VARD helps to pioneer innovative ‘Aqua Semi’ concept
The design reduces the risk of fish escaping and that of sea lice and other waterborne infections
The patented Aqua Semi solution features a partially enclosed, semi-submersible production unit inspired by semi-sub drilling rigs used in the offshore industry. The circular steel hull builds on the same principles, with the buoyancy ring pontoon located well below the water surface to ensure stability. Emptying or filling the pontoon raises or lowers the unit as required.
Designed to withstand higher wave heights, Aqua Semi will be secured in position by anchored double chains and is intended specifically for deployment in rougher waters with strong currents, allowing the use of so far unutilized areas for fish farming. The platform’s steel walls will be solid to a depth of 17 metres, with all operational functionality fully integrated into the structure and giving a total interior tank volume of around 75,000 m3, with a diameter of 67.5 metres and capacity for more than 600,000 fish. Adjustable openings in the hull will allow continuous throughput of fresh and oxygen-rich water, using pumps at times of weaker current and additional oxygen on demand. The base and openings will be covered with a grid of rust-free steel netting.
During the design and verification phase a lot of effort, including fluid dynamics analyses and extensive model testing, has gone into developing a fish farming unit that is fit for purpose with equipment integrated to withstand the harsh conditions and ensure fish welfare.
Comprehensive studies have also been conducted to identify the biological parameters for water quality in a semi-closed unit containing a large amount of biomass.
The design reduces the risk of fish escaping and that of sea lice and other waterborne infections through shielding the fish from the upper water mass and a shorter production cycle of 10 to 11 months. Efficient handling of harvest-ready fish as well as control and management of the growing environment, including light and underwater feeding, will contribute to improved biological performance and growth. VARD is now verifying the design through detailed engineering in order to quality assure the technical solutions.
Senior Naval Architect Thomas Olsvik in VARD’s Conceptual Design division said:
“Being involved in this project means a lot to our team at VARD. Aquaculture is fast-growing industry and a key contributor to a sustainable Blue Ocean economy today and in the future. It’s exciting to use our combined multidisciplinary knowledge to adapt and evolve technology that pushes the boundary of what’s possible. An important aspect is working with collaborators and finding the best possible solutions in concert with them. We believe we have the capacity and experience to bring the Aqua Semi concept into reality.”