The technology used in OCEANIS 2 submersible cage best combines the typical features of a floating cages, such as the easy access and management during the day by day farming activities, with the safety in terms of resistance to force of the wave-motion allowed by a totally submersed position.
OCEANIS 2 has been developed with the experience of over 10 years with offshore fish farming.
The OCEANIS 2 submersible cage is characterized by the following features:
- Buoyancy pipes constantly filled with air, and then always positive;
- A compensation chamber (alternately floodable by water or filled by air) is located under the cage net and over a series of appropriate weights (ballast), generally made of chains, with a total weight greater than the buoyancy of the upper pipes.
The change in the cage attitude (floating or underwater) is achieved by alternately filling and emptying the compensation chamber. So, in the OCEANIS 2 management we can identify the following cases:
- Compensation chamber filled with air: the cage is in flotation as the overall buoyancy of the HDPE pipes (the compensation chamber) exceeds the weight of the chains;
- Compensation chamber flooded: the cage sinks and the down part of the chain positioned below the chamber, starts to lean and fold on the sea bottom, until the upper part, which is still hanging and weighting below the cage (and still not laid down on the bottom), equals the buoyancy of the pipes. In this condition we have a stable equilibrium.
The theoretical sinking bathymetry of this cage can be defined by calculating the vertical distribution of weights placed under the cage. Furthermore, the depth level is also related to the depth of the grid system.
The maximum sinking depth of the cage is generally twice the depth of the grid system. In this case, the compensation chamber is similar to a “diving bell”, carried out with a hot-dipped steel cylinder closed at the top only. The total volume of the diving bell and the upper HDPE pipes must ensure an equal buoyancy to lift enough length of the chains used as ballast, to make the cage float. The bell is located below the sinker tube using chains or ropes. Weights are installed under the bell.
The mooring system is the same used in floating cages: a grid mooring system. The reticular system is one of the best cost-effective ratio mooring layouts among all those used within the cage farming market.
- Oceanis 2 requires a traditional single buoy mooring line.
There is no need for hanging support to the mooring grid due to the equal buoyancy/ballast system design.
- Minimum Depth: 50 mt
- Maximum Net Depth: 12 mt
- Minimum Cage Diameter: 16 mt
- Maximum Cage Diameter: 30 mt