Thesis
Dynamic performance of small fishing vessels in waves with varied loading conditions
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2024
- Thesis identifier
- T17092
- Person Identifier (Local)
- 202151102
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The widespread occurrence of accidents involving fishing vessels is an important issue that needs to be addressed by the maritime community. Most of these accidents involve small fishing vessels. On the other hand, small fishing vessels can support sustainability in fishing by preventing overfishing, unlike the large-scale fishing industry. In Indonesia, the government aims to enhance food security through the maritime sector by providing fishermen with many small fishing vessels. Therefore, research on enhancing safety for fishing vessels is essential. This thesis explores this topic by investigating the dynamic performance of small fishing vessels in waves under varied loading conditions. Fishing vessels operate in different areas. With the same hull form and loading conditions, the dynamic responses of the fishing vessel vary. Therefore, an operability assessment is required to determine the seaworthiness of the vessel in a given area. There are eleven fishing management areas in Indonesia. This thesis focuses on the Java Sea as the operational area for the investigated fishing vessels. A new methodology is developed to assess a single operability index for a single fishing vessel, applicable across multiple loading conditions. A case study assessing a single operability index for three different sizes of fishing vessels provides recommendations of the appropriate vessel size for operations in the Java Sea. A detailed investigation into stability in waves is conducted, centring on parametric roll, a type of stability failure highlighted by the International Maritime Organization (IMO) using Computational Fluid Dynamics (CFD). It is discovered that small fishing boats can experience parametric roll, in contrast to previous understanding of the phenomenon. The GM ratio, that is, ratio between the amplitude GM in waves and the GM in calm water, is not only an indicator of the magnitude of the parametric roll amplitude but also of the heave and pitch amplitudes for the same hull form and displacement. This discovery is subsequently used to develop a novel optimisation methodology. Radius of Gyration in the Y-Axis (Ry) is identified as an effective indicator to determine heave and pitch amplitudes in head waves. A minimal Ry results in a lower moment of inertia, which increases the pitch damping ratio and subsequently reduces the pitch amplitude. Both GM ratio and Ry are straightforward to calculate and require no functional evaluations that are costly or time-consuming. These parameters can be used to indirectly assess seakeeping performance and are suitable as objective functions in seakeeping optimisation, helping to accelerate the optimisation process by an order of magnitude compared to existing practice. Hydrodynamic optimisation can be an effective way to enhance ship performance, either by improving seakeeping and stability in waves or by minimising total resistance to reduce carbon footprint, promote decarbonisation, and lower fuel consumption. A new methodology based on the aforementioned indicators is developed in hull form optimisation, enabling the simultaneous minimisation of total resistance and dynamic responses at sea, thereby avoiding the need for multi-objective optimisation. The hull form is optimised to achieve minimal total resistance, and during this process, the longitudinal centre of gravity (LCG) and vertical centre of gravity (KG) of each hull form variation are adjusted to achieve minimal Ry. As a result, the optimal hull form achieves both minimal total resistance and minimal dynamic responses.
- Advisor / supervisor
- Terziev, Momchil
- Tezdogan, Tahsin
- Incecik, A.
- Resource Type
- DOI
Relations
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PDF of thesis T17092 | 2024-11-25 | Public | Download |