• China Ocean Engineering Shanghai Company (COES)

    Sewol Ferry Wreck Recovery in One Piece

    Offshore Mokpo, Yellow Sea, Gwangju, South Korea

Project Summary

Project

More than a year after the sinking of the Sewol Ferry in April 2014 that killed 304 passengers and crew members, efforts began to recover the ferry boat wreckage. The tragic accident occurred in the Yellow Sea off the South Korean coast. The Ministry of Oceans and Fisheries contracted China Ocean Engineering Shanghai Company (COES) to raise the 6,825-ton vessel from a depth of 44-meters within a tight one-and-half-year timeline. The ministry required the organization to salvage the craft in one piece without damaging the hull and ensuring that the remains of nine victims still onboard stayed in the hull. In addition, COES had to work during the winter and negotiate the sea’s strong current and high waves, which made conceiving an engineering solution even more difficult.

Solution

Since a shipwreck recovery operation is of similar scope to an offshore platform installation, COES applied subsea lifting engineering techniques that included deploying two barges on either side of the wreck with the ferry in the middle, lifting the wreck from the side and floating it on a semi-submerged ship. The team used integrated offshore simulation software to model how the team would lift and moor the vessel. It also had to devise a plan to transport the ferry on a semi-submerged ship and unload it onto shore. The design called for inserting 33 beams under the wreck by using floating cranes to lifting the bow and insert the beams. Additionally, the team used the application to conduct numerous analyses that improved engineering efficiency and accuracy.

Outcome

The project team’s use of integrated offshore simulation software resulted in the world’s first recovery of a shipwreck in one piece. The process enabled COES to save 1,000 total engineering resource hours a week and deliver the project on schedule, while saving USD millions per month. The operation meant that the team could recover the remains of the nine onboard victims, as well as meet the Korean government’s environmental requirements and economic viability. The solution is now frequently used to recovery large shipwrecks in one piece, including a large derrick barge raised from the bottom of the Gulf of Mexico and transported to land in February 2019.

Software

The team used MOSES software to conduct several analyses that improved engineering efficiency and resolved various clashes related to the project solution. MOSES software enabled the team to visualize the three vessels and perform lifting and mooring analyses. The software also enhanced the accuracy of hydrodynamic calculations. Moreover, MOSES helped the project team reduce the number of engineering hours that were spent on the comprehensive marine operation, keeping the project on track to meet the timeline mandated by the South Korean government.

Project Playbook: MOSES

Outcome/Facts
  • The Ministry of Oceans and Fisheries contracted China Ocean Engineering Shanghai Company to raise the Sewol Ferry within a tight one-and-half-year timeline.
  • MOSES software helped the team conduct numerous analyses that improved engineering efficiency and accuracy, allowing the ship to be raised in one piece and the timely recovery of the victims’ remains.
  • MOSES reduced engineering hours that helped the team meet the aggressive timeline mandated by the South Korean government.
Quote:
  • “After our innovative solution was first practiced and proved in the Sewol recovery project in early 2017, this solution is used in offshore industry frequently for large shipwreck recoveries in one piece. This solution is further proved as the best wreck-removal method in terms of environmental friendliness, as well as engineering and economic viability.”

    Zong Yao Senior Engineer China Ocean Engineering Shanghai Company