§ Mr. Hooleyasked the Secretary of State for Defence what proportion of the United Kingdom Continental Shelf has been covered by surveys using modern echo sounders at acceptable scales and including modern sonar sweeps to establish the least depth over all wrecks and obstructions.
§ Mr. DuffyAbout 26 per cent. of the United Kingdom Continental Shelf has so far been surveyed with echo sounder and sonar sweeps. About 5 per cent. has been covered by modern sonar sweeps.
§ Mr. Hooleyasked the Secretary of State for Defence how many wrecks are known or thought to exist on the United Kingdom Continental Shelf whose position and least depth are at present not accurately known.
§ Mr. DuffyAbout 14,000 wrecks are known to exist on the United Kingdom Continental Shelf. About 3,000 have been located accurately, but the least depth is known accurately over fewer than 1,500.
§ Mr. Hooleyasked the Secretary of State for Defence what proportion of the United Kingdom Continental Shelf has either never been surveyed or is only covered by hand-lead and line surveys; and how many ship-years of work would be required to cover this area to modern standards.
§ Mr. DuffyAbout 74 per cent. of the United Kingdom Continental Shelf has not been surveyed by echo sounder or sonar. It is estimated that between 250 and 300 ship-years of work would be required to bring coverage of these areas up to the highest modern standards.