Survey of latent hazard of a sunken tanker, Kyung Shin

Presents the survey results of a sunken oil tanker, Kyung Shin, which sank in the East Sea near Pohang, Korea in 1988. Although underwater salvage work for sealing the oil-leaking holes was completed at the time of the accident, small-scale oil slicks near the accident spot have been frequently reported. Accordingly, it is suspected that Kyung Shin is leaking and has the potential to cause a large-scale oil spill in unfavorable conditions. To measure such a risk from Kyung Shin, a survey using an ROV and a manned submersible was conducted for ten days in 2001. During the survey, external inspection using an optical camera was done. A small amount of oil spill from the ship as well as a few hundred-metre scale of oil slick on the sea surface was found. In order to assess the hull´s present corrosion state, hull thickness at a few points was also measured using an ultrasonic sensor. Based on the survey results, it is concluded that there is still a little amount of oil leakage from Kyung Shin but the exact location of the oil-leaking hole could not be identified. Concerning the corrosion status, the hull plate of the sunken tanker has not corroded severely yet. Such a slow corrosion rate is ascribed to the artificial hull coating and environmental factors such as low mean temperature and low dissolved oxygen concentration due to the water depth at which Kyung Shin is located.