Vessel operations in relation to new types of offshore aquaculture facilities, and weather windows in exposed areas

Abstract

The marine aquaculture industry is expanding the production into new sea areas. The technology is advancing, and offshore aquaculture facilities are being developed. The offshore developments can offer significant benefits that applies to the economy, optimization of operations and production, as well as minimizing the impact on the coastal areas. Structural and operation procedures need to be adapted as a result of transitioning from traditional production sites. Offshore aquaculture facilities are large rigid structures which leads to new challenges due to environmental parameters and dimensions. The field is rather unexplored compared to offshore wind or oil and gas industry. A dynamic analysis is conducted to study the response of the conceptual aquaculture facility ØyMerd. A 3D model of the structure is modeled, in order to further calculate the hydrostatic and hydrodynamic properties. The mesh of the structure is imported into a boundary element method code which provide option for hydrostatic computation, and solves the hydrostatic equilibrium for the given mass and center of gravity. Further, the hydrostatic data, mass distribution matrix, and hydrostatic restoring matrix is given as input for HAMS solver. ØyMerd is then modeled in the dynamic analysis software with the hydrodynamic data obtained from the potential theory software HAMS. The simulations in OrcaFlex contains a model of ØyMerd moored and service vessel, in order to analyze vessel operations in relation to the structure and wave parameters. Significant wave heigh and wave period data is analyzed for a potential production location. A weather window analysis is performed in order to identify the accessibility of the structure in relation to vessel operations. Vessel operations in relation to new types of offshore aquaculture facilities are facing new challenges which effects the safety and accessibility. It is important to avoid operations when the sea condition is close to either the aquaculture facility or the vessel natural frequency. Even though a structure like ØyMerd is stable in waves, sea conditions can lead to great response. For future work, wave disturbance and shielding effect benefits could be addressed.