[WRE UPDATE | PRODUCT]
A CUTTING-EDGE SUBSEA LIFT DEVICE
THE CLAW: BY: CASSIE SCHOTT T Photo A
he development of Versabar’s Bottom Feeder lift system was a breakthrough in off shore salvage operations in 2007. Designed and built in response to the large number of platforms toppled by hurricanes into the Gulf of Mexico, the Bottom Feeder’s ability to
perform single-piece topside retrievals provided a safe and effi cient alternative to time-consuming and hazardous piecemeal recovery. T e demand from off shore operators for a larger, more robust system that could handle heavier lifts and also perform above-water platform decommissioning prompted Versabar to build a second system. T e VB 10,000 was completed in a 12-month span and launched in October 2010 as the largest lift vessel built in the United States. After retrieving dozens of sunken platforms with the Bottom Feeder and VB 10,000 lift systems, Versabar engineers found themselves with a new set of challenges. In a number of cases, the sunken topsides were too fragile to remain intact during the lift to the surface. Versabar engineers designed and fabricated large steel “baskets” with multiple lift points to assist in these lifts. Lowered to the sea fl oor adjacent to the damaged structures, these baskets would then provide a stable base to enable the damaged topside to be retrieved intact (Photo A).
NEW LIFTING TECHNOLOGY
As subsea work progressed, another safety issue presented itself. Sending divers to the sea fl oor to attach hooks to unstable structures, often in poor visibility with swirling currents, meant uncomfortable levels of exposure for off shore operators. Challenged to remedy the situation, Versabar President Jon Khachaturian came up with a solution that would require minimal subsea preparation in topside retrievals: a new lift device that would eliminate the need for using hooks as lift points. Named, “T e Claw,” the new device would scoop up the sunken topsides from the sea fl oor, and deposit them on baskets to be retrieved using the VB 10,000 lift system.
T e Claw project began in December 2010 with a series of rough sketches as Khachaturian communicated his concept to his team of engineers and draftsmen. T e draftsmen then went to work to produce a series of drawings that would evolve into the fi nal documents that fabricators would use for construction. T e Claw design consists of two identical grappling devices suspended from each of the gantries of the VB 10,000. Each Claw is made up of two halves, joined at the top by a pin connection to a girder. Each Claw girder is attached to the VB 10,000 by two 3.5” 9-part x 40’ slings (Photo B). T is sling connection allows the Claw to easily attach to the VB 10,000, and detach for lift operations when it is not
Photo B 72 JANUARY-FEBRUARY 2012 WIRE ROPE EXCHANGE
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