A Prototype Tool for Analysis and Design of Floating Fish Cages

Floating fish cages are the main means of production in the multi billion euro salmon farming industry. Despite its pivotal role in production safety, protection of values, as well as in protection of the environment, neither verified structural design procedures nor computer tools for structural analysis and design have received much attention. To a large extent they can be regarded as not being in accordance with the current state-of-the-art of structural analysis and design of slender marine structures. A momentum to move towards a more scientific based design approach has been created by the requirements of the recently introduced Norwegian certification criteria and the accompanying design code NS 9415. A prototype for analysis and design of floating fish cages has been developed and is described herein. The tool is based on an object-oriented framework for general FE analysis. The framework has among other things been developed with ease of extensibility for the software developer in mind. The prototype is thus intended for iterative extension of the functionality. In the first development iteration, described here, the FE framework has been extended, with hydrodynamic load models and a user interface for analysis of floating fish farms. The development of the prototype shows that by building on an object oriented FE framework, specialized and focused applications for aquaculture can be developed with limited effort. As an example analysis — and a possible benchmark — a simplistic model of a steel frame is chosen. Comparison of results obtained with different load formulations indicated that the buoyancy load was more important than the hydrodynamic load.