He survived 60 hours in an air pocket on the seabed

Harrison Okene, the cook on the tugboat Jascon 4, spent almost sixty hours alive inside a pocket of air thirty metres down, off the coast of Nigeria. The boat capsized on 26 May 2013 while steadying an oil tanker, and of the twelve crew he was the only one who got out.

Okene was in the bathroom when the tug rolled over. He swam blindly through corridors that now had their ceilings underneath him until he wedged himself into a gap in the officers' cabin where the trapped air had not yet escaped: a pocket barely a metre high, pitch dark, water up to his waist, in his underwear. He tore a panel off the wall to sit on so the metal wouldn't drain his heat. He had no torch, no drinking water, no way of knowing the time.

Two and a half days later a team of divers came down, hired to recover bodies, not survivors. One of them reached into the hull, touched what he took for a corpse, and felt the hand close around his own. The helmet camera recorded everything, and the video went round the world that summer.

The final tally has an uncomfortable symmetry. Because he had been breathing pressurised air for some sixty hours at thirty metres, he had to be put in a hyperbaric chamber for another sixty hours and decompressed slowly: the same time to survive as to be allowed back to the surface. The eleven bodies of his crewmates were recovered over the following days.