Operations - Survey

A Survey Vessel is used to find the target wreck. SubSea's ship is the John Lethbridge which has a gross tonnage of 1,835 tonnes and is 75 metres long. It has Lloyds Certification and is equipped with the following:

• Dynamic Positioning (so the ship does not require an anchor to hold it in position and can therefore operate in very deep water);
• GPS (Global Positioning System) navigation which can be used to position the ship to within a few metres anywhere at sea;
• Side Scan Sonar (depth-rated for 6,000 metres) which is "flown" just above the seabed, scanning up to 2000 metres on either side of its path enabling a position of an object to be fixed within a few metres. Coverage is up 4 square miles per hour;
• ROV (Remote Operating Vehicle) to enable a visual inspection to be made providing confirmation of the target and identification for analysis of size and relative position of superstructure, mast and hatches.

Wreck location can take just a few days although the Group generally budgets for 15-30 days on site for the survey vessel for location purposes depending on the size and difficulty of the search area.