equally, said Mr Hayward, in other parts of the world, demand is growing for access solutions for vessels that can compete with helicopters for long-range personnel transfer. 

“Unlike some companies in the offshore access system market, we are not seeking to be a rental company,” Mr Hayward told OSJ. “Our focus is on supplying the best possible equipment and on problem solving for clients with specific requirements.”

The Chinese deal saw Osbit deliver an improved T12 walk-to-work system that will be installed on a 20 m crew transfer vessel under construction by the Aurora Yachts shipyard in Dalian, China. It is part of Osbit’s growing range of active and passive modular access systems, which support catamaran crew transfer vessels, SOVs and jack-up accommodation vessels. The project built on Osbit’s previous activity in Southeast Asia, which includes a T18 MaXccess system that has been operating successfully at the Fukushima offshore windfarm in Japan for the past three years.

The innovative boat landing and access system for the Hornsea Project One offshore windfarm demonstrates another aspect of the company’s capability. It was commissioned by Aberdeen-based Gulf Marine Services (GMS) UK Ltd and will be installed on one of its self-elevating, self-propelled, dynamic positioning ‘large-class’ accommodation vessels.

GMS required the development of a system to facilitate crew transfers to and from a jacked-up vessel to crew transfer vessels and offshore substations. Utilising a unique access tower with an integrated boat landing, technicians will be able to safely access transfer vessels regardless of whether the accommodation vessel is in a floating position or has been jacked up to a pre-determined deck height of 21 m above sea level. Osbit’s system, in accordance with GMS’s requirements, is integral to allowing work crews to remain offshore, rather than making daily trips to and from shore, and will facilitate up to 50 crew transfers each day.