The Gerritsen On- & Offshore Services BV Company has handled a routine turbine maintenance procedure being undertaken on an offshore location in the Southern North Sea. This involved four of their personnel, utilizing an air operated hoist unit manufactured by the J D Neuhaus company for the safe and effective lift and maneuver procedures for a turbine lift load of 26,500lbs. The turbine was responsible for supplying power to a gas-compressor utilized for power, steam and other general services.
The JDN hoist was a Profi TI and this unit was also combined with an overhead rail mounted trolley, also air powered, to provide horizontal movements of the load. For maximum safety of operation in offshore conditions, a rack and pinion drive was incorporated into the trolley mechanism, with the whole lifting package also incorporating a spark resistant finish for operation within potentially explosive atmospheres. Control operations for the hoist mechanism were incorporated into a JDN E-type pendant controller providing single speed control of the raise/lower/traverse load movements.
The current range of Profi TI air operated hoists manufactured by JDN comprises 13 models covering individual lift capacities from 550lbs to an impressive 100 metric tons. All these models are suitable for use in explosion-hazardous areas, as typically found in offshore environments, providing unbeatable advantages over conventional electrically driven handling products.
They are all designed for easy, quiet operation with 100% duty ratings and unlimited duty cycling. The models include low-headroom and lightweight characteristics, with all hoists also featuring lube-free operation. They are also insensitive to dust, humidity and operating temperatures ranging from 20°C to +70°C, and combine strong, fast, silent operation with safety, as well as oil-free and low maintenance performance. Their Ex classification according to EC Directive on Hazardous Location 94/9/EEC is as standard: EX II 2 GD IIA T4 / II 3 GD IIB T4 and with increased spark protection EX II 2 GD IIC T4. Hoists featuring hydraulic drive mechanisms are also available.
The company has equipped its trenching vessel, Fugro Saltire (photo), with a compact, custom-made, cable-lay spread that comprises a reel drive system to store the cables, a tensioner to lay them, twin winches and a quadrant deployment system on rails. The equipment is fitted to the rear deck of the vessel alongside the existing trenching equipment.
In operation the cables are initially pulled into the base of the wind turbine generators (WTG) and then laid along the seabed using Fugro Saltire’s dynamic positioning system to line them up accurately with the destination WTG. They are then pulled in using the quadrant system to manage the cable during over-boarding and pull-in. The quadrant’s compact design and deployment allows Fugro to control the cable very precisely while pulling in the second end.
An important additional innovation introduced to the system is new 3D sonar technology to supplement ROV support, and monitor precisely, onsite, cable touch down during the cable-lay and pull-in operations, where the daily hazard of very high currents can limit the use of an ROV.
The initial concept for the new cable-lay capability was developed during trenching operations at the Humber Gateway Offshore Wind Farm, when E.ON asked Fugro to investigate laying some cables from the Fugro Saltire. Fugro’s engineers fitted the cable-lay equipment in only six weeks, ahead of E.ON’s deadlines, and cable-laying was completed by February 2015.
“The mobilization of the cable-lay spread on the Fugro Saltire has widened our successful working relationship with E.ON on the Humber Gateway project. As well as trenching 77 array cables, we installed eight array cables along with second end pull-ins of cables already laid by other contractors,” said Mike Daniel, Trenching Business Line Manager at Fugro Subsea Services. “We can now offer clients simultaneous cable-laying and burial from a single vessel, or alternatively our larger subsea construction vessel Fugro Symphony can be laying cables, while the Fugro Saltire is trenching them, speeding up operations and saving time for our customers.”
FoundOcean has been awarded the contract to grout the 150 monopile foundations for the 600MW Gemini Offshore Wind Farm, on behalf of main contractor Van Oord. The project will be the first to use MasterFlow 9800, a revolutionary new material jointly developed by FoundOcean and BASF.
MasterFlow 9800 possesses a unique combination of features that makes it ideally placed to meet the specific requirements of the project; it combines high strength, low shrinkage properties with the ability to be stored and transported in bulk silos.
FoundOcean proposed the material based on its cutting-edge properties. Sales Director Andy Venn states, Whilst all projects are different and each often presents demands that are specific to its location, design or installation schedule, the offshore wind industry in general faces a number of broader and more fundamental challenges, not least the need to drive down costs. MasterFlow 9800 offers a significant step forward in meeting these needs.
The launch of MasterFlow 9800 in February of this year was the result of three years joint development between FoundOcean and BASF. According to FoundOcean Managing Director Jim Bell, FoundOcean and BASF recognized the demand within the offshore wind industry for a material that could provide high early strength development and low temperature performance, yet also offer increased efficiency, safety and cleanliness.
MasterFlow 9800s ability to be stored in silos rather than bags facilitates quayside storage in all weathers and eliminates the requirement for bag or container lifting during grouting operations and resupply. Moreover, using FoundOcean’s modified Recirculating Jet Mixer, the new MasterFlow 9800 grout system can achieve consistent grout quality whilst maintaining mixing and pumping rates exceeding 20m3/hr, saving valuable offshore operating days.
Grouting for the Gemini Offshore Wind Farm will take place in June 2015.
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