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Lookup NU author(s): Dr David Trodden
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Every year, a significant number of fatalities occur aboard small ships, particularly small fishing vessels (SFVs). The primary contributing factors include buoyancy deficiency, insufficient stability, and the absence of a stability standard. During the 2018–2021 timeframe, this type of boat was involved in 31% of ship accidents in Indonesia. Since traditional Indonesian SFVs are built using skills passed down from generation to generation, boatbuilders disregard engineering and safety considerations. On the other hand, the existing intact stability criteria might be inapplicable to traditional SFVs because their down-flooding angle is commonly less than 40 degrees or even less than 25 degrees. This study assesses the stability performance of a typical SFV in various down-flooding angles derived from the loading conditions towards intact stability and SGISC, namely dead ship condition and pure loss of stability. The results show that a small down-flooding angle has a considerable influence on the area under the curve in terms of the stability area boundaries, which makes imposing this requirement on the SFVs inappropriate. This vessel also does not comply with the dead ship condition due to the considerable angle of roll to windward (φ1), despite the fact that the steady and gust wind heeling levers are relatively small due to the low wind pressure. When this angle is significant, the a area's borders becomes even larger. This is affected by damping parameters such as the B/d ratio (X1), the block coefficient (X2), and the bilge keel (k). Furthermore, the rolling period of a small ship results in a high wave steepness factor (s). Proper values for the X2 and s factors are necessary to obtain the appropriate factor for the lower block coefficient and rolling period kept by SFV. Besides that, a small down-flooding angle has a crucial part in limiting the b area to be smaller. Moreover, the steeper decline of SFV's round hull resulted in a low transverse moment of inertia, which influences the low value of GM for both intact stability criterion and dynamic stability addressing pure loss of stability vulnerability criteria. Finally, based on this study, a high number of SFVs accidents during last years may be involved due to poor dynamic stability of dead ship conditions and pure loss of stability.
Author(s): Setiawan W, Trodden D, Hu Z
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: The 2nd International Conference on Marine Research and Technology (ICOMAREST)
Year of Conference: 2023
Print publication date: 18/10/2023
Acceptance date: 02/04/2023
Publisher: ICOMAREST
