Local contractors help Coast Guard reposition Crescent City navigation buoys

CRESCENT CITY, Calif. - Contract workers aboard the fishing vessel Twin Sister reposition a navigation buoy off the coast of Crescent City Thursday, March 31, 2011. Navigation buoys were moved as far as 300 yards off course by surges from a tsunami that hit the Northern California coast Friday, March 11. U.S. Coast Guard photo by Petty Officer 3rd Class Kevin Metcalf.

Coast Guard photo by Petty Officer Kevin Metcalf

ALAMEDA, Calif. — U.S. Coast Guard personnel assisted and provided oversight to local contractors from Crescent City, Calif., during a multi-day evolution as they repositioned the number six and seven navigation buoys March 30-31, 2011.

The Coast Guard contracted MM Diving & Salvage and the fishing vessel Twin Sister to reposition navigation buoys that were moved more than 300 yards off course from charted positions by the tsunami that hit the Northern California coast March 11, 2011. MM Diving crews attached large air bags to the 13,000 pound cement blocks, used to anchor the buoys in position. The Twin Sister then towed the buoys back into place using GPS coordinates provided by the Coast Guard.

Coast Guardsmen from the Coast Guard Cutter Aspen, a 225-foot sea-going buoy tender homeported in San Francisco, and crewmembers from the Coast Guard Cutter Dorado, an 87-foot Coastal Patrol Boat homeported in Crescent City, assisted in the evolution.

The Crescent City Harbor was closed to navigation for a period due to the tsunami, but because of backup range markers that were still in place, the harbor was reopened to navigation sooner. Due to the duplication in navigational resources, the buoys were not as critical to the safety of transiting vessels as they may have been without the range markers.

An aids to navigation system is a group of interacting external reference devices intended to collectively provide sufficient and timely information with which to safely navigate within and through a waterway when used in conjunction with updated nautical charts and other commonly available material. Mariners are encouraged to notify the Coast Guard whenever they notice a discrepancy with aids to navigation.

When mariners report a buoy off station or a light inoperative, the public is notified via broadcast notice to mariner radio messages. The primary and secondary Coast Guard units are then notified and coordinate a plan to correct the discrepancy. After the aid is corrected, the mariners are notified again, via radio messages, that the aid is watching properly.

The Coast Guard operates, administers and maintains the U.S. Aids to Navigation System, which includes buoys, day beacons, and lights, and updates mariners on immediate changes in aids to navigation reliability.

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