Experimental Study on Weather Criterion Applied to South Sulawesi Traditional Wooden Boats

The general stability criteria of International Maritime Organization (IMO) seem to be difficult to apply to the South Sulawesi traditional wooden boats because the down-flooding angle of most traditional wooden boats was smaller than 30 degrees. The weather criterion may be used to assess the stability of traditional wooden boats because limitation of heel angle depending only on the down-flooding angle. However the criterion was developed based on geometric characteristics of ships different from the South Sulawesi traditional wooden boats. In this paper, the hydrodynamics factors correspond to the parameters of weather criterion are determined by model experiments consist of roll decay test and test in regular beam waves. The critical metacentric height for different wave steepness is determined by using the weather criterion with parameters values based on model experiments. The damping factor due to breadth-to-draught ratio was larger than that provide in the weather criterion for corresponding breadth-to-draught ratio of 4.28. The effective wave slope coefficients for wave steepness of 0.004 and 0.006 are smaller than that obtained by the formula of weather criterion. However, a larger value was obtained for wave steepness of 0.008 and 0.01. The bilge keels position with slope of 15 degrees provided the largest damping moment. The South Sulawesi traditional wooden boats comply with the weather criterion when the wave steepness smaller than 0.08. The weather criterion can be applied to the traditional wooden boats if the parameters values of weather criterion formula have been developed.