Big claw makes marine salvage operations faster, safer and less expensive
Trelleborg, Sweden - Watching the VB 10000 in action is quite a sight. Four giant white C-shaped truss structures with prongs at the bottom, dubbed “the Claw,” hang below two massive yellow arched trusses, spanning a pair of barges...
Trelleborg, Sweden – Watching the VB 10000 in action is quite a sight. Four giant white C-shaped truss structures with prongs at the bottom, dubbed “the Claw,” hang below two massive yellow arched trusses, spanning a pair of barges measuring 22 by 88.5 meters (72 by 290 feet). The Claw is designed to reach hundreds of feet below sea level to remove sunken oil rigs from the seabed, in one piece and in one day. It’s also designed to lift the heaviest of loads. Although most oil rigs weigh between 1,000 and 3,500 tons, the VB 10000 can lift 6,000 tons in its current arrangement, and when in double grapple configuration it can lift as much as 10,000 tons.
“It’s a game changer,” says Paul Van Kirk, project engineer with salvage specialist Versabar, which built the Claw. “The industry has never seen anything like it. We can now retrieve platforms that have been knocked over by hurricanes without sending divers down to rig them up. That saves time and money.” The Claw made its debut late in the 2011 lift season and performed five of the 40 lifts during that season. Its success has brought an increasing number of lifts for the busy 2012 salvage season, which runs from May through November, says Van Kirk.
Versabar took just eight months to engineer, fabricate, test and deploy its new underwater heavy-lift vessel. The two massive steel gantries, each weighing 1,000 tons, are designed to work solo or in tandem, depending on the type of object on the seabed. The Claw is optimized to require as little underwater preparation by divers as possible, reducing both costs and risks to humans. That’s why the industry’s Offshore Technology Conference in Houston, TX, awarded the Claw its Spotlight on New Technology Award for 2012.
The materials used for bearings in several key locations are a significant part of the vessel’s innovation, says Van Kirk. Its predecessor, the smaller VB 4000, originally used bronze bushings in the critical hinged gantry and barge connection. The bushings required regular maintenance for lubrication, wore out quickly and made a lot of noise. “When we started the design process for the VB 10000 we knew we wanted to use Orkot,” the Versabar engineer explains, referring to a composite material developed and manufactured by Trelleborg. “It’s maintenance-free, easy to install, flexible and quiet. It just has a good track record.”
The VB 10000 uses Orkot material for its bearings in the gantry and barge connections and the sheaves in the blocks used to open and close the Claw. “The material is perfect for the job,” says Jason LaBorde, Sales Engineer with Trelleborg, who worked closely with Versabar’s engineers to get the heavy lifter built. “Orkot is designed for heavy loads and slow movements in a seawater environment. It’s both resistant to UV rays and corrosion.”
Incorporating the material into a new device was a speedy and efficient process, both engineers agree. LaBorde credits Versabar with being “the fastest-moving engineering company I have ever dealt with.” The Houston-based company defined the load and other specifications for the VB 10000 and the Claw. Trelleborg’s experts provided design input and airlifted the finished bearings to the assembly site on the Gulf Coast. “They were very responsive in helping us finalize our design quickly,” recalls Van Kirk. “Trelleborg gave great support after shipping the parts, assisting in their installation.”
The Claw retrieves knocked-over platforms without the help of divers
Founded in 1981 by civil engineer Jon Khachaturian, Houston-based Versabar is the world leader in developing and deploying heavy-lifting solutions. The company has 700 employees in the Gulf of Mexico region and serves a portfolio of international clients, meeting their lifting needs on land and sea, including technically challenging underwater salvage operations to remove old oil-drilling platforms.
Orkot® is a lightweight and durable composite material developed by Trelleborg and is used in a wide variety of industries. Being specially formulated for use in sea water, the material is ideal for the shipping and marine industries. The bearings are integral to various applications, including crane masts, rudders, stabilizers and gantries. They have a load capability comparable to metal bearings but are virtually maintenance-free and as they do not need lubricant to operate, are fish-friendly.