the 2,404 pound U-joint pin to wrench itself free. On January 17, 1979, it was reported that the buoy was not standing up straight anymore. A diver was sent down to investigate and discovered that the U-joint pin had fallen out. The only thing keeping the buoy from floating away were the jumper hoses bridging the articulation. Three days later, after the buoy sustained more flooding, a diver reported that the buoy was now actually grounding on top of the riser. Recovery operation Alarmed by this news, the owners of the SALM, British National Oil Corporation, immediately notified Chuck Alexander, the project engineer responsible for the 1977 installation of the SALM, and ordered him to mount an emergency rescue of the 340-metric ton buoy before it sustained irreparable damage, or worse, broke free and became a shipping hazard. Alexander flew to Aberdeen, and by the next day he was taken out to the diving support vessel Tender Carrier in the Thistle Field. On board the Carrier, Alexander ultimately decided to have the jumper hoses blown off with explosives. Explosives experts were brought out to the ship with their gear and divers placed clamshell charges around the jumper hoses. On January 23, 1979, the signal was given and Alexander heard a bang and saw bubbles come to the surface. A diver was sent down to have a look and discovered that, although both charges had gone off, only one of the hoses had been cut. With the buoy listing even more precariously, divers undertook the dangerous task of unbolting the remaining hose. Shackles were attached to the top of the buoy, and the buoy was raised out of the water and placed onto the deck of the Pearl Marine. BNOC ordered an inspection of the top of the riser to see if it had sustained any damage. An ROV (Remotely Operated Vehicle—a kind of mobile robot with a video camera) was sent down to make a video inspection, and the report came back that the riser had sustained no damage to it. With the emergency over, the inspection tape was mailed to Alexander in London. Several weeks later, Alexander viewed the tape and discovered that one of the clamshell charges had blown a big hole in the top of the riser. The explosion had also rocked one of the 16-inch flow lines out of its clamps, displacing it 30 feet below