Mitsui OSK Lines (MOL) is planning to withdraw from service the six sister vessels of MOL Comfort, which broke in two and partially sank in the Indian Ocean on 17 June 2013, in order to upgrade them.
The six vessels include MOL Creation, MOL Charisma, MOL Celebration, MOL Courage, MOL Competence and MOL Commitment.
The company said in a statement that they have decided to take extra preventive measures on the six sister vessel as the cause of the sinking of MOL Comfort will take some time to identify.
"For the six sister vessels that we operate, we have already started the operational precautions to reduce the stress on the hull", the statement added.
According to MOL, the six sister vessels comply with the safety standards required by the classification society Nippon Kaiji Kyokai (ClassNK) in accordance with the International Association of Classification Societies (IACS), and the company intends to carry out upgrade works to further improve the strength of their hull structures.
MOL, along with Mitsubishi Heavy Industries (MHI) and ClassNK, is currently continuing the investigation into the cause of the MOL Comfort incident.
When the incident occurred on 17 June, the 2008-built vessel was carrying 4,500 containers along with 26 crew members, including 11 Russians, one Ukrainian and 14 Filipinos, all of whom were rescued.
About 1,700 containers on the aft part of the ship sank, while the fore part is being towed with the majority of cargo aboard towards the Arabian Gulf.
The company is also keeping patrol boats in the area where the aft part sank in order to monitor oil leakage and floating containers.