200218 Grappling with an Anchor
Grappling with an Anchor
Report No. 200218
Whilst working on a support vessel in the Gulf, we experienced several incidents in one 24 hour period. After initially being requested to assist the US Navy in a Search and Rescue operation, we were requested to go to the aid of two persons on a barge. After that we were called to a tanker which was, apparently, fully loaded with 1,000 tonnes of crude oil and had been abandoned by its crew after it had been anchored in the United States inspection area for ships heading to or from Iraq. We found that it was completely blacked out, lying to its port anchor with an unknown amount of anchor chain out. The wind was now northwest and blowing at 35+ knots, a sandstorm had reduced the visibility to 0.5nm or less.
Our vessel was directed to "get a line" onto the tanker. This was easier said than done, the sea prevented anybody boarding the tanker and so I decided to try and get a wire around the anchor chain and "chase it". We made a number of attempts to carry this out but due to the high seas that were running, the sandstorm reducing visibility and darkness it was impossible to hold still enough for the crew to get a line around the chain. I eventually called off the attempts due to the danger to the crew and decided that the only way to make connection was for us to grapple for the tanker's anchor chain. However, due to the small size of the chain, there was a danger that the grapple, which was for Oil Rig anchor chain, may break the tanker's chain and cause the drift to increase in speed. Additionally, I was concerned that if we broke the chain and the tanker consequently went on to cause damage and pollution then my actions may have been held responsible.
We started to rig the grapple but after a short time it was decided to stop rigging it due to the danger to the crew caused by seas boarding the after deck and to see if it was going to be necessary to carry out grappling as a last resort. We had previously been fitted with precision navigation equipment for a "Rig Move" that was due shortly and we started to run up and down very close to the tanker to provide information of the tanker's position with regard to the rig. The equipment was such that the rig could see on their system our exact position at all times. After a short while, the plot of the tanker's drift showed that it would either collide with the rig or with another rig that was jacked up at the same wellhead platform. The Emergency Team ashore was mobilized and the American warships in the area were monitoring the situation by our VHF conversations. We continued to monitor the tanker's drift and it was ascertained that she would probably miss the jack up rig but collide with the other rig. All wells were shut down and a helicopter scrambled to assist in evacuating the rigs.
At 0314 the next morning we were asked to continue to rig our grapple. In order to do this I had to "heave to" our vessel in order to make the after deck safer for the crew. Even though we were "hove to", the seas were still breaking over the after deck and the crew did a magnificent job in rigging the equipment in what were extremely dangerous conditions. While we were preparing the grapple the main rig put out a Mayday call over the radio as the situation was becoming extremely tense. Once the grapple was prepared we turned and raced back to find the tanker. At first we could not locate her as the sandstorm was effecting visibility and other ships approaching the position in answer to the distress call were complicating the radar picture. We eventually located her a lot closer to the rig than had been anticipated and we were instructed to abandon giving "fixes" and to grapple the anchor chain immediately. Meanwhile it had proved impossible to evacuate the rig crew in the short time available.
On our first pass at grappling, our starboard quarter came into contact with the port bow of the tanker and the grapple failed to connect with the chain so I turned around as fast as was possible as time was against us and unfortunately the tow wire that we had attached to the grapple slipped from the stern and ended up over our port side. The situation was urgent so I continued to attempt to grapple the chain and on our next pass we passed the tanker's bow so close that the starboard Kort Nozzle around the propeller came into contact momentarily with the tanker's anchor chain. We persevered and this time the grapple caught the chain. We only had contact with the tanker for a short while as the strain pulled all the tanker's anchor chain out of the locker. Evidently they had not applied stoppers on the chain prior to abandoning the tanker. Our short contact however proved crucial as it was found that we had managed to pull it sufficiently far so that it missed the rigs by a very small margin.
On heaving up our grapple we found that we had the tanker's anchor chain still attached. As it was hanging over our port side there was no way that we could recover it onto our deck so we were now forced to steam up and down, keeping clear of pipelines on the sea bed until the weather calmed sufficiently to use the rig's crane to help us re-position the grapple wire over our stern. Twenty four hours later, after dragging the anchor and chain along the sea bed with the rig crane's assistance we were able to recover the grapple to our deck, the tanker's anchor and all of its chain. She continued drifting for two days being chased by various tugs, none of which were able to make connection. After two days a salvage tug finally connected to the tanker and towed it to a port.