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Why do Farmocean cages often ride through a storm while other cages don't?

One of the reasons is the construction principle of the cage. It works the same way as the semisubmersible oil platforms on the North sea.

The "secret" is that the floating capacity isn't concentrated to the sea surface as for most cages but three meters below the surface where the wave moment is only a fraction of that at the surface.

Just as the oil platforms the Farmocean cages are designed to cater for severe storms.

How does an offshore cage work?

The Farmocean offshore cages encloses some 6000, 4500 or 3500 cbm of water depending on the net design. The cage itself consists of a tubular galvanised steel structure mounted on a hexagonal pontoon incorporating six ballast tanks. In its normal operating mode, the farm floats in a semi-submerged position with the pontoons three meters below the water surface. The upper platform and the feed silo are in this position located three meters above the surface.

The design is made to withstand offshore conditions and it has been approved and verified by Veritas of Norway. The net is kept in place even in strong current by a sinker tube outside the bottom of the cage. Due to its submerged pontoons the cage stay calm in heavy sea decreasing the risk of losses of fish or damages to the cage. The system has been exposed to more than 10 meter waves without any damages to the cage.

TThe Farmocean cage is equipped with a computer controlled feeding system permitting feeding of the fishes continuously during preselected periods of the day. This give as a result a better growth and a reduced feed conversion factor . The fish will also be fed during days when the farmworkers stay ashore due to bad sea conditions. Feeding is also continuously matched to water temperature, wave conditions and biomass growth.

All normal work is carried out from the upper platform around the feed silo. Normally this means that one person board the cage for the daily collection of data from the computer regarding feed, wind, waves and temperature. For inspection, treatment, harvest, etc. the farm can quickly be deballasted to surface position. A gangway running around the pontoons provides a safe platform.