APPLICATION OF THE SECOND GENERATION INTACT STABILITY CRITERIA TO AN INDONESIAN RO-RO FERRY SUPPORTED BY MODEL EXPERIMENT

摘要

The characteristics geometry of Indonesian ro-ro ferries are different with those used to develope the weather criterion in the intact stability criteria of International Maritime Organization. To evaluate the stability of Indonesian ro-ro ferries using the second generation intact stability criteria, an alternative assessment of weather criterion as the vulnerability criteria level 1 is necessary in order to find consistency of each level of vulnerability criteria. This paper discusses about stability evaluation of an Indonesian ro-ro ferry by using the second generation intact stability criteria with the damping factor correspond to the breadth and draught ratio determined by model experiment. The effective wave slope coefficients as function of vertical centre of gravity are calculated using the formula of weather criterion and the simplified strip theory at the wave frequency the same as the natural frequency of roll. The wind and waves characteristics are based on the scatter wave data of a ferry route in Indonesia. As results, the minimum metacentric height for vulnerability criteria level 1 obtained by model experiment is smaller than that obtained by using the values in the weather criterion. The inconsistency between the vulnnerability criteria level 1 and level 2 appears when the values of parameters in the weather criterion are used. However, it shows the consistency when the damping factor correspond to the breadth and draught ratio in the vulnerability criteria level 1 is determined by model experiment. The obtained safety level for the vulnerability criteria level 2 is 0.00008 correspond to the critical metacentric height 1.3 meters. This result show that the minimum safety level recommended by the International Maritime Organization can be applied to Indonesian ro-ro ferries.