A police dive supervisor told an inquiry how he arrived at the scene of a boating tragedy to find no one had marked the location.
Kenneth Freeman, 43, told a Fatal Accident Inquiry at Oban Sheriff Court location instructions were vital as it would take 18 months to search the whole of Loch Awe, which was last charted in 1894.
Glasgow men Craig Currie, 30; Thomas Douglas, 36; William Carty, 47; and Stephen Carty, 42 died, after their boat capsized in the near-freezing waters of Loch Awe, as they headed to a shoreside camp after a night out at the Tight Line pub.
William Carty and Mr Currie were retrieved from the fog-covered loch shortly before the dive team arrived. The bodies of Stephen Carty and Thomas Douglas were washed up by a loch island two months later.
The hearing continues.