A rescue diver from the Korean Navy's Ship Salvage Unit goes into the water, with hopes of finding survivors, or the bodies of the fallen.
Under the surface, their visibility is limited, pitch black really,. save for an area about 20 centimeters in front of the divers' faces.
The situation worsens at night.
Despite the help of flares and lighting from fishing boats, divers can barely see, relying instead on distance lines, or guide lines.
Those lead them inside of the sunken ferry, and then back to safety.
There are hundreds of Navy and private divers on the scene,. but each guide line can only be shared by two divers.
In the early hours of rescue operations, just three or four divers were able to get into the water because just one or two guide lines were set up.
High waves and strong currents also hampered the rescue operations in the first 48 hours after the accident, which is the so-called golden time for rescue operations.
After numerous failed attempts, divers finally got inside the ferry, on the fifth day of the tragic accident,. with the help of five guide lines that were set up.
With tidal currents and waves calming this week, search operations have accelerated.
However, divers are still at risk.
They face the risk of decompression sickness, known as divers' disease, which took the life of a Navy diver who was participating in search and rescue efforts following the sinking of the warship Cheonan four years ago.
Despite such risks, rescue divers continue to go into the water, with faint hopes of finding a survivor, even though it's now been days since the ferry sank.
Park Ji-won, Arirang News.