CONNECTORS/CABLES/WINCHES;OFFSHORE RENEWABLES

May/June 2007Volume 11 Number 3

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INTERNATIONAL OCEAN SYSTEMS ● May/June 2007 76 May/June 2007 ● INTERNATIONAL OCEAN SYSTEMS

New generation of AHC winch systemsCOVER STORY

Germany and the United States. Eachindependent company has been incorpo-rated to meet the indigenous requirementsof the local area while being fully support-ed by the parent company, MacArtneyA/S, which co-ordinates activities such asproduct development, system integration,training, quality assurance, financial sup-port and marketing.

Underwater technology covers a highlydiverse market which includes: offshore oiland gas geophysical exploration anddevelopment and production; diverse mili-

tary activities, including mine countermea-sures; civil engineering; underwater securi-ty; ocean sciences; environmental studies;and research and leisure activities.

MacArtney’s policy is to deliver triedand tested technical systems solutionsto the problems encountered in thisharsh working environment. Theorganisation is controlled by an estab-lished certified DNV - ISO 9001:2000quality assurance programme, whichwas established in 1993.

The company has shown a sustainable

growth and financial stability over thepast couple of decades and is currentlyrated AAA by the international financialcompany Dun and Bradstreet.

MacArtney employs more than 160qualified people worldwide.

Winch productsA correctly designed cable handling sys-tem can substantially extend the workinglife of most underwater systems; ROVs,towed systems, corers, ploughs, divingsystems and so on. TraditionallyMacArtney has supplied “systems solu-tions”. These are integrated systems ofcables, slip rings, winches, sheaves andlaunch and recovery systems. All systemsare engineered, tested and certified to suitthe customer application.

All winches and cable handling sys-tems are manufactured under controlfrom the headquarters in Esbjerg,Denmark, facilitating co-ordinated engi-neering, design, production, system inte-gration and certification.

One of the objectives of the MacArtneywinch engineering team is to standardisethe winch designs wherever possible,which has proven to be a strong market-ing factor. It cuts costs, shortens deliverytime, standardises spare parts and reducesdocumentation and certification time.However, time has confirmed the Group’scapability of understanding customers’often special requirements for highly pur-pose built systems.

These systems include varieties such assubsea winches, traction systems with10,000-metre cable for offshore pipeinspection that require full ATEX certifi-cation and NORSOK compliance, aswell as all electrical AHC winch systemswith a SWL (safe working load) of up to12 tonnes and a speed of up to 140metres per minute.

Standard products are available in thefollowing categories:● Manually driven winches for deckstorage● Stainless steel electrical winches● Oceanographic winches● ROV winches● Right angle winches● Launch & recovery systems

Most of MacArtney’s winch systems,from the smallest stainless steel winch tothe biggest AHC ROV winch, are electri-cally driven winches. This is a result ofhuge improvements to core technology of

the frequency converters available on themarket today and many years of constantdevelopment work within the Group.

The AHC winch The active heave compensated ROVwinch Oceaneering has chosen for sever-al ROV systems in its fleet is designed foran umbilical of 3400 metres in length and34 millimetres in diameter. It will be usedin connection with Oceaneering’s medi-um to large sized work-class ROV sys-tems, but can also be used for trunkers.

The basic winch design features anincorporated and very compact protec-tion frame, direct drive level wind, vari-able speed, fail safe brake, PLC (pro-grammable logic controllers) control,motion reference unit (MRU) and IP56protection of electrical parts. As with allof the winches from MacArtney, there arefork lift pockets and pad eyes for lifting.

Oceaneering’s AHC winch is the latestgeneration of super high-speed AHCwinch systems with a SWL of up to 12tonnes at cable speeds from 0 to 120metres per minute. The active heave com-pensation is based on input from aKongsberg (Norway) MRU 5, whichforms an integral part of the system. Thisfeature allows for safe and controlleddocking of an ROV into the TMS (tethermanagement system). The time differencefrom input to output in the control sys-tem is extremely short, securing an oper-

ational mode without phase shift.Three powerful electrical motors sup-

ply more than 100 kilowatts of powerthat, through planetary angled gears andan overall ring gear, drives the winch. Allfunctions of the complete winch system,as well as the AHC functionality and awhole string of other control options, aremade available through the highlyadvanced built-in PLC control system.MacArtney is in possession of some ofthe most advanced and complex controlsystems available on the market today.The HMI (human-machine interface)operators panel has an ethernet connec-tion which works as a web server. Fromhere all winch operations can be moni-tored from any computer with internetaccess. PLC programmes can also bemodified and monitored.

