ROVworld Subsea Information

Global Marine System's Pacific Guardian uses new cut and hold grapnel for deep w
Date: Tuesday, October 28, 2008 @ 15:00:00 EDT

Global Marine System's Pacific Guardian uses new cut and hold grapnel for deep water repairsRecently, the Pacific Guardian undertook a deep water cable repair operation off the U.S. continental shelf in about 4500 meters depth of water, repairing a cable that was damaged by another cable ship that was carrying out a repair on the Gemini cable system.

The cable system configuration constraints coupled with a limited availability of spare cable meant that it was essential for GMSL to insert a minimum of new cable into the system for this complex repair.

Traditionally, on a deep water repair, a conventional cutting drive would be followed by a 2nd holding drive undertaken at 2 x depth of water further down the cable line. This is done to ensure that once the cable is hooked there is sufficient weight of cable over the grapnel to keep it from falling off the grapnel when the pick up is carried out. In this case it would have meant losing approximately 9 kilometres of cable.

While a tentative plan was put in place to freight supplies from UK to Bermuda, an experienced and competent team composed a precise repair plan that utilised the new GMSL cut and hold grapnel.

The cut and hold grapnel worked the first time and was able to cut and recover the cable to the surface in one attempt . This was repeated for other sections of the cable, the vessel carried out 3 grapnel drives and each one was right first time. Saving the extra cable it also saved about 24 hours of down-time. Without this method, it would have been impossible to complete this operation with the cable available, and the customer would have had at least an extra 2 weeks of operational downtime until the network was restored. It also avoided the direct cost of freighting extra cable across the Atlantic.

This article comes from ROVworld Subsea Information

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