Life on the most remote inhabited island in the world

Oil rig update

Titan makes 1st refloat attempt on 3rd February

(with thanks to Richard Grundy of www.tristandc.com)

The salvage team made a first attempt on Saturday 3 February to refloat the oil rig stranded at Trypot Bay.  However, although there was plenty of buoyancy on the port side of the rig, the tides were not sufficient to lift the starboard side clear of the reef.

The main attempt to refloat is still scheduled for mid-February, and the team will be working hard until then to regain some more of the buoyancy they need.

listing-oil-rig-2.JPG  listing-oil-rig.JPG  oilrig8june06.jpg

The photographs (first two) show clearly (compared with the situation in December – photo at the end) how much of the structure has been cut away to remove weight to assist the salvage attempt and the amount of buoyancy obtained, particularly on the seaward size of the rig, where the previous waterline mark shows how much further the support columns have lifted out of the water.

Pressure Tides and Winds
The Titan salvage team will be aware that during anticyclonic weather and the accompanying high pressure, sea levels are lowered by the increased weight of air – about 1cm for every mb of increased pressure. So it is not only the high tide on 18th February, but the air pressure, which will determine the exact level of the ocean. Ironically it would be better to be lower pressure (with the likelihood of stronger winds) rather than a calm anticyclone which could raise the high tide by a crucial few extra centimetres. Perfect would be low pressure with a north-west wind (the prevailing wind on Tristan) so that Trypot Bay would be in the lee.
It’s an ill wind……. (note from Web Manager Richard Grundy)

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Comments on: "Oil rig update" (3)

  1. Bob Conrich said:

    What has the salvage team done with the parts they’ve cut away? I hope these folks are being monitored so that they won’t be tempted to use Trypot Bay as a rubbish tip.

    I have seen this sort of behaviour here in the Caribbean, with the salvage master telling the press he was doing us a favour by creating an artificial reef. An artificial reef is not a bunch of rubbish dumped overboard.

    Bob

  2. Hi Bob, Erik & Claire,

    Tristan Times says”dumped in deep water.” The dropoff at TdC is near-shore so they didn’t have to go far.

    http://www.tristantimes.com/art_3878.html

    Weekly News from Tristan

    On the 3rd February, the Fishery Patrol Boat Wave Dancer and the Police Rib Atlantic Dawn with a team of observers and the island Administrator went to Tripot Bay to watch the 1st attempt to refloat the oil rig.

    Over the past few weeks the salvage team had been busy cutting and removing as much material from the rig as possible to try and make her lighter for the tow, approximately 600mt had been removed and dumped in deep water.

    It was an excellent day, and although the rig had good buoyancy on the port side, the tides were not sufficient to lift the starboard side, which had become damage during the early part of the attempt.

    It is the intention, if all goes to plan, to try the main refloat in the next week or two. In the meantime the salvage team will be putting more air bags in the columns to achieve as much buoyancy as possible.

  3. For better accurate and up to date info about Tristan, tristandc.com is a better site.
    And you can have the last news about the oil rig, which finish its life yesterday morning, with the final attempt of the salvage team.
    It’s here : http://www.tristandc.com/newsofPXXI.php#bottom

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