Hydrodynamic analysis of huge-framed offshore aquaculture platforms and design of their mooring systems

As offshore aquaculture platforms typical of huge-framed structures which support the net are being deployed further offshore, the hydrodynamic performance of the platforms is quite complex and yet very important to the adequate design of the platforms and their mooring systems as any significant underdesign or overdesign of the platforms and mooring systems can incur serious economic consequences. A method based on Morison equation was proposed for the assessment of the hydrodynamic loads on the aquaculture platforms including their frames and nets. A Morison model for an aquaculture platform was constructed, which could take into account the sheltering effect due to the surrounding net or beams through the equivalent hydrodynamic coefficients in three directions. The numerical analysis results of free attenuation show that the natural periods of heave, pitch and roll are far greater than those of conventional floating structures. A mooring system combining polyester with chains was designed to endow the whole system with less rigidity in transverse direction, followed by the time domain analysis to assess the hydrodynamic forces and mooring system performance in various environmental conditions. The numerical results indicate that the mooring tension can meet the design requirements, the safety factor of cable in good condition is 2.07, and the safety factor with one line broken is 1.463. © 2023 China Ship Scientific Research Center. All rights reserved.