As with the majority of MacArtney’swinch designs, the AHC winch incorpo-rates a separate drive for the level wind,which is synchronised with the drumthrough the use of encoders (rotatingcounters) and controlled by the PLC.The quality of spooling with such a sys-tem is unique. Imagine the accuracy ofdividing the rotation of the level windtrapeze spindle into 4096 pulses, com-pared to a conventional diamond spindlewith fabrication tolerance and amechanical gear exchange from thedrum. In most cases this gear exchangeinvolves compromises as the theoretical

As the offshore oil and gas industryincreasingly exploits oil and gasoccurrences at ever greater water

depths and in harsher climatic environ-ments, the requirements put on the tech-nology employed to overcome the chal-lenges of these environments are alsoincreasing. Providers of underwater tech-nology systems and the offshore industryare therefore entering into partnerships inorder to specify and develop new tech-nologies to address the increaseddemands of the market.

The MacArtney Group has been devel-oping and supplying winch systems forthe offshore market for many years.Experience from delivering more than400 winch systems, a dedication to sup-ply smarter solutions and close collabora-tion with the ROV operator industry, hasformed the background for MacArtney’sdevelopment of a new generation of AHCwinch systems.

The new MacArtney AHC winch hasbeen well received by ROV operators,with seven systems delivered since itsintroduction in the autumn 2006 andanother 12 systems in the order book. AnAHC winch was recently delivered toOceaneering AS in Norway. The compa-ny performs a wide range of services forthe oil industry on the NorwegianContinental Shelf and Europe using ROVsystems and underwater technology –from remote construction support andsurvey to drilling and completion sup-port, structural and platform inspectionas well as maintenance and repairs.

MacArtney A/SThe MacArtney Group is a worldwideorganisation of companies specialising inthe sale and service of underwater technol-ogy systems and products. The Group’sheadquarters in Esbjerg, Denmark, estab-lished in 1978, supports subsidiary compa-nies in Norway, Benelux, the UK, France,

The MacArtney Grouprolls out the nextgeneration of activeheave compensation(AHC) winch systems

Three powerful electrical motors drive the AHC winch chosen by Oceaneering

The PLC-controlled level wind

INTERNATIONAL OCEAN SYSTEMS ● May/June 2007 9

COVER STORY

ratio is not possible in reality.The separate drive also allows for a

change of cable diameter when needed(with this system between 31 to 45 mil-limetres). The operator is only required tochange the cable parameters in the soft-ware – as opposed to replacing an expen-sive diamond spindle and gear train.Adjustable turning points for the levelwind at the drum flanges compensate forchanges in the cable’s physical dimensionsdue to wear.

From the HMI operator panel or viaany PC connected to the winch, basicparameters such as load, speed, length ofcable out, remaining cable on the drumand actual layer, as well as cable charac-teristics and alarms and shutdowns, are

available on the screen. The screen lay-out can be altered to suit customerrequirements.

The HMI also allows for interface withother software systems communicatingwith the winch control system. This fea-ture is among others used with theMacArtney FOCUS-2 and TRIAXUStowed vehicle systems, where cablelength, load and cable speed are parame-ters used by the vehicles’ control systemsto control the flight characteristics of theunderwater vehicle.

System optionsSystem options to the AHC system aswell as to all other MacArtney PLC-con-trolled winch systems include wirelessremote control, touch screen remote con-trol station, control of winch by othercustomer signals (i.e. depth sensors) andconstant tension with preset upper andlower values.

The MacArtney PLC control systemmay also, depending on the type of oper-ation, include various operational modes,such as: ● Deck handling (decreased speed rangeon the joystick)● Stop at pre-programmed depth● Emergency recovery

● Automatic stop at eight turns of cableleft on the drum

Other customer specified features aswell as an endless number of operationalstations with safe command transferbetween them are also available.

The AHC winch systems forOceaneering have been delivered accord-ing to DNV Rules for Certification ofLifting Appliances and the electricalinstallation and components have beendelivered according to DNV Rules forClassification of Mobile Offshore Units.

FutureThe new generation AHC winch forOceaneering is one of the most advancedROV winches on the market. TheMacArtney Group continues to developnew winch systems to suit the increasingdemands from the offshore sector. Designcriteria for future winch systems includefaster and more powerful AHC winch sys-tems in order to reduce down time due toweather. Workers’ safety in terms of reduc-ing the noice level and demands for envi-ronment friendly technology are also para-meters. As well as more compact designs,MacArtney’s winch engineers are address-ing in their design efforts solutions toreduce the running costs of the systems. ■

Programming the PLC