SAN DIEGO – In March of this year, the San Diego Bay Approach Lighted Whistle Buoy San Diego was reported missing and Coast Guard divers used side scanning sonar to confirm that it had sunk on station. In August, the buoy was recovered.
In August, the Coast Guard announced that it would attempt to recover the buoy on Aug. 6 to 7 and deliver it to the Coast Guard buoy facility in San Francisco for repairs. The Coast Guard planned to set a temporary buoy on station until the permanent buoy has been repaired and reset. The temporary buoy will not have a RACON or whistle sound signal.
According to the agency’s latest update, prior to the Coast Guard’s arrival in San Diego, Coast Guard divers dove down and confirmed that the buoy was still attached to the chain and sinker. The original plan was to work with the divers to recover the buoy – they would dive down and attach chain to buoy and use lift bags to float it up on the surface, then Coast Guard officers would haul the chain up and, along with it, the buoy and the mooring.
“Unfortunately, the current was too strong for the divers to safely operate, so we had to recover the buoy the old fashion way – by dragging,” explained Lt. Stephen Brickey, commanding officer for Coast Guard, George Cobb.
Lt. Brickley explained that they hung a grapnel, which is basically a large multi-pronged hook, over the side of the ship, dragging the grapnel along the sea floor, hoping to hook into the chain of the mooring.
“We were lucky in that we had the images from the side scanning sonar, so we had a pretty good idea of where the chain was stretched out,” he wrote. “We drove the ship over where we think the chain is, going slow so that the grapnel doesn’t skip across the bottom, and once we feel it ‘bite’ we start reeling it up. Sometimes this takes numerous passes – we were lucky to snag something on the first try. This is the exciting part, because until the grapnel gets to within 20 or so feet from the surface, you can’t be sure what it is you’ve hooked in to – you hope for the chain, but it could be the cage of the buoy, the sinker, or something else entirely – I’ve heard stories of ships pulling up old cars.”
Luckily they hooked in to the chain
The deliberate process included securing the chin to the deck, cutting the chain and pulling up each end separately.
“The first end we pulled up was attached to sinker, which we secured to the deck. Pulling up the buoy was more interesting – our crane has a working load limit of 20,000 pound, however a flooded buoy weighs over 33,000 pounds,” Lt. Bickley explained. “We were able to pull the buoy out of the water enough that we could use a plasma torch to cut some holes in it, letting the water drain out and reducing the weight. After we recovered the sunken hull, we placed a temporary 8×26 on-scene for the mariners.”
The sunken hull will be taken to the buoy yard and refurbished, and will eventually be back out off of San Diego