Effects of adding sideboard and longitudinal bulkhead construction on ship stability of open-top cargo ship

Abstract

The cargo cover removal on cargo ship will surely affect the technical condition of ship accomplishment that is regulated by rule. In this study, the author would like to evaluate the down-flooding point and free surface effect on open-top cargo ship to the stability acceptance criteria using IMO and DNV test procedures. The simulation result shows that the ship stability value is not in the range of the value required with IMO A.749(18) stability criteria. The failures are caused by lower down-flooding point and free surface effect. The Construction modifications effect by adding sideboard and longitudinal bulkhead is believed can increase the stability value. The simulation result using modified construction shows that the stability value is getting better. Using IMO MSC.Circular608 test procedure, the green-water is still allowed to enter cargo room of modified ship, 633,56 m3 at 25% load, 428,87 m3 at 50% load, and 194.94 m3 at 75% load. It is better than the previous ship that the green-water is not allowed at all. Using DNV test procedure, all of the modified ship stability values are accepted by IMO A.749(18). The value of area 30-40° is 21.06~21.00 m.deg and the value of maximum GZ angle is 28.2°.