A large tension anchored cage provides high robustness, stability, escape security and good fish welfare - suitable for use in offshore weather and adapted to local conditions.
a) Floaters are located below sea level.
b) Tension anchoring includes anchor buoys with hook on, vertical anchor.
c) Anchors designed to sea bottom condition.
The cage should be robust and able to resist extreme weather. The use of a concrete 8-edge collar with wind and wave breaker leads to desired stability and lower construction and maintenance costs. Simple hook on provides lower installation costs. The lower beam has grab arms linking to the anchor lines and to stretch out the net vertically and horizontally.
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Most important is the net section (lower beam with grab arms). It includes two large and hollow 8-edged beams and a wire net. The net section will be added or removed from the cage structure in offshore location as needed. The upper beam is attached to the concrete collar (special plug in to ensure it is tight). The diameter of the upper beam is slightly larger than the diameter of the lower beam - because both should be in surface position when mounting the wire-net, at an onshore location. After net section assembling, it will be towed to localization for cage mounting. The net section is inserted between the anchor lines in vertical position, then twisted to horizontal position.
Another important element is the hook on concept using ballasting during hook on and tension anchor the collar. Tension anchoring means less sea area tie up – better for synergies with other installments and less costly sea activities during link up. The anchor system includes a lower collar bin with anchor and anchor lines and the hook up element on top of the anchor line.
Further unique elements - the 8 edged collar - has a total height of 18 m and a diameter of 125 m. The lower part will be in operating position 11 meters below the surface of the water. The depth of the collar protects the net and represents in itself risk reduction. In the lower part of the collar are 16 two levels (2 x hollow torus) that extends around the entire collar. The 2 x torus has a height of nearly 6 m and diameter of 3.1 m. By deballasting – pumping out water - the collar will get increased uplift – which is needed to achieve tension anchoring of the collar. The concrete wall – having openings – will absorb wave and wind energy. Further reviews are needed to determine optimal opening and form on the wave breaker. Concrete 8 collar elements are bound together by a special link - it possible to build two and two items together and then link them together. The collar elements can be build at a ship yard or a special jetty in Norway. Concreate means d link all the elements together.
lower capex compared to a steel collar.
The wind power can be designed to supply power use in fish farming or a lager production if export cable available. Alternative 1 is a vertical wind turbine with flip in blades – to avoid turbine damage during extreme weather. A large battery is included. Alternative 2 is a wind kite linked to the collar. Largest power consumer is fish feeding. e fish eats when it is hungry (day light). Big fish eats more than small - estimated a need of 25-45 kW when fish eat - daily average consumption estimated to about 10-15 kW
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