PLEASE BE INFORMED THAT fractures have been recently reported in the longitudinals in double bottom and bilge hopper tanks of large bulk carriers of more than 200 meters in length.
This type of fractures have been found in the bottom longitudinals and side longitudinals of high-tensile steel at the following locations :
1. Intersection with watertight floors and watertight bulkheads
2. Connection with stiffeners or brackets on floors and transverse web plates
The fractures propagated toward shell plates. It is reported that a certain ship evacuated as emergency measures because the fracture extended into the shell plate.
The fractures were mainly detected in midship part and found not only in asymmetric section of the said longitudinals such as "L" shaped but also in symmetric section such as "T" shaped in which few fractures had been reported.
The range of ages of the ships which are anticipated to be damaged cannot be specified because of difference in servicing conditions such as navigating area.

For the purpose of preventing serious damages in large bulk carriers, Close-up Survey is to be carried out in accordance with the below-mentioned procedure where ship's length is more than 200 meters and high-tensile steel (HT32, HT36, HT40) is used for bottom longitudinals/side longitudinals in double bottom and bilge hopper tanks.
Please understand our measure to counter the damages and make necessary preparations to perform Close-up Survey.

1. Intermediate Survey
Close-up Survey as comprehensive as Special Survey is to be carried out for the longitudinals during internal examinations of double bottom and bilge hopper ballast tanks.
For ships over 5 years and up to 10 years of age, double bottom and bilge hopper ballast tanks in midship part should be included in "representative ballast tanks" which are internally examined.

2. Special Survey
Special attention is to be paid to the longitudinals during Close-up Survey for double bottom and bilge hopper tanks.
Fuel oil tanks in double bottom or bilge hopper is to be examined in the same procedure.
For ships up to 10 years of age, the longitudinals in double bottom and bilge hopper tanks in midship part is to be included in structural members subject to Close-up Survey.


Please feel free to contact the Survey Department if you need further details or have any question : Tel : +81 3 5226 2027 or Fax : +81 3 5226 2029.

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