Chris Lemons and the rest of the crew aboard the Bibby Topaz had a simple mission. At least, it should have been simple for a team of such experienced divers. Their vessel was to plunge deep into the North Sea, following which Lemons, Dave Yuasa and Duncan Allcock would step into an even smaller diving bell to take them further down beneath the waves.
And after the team had dived 300 feet down from the bell, Lemons and Yuasa then began repair work on a damaged pipe while Allcock manned their vessel. Yet while the start of the men’s mission had gone off without a hitch, it wouldn’t stay that way for much longer. Alarm bells started blaring, alerting the crew overhead that the Bibby Topaz’s navigation system had malfunctioned.