“These concepts will also be interesting in other parts of the world where farming is taking place - Chile, Scotland, Alaska, Canada, China… It is a good opportunity for other countries to have fish farms further offshore, away from the coast. In Norway this started as a small market but in 10 years it is a global product. We are taking the lead like we did in the oil and gas market.”
Odd: “Who knows where we will be in 20 years’ time? Two young teachers started Nova Sea in 1972 in North Norway when everybody was saying it wasn’t possible to farm fish that far north. It was too cold, too dark. They flew 1200 young fish in plastic bags over to the island of Lovund in a seaplane and only 174 survived to full maturity. Many people said this was proof it
would be a disaster, but our founder thought this was actually a success and the start of something. We now produce 50,000 tonnes a year today and we handle some 12.5 million smolts per annum. The feeding barge supplies 400 tonnes of feed. So, if this is in 40 years, imagine what we will see in the next 20 with developments like these!”
Two concepts based on semisubmersible technology
Viewpoint Seafarm and the Spider Cage concepts are both innovative, offshore fish farm solutions based on semisubmersible technology. Viewpoint Seafarm comprises a hub, which is (semi) supporting four floating net cages interconnected through a dedicated hinge system. Each floater has a projected area (seen from above) of approximately 50 m x 35 m. In the tests it has been demonstrated that the cages provide the required stability to survive conditions up to Hs 11 m.
The Spider Cage is a completely different concept designed to keep sea lice out of the farm. A dedicated barrier, with a
diameter of approximately 100 m, has been constructed shielding the actual fish cage from heavy sea conditions and lice. Tests have been performed up to sea states of 11 m with and without current, where general motions, accelerations, loads and sloshing have been assessed.
In order to simulate the behaviour of the concepts accurately it is important to truly understand the scaling laws for the net structures in relation to waves and current. An important factor is to be aware of the flow within the fish cage to assure high standards for the welfare of the fish. Hence the flow measured at scale should
accurately represent the flow at full scale. In close cooperation with ICON SYSTEMS and Viewpoint Seafarm, we have performed dedicated tests to assure that scaling related to the net structure and the flow in/around the structure are representative and well understood. Both concepts have been tested successfully and the findings of the test campaign have been recorded for the successful continuation of the development of the fish farm designs.
Rene Lindeboom
r.lindeboom@
marin.nl
report
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