Circular Aquaculture Fish Cage(Net Pen) Built

We design and supply Turnkey Solutions for marine and aquaculture industries.

Flexible plastic cages are made from high quality polyethylene HDPE 100 grade material, it's suitable for the dynamic load of the sea in the extreme conditions. Extensive use of strong and high-quality polyethylene material in cage brackets eliminates corrosion, minimizes expensive and difficult maintenance, and substantially increases the cage lifespan compared to steel brackets.

The 50m x 15m fish cage net pen for the system is a cylinder composed primarily of HDPE tubes, a steel mesh for netting and ropes to connect the various elements. Rib lines connect the float ring to the sink ring of the system. The bottom lines run from the front to the aft of the bottom ring and support the HDPE tube from deflecting in the current. Buoy Line connect the buoys to the float ring and support the net pen in its submerged configuration. Top Net Support Lines connect the Top Net Support pipe structure to the float ring. These lines transmit the force from the top net support and the nursery net, when in use, to the float rings. The top net support lines also run from the front of the cage to aft of the top net support structure to support the pipes from deflecting in the current, especially when the nursery net is in place. The nursery net is an additional containment net used during when fish are initially released into the offshore net pens from the hatchery. The fish, as fingerlings, are small enough to pass through the main containment net and escape. The solution to this is to use a secondary containment net with a much smaller mesh opening to contain the fingerlings until they grow to such a size that they can be released into the main containment net. The nursery net lines support the bottom of the nursery net, by connecting it to the sink ring. The top of the nursery net is supported by lashings to the top net support.

450mm Double Holes HDPE Bracket:

450mm HDPE PIPE, GRADE 100

Fish Cage Under Use:

DEFINITIONS OF THE MAIN CONSTRUCTION OF NET-PEN:

Component	Definition
Float Pipe, Inner	The float pipes provide the structural strength, circular profile and buoyancy to the netpen. The inner float ring is always buoyant and is foam filled.
Float Pipe, Middle	The middle float ring serves the same purposes as the inner float ring, but also acts as the variable buoyancy chamber for the ballast system. The ring has 2 chamber which means the ring is divided into two discrete sections each with an air vent and a H20 vent, separated by bulkheads.
Float Pipe, Outer	The outer float ring provides for similar functions as the inner float ring. The ring is generally flooded, but can be purged of water for additional buoyancy for surface operations.
Sink Pipe	Ring at bottom of cage. Composed of HDPE and filled with ballast for negative buoyancy. The negative buoyancy works with the float ring to provide tensile forces to the net and rib lines.
Bracket	Molded plastic that connects inner and outer float pipes. Equipped with sockets on dorsal surface over inner float pipe tunnel that anchors and supports stanchions. Generally held in place tangentially via welded stoppers. Brackets will be numbered clockwise, starting with forward most bracket and proceeding starboard.
Stanchion	Vertical pipe that supports handrail. It is supported by bracket.
Top Net Support	Sub-assembly of 2 rings and stanchions which functions to provide support for the top net and an air space below it when the cage is surfaced
TNS Top Ring	Structural Pipe that supports the Top Net out of the water at surface. Typically flooded, but not sealed
TNS Stanchion	Vertical Pipe that connects TNS Base Ring to TNS Top Ring. Typically flooded but not sealed
TNS Base	Structural Pipe providing buoyancy to lift top net out of water at surface. Typically purged.
Main Net	Vertical cylinder of mesh that makes up the majority of the net. Forms the “walls” of the pen
Top Net	Horizontal section of mesh, usually circular, at the top of the pen. Forms the “ceiling” of the pen.
Bottom Net	Horizontal section of mesh, usually circular, at bottom of the pen. Forms the “floor” of the pen.
Jump Net	Vertical cylinder of mesh that typically goes from float pipe to hand rail. Above water line while surfaced, traditionally to prevent fish jumping out in absence of a top net
Total Net	Summary net parameters, such as total volume, that are best expressed as cumulative from all net sections.
Nursery Net	Nylon net cylinder used inside of main net when fish are too small to be contained within the main net openings.
Rib Lines	Rib lines are vertical lines on the exterior of the net, supporting the sink pipe, usually suspended from one of the float pipes or brackets. Rib lines ensure that no weight is taken by the net itself.
TNS Lines	TNS Lines are used to keep the top net support in position.
Hand Rail Lashing	Lashings that connect mesh to the hand rail. Typically only support jump and top nets
Inner Float Pipe Lashing	Lashings that connect mesh to Inner float pipe. Typically support main net section.
Sink Pipe Lashing	Lashings that connect mesh to sink pipe. Typically support bottom net.
Buoy	Floating object that provides buoyancy. Should be have sufficient buoyancy to provide safety factor in pipe breach event.
Buoy Line	Rope connecting the buoys to the net pen. Typical knot - Boom hitch
TowLine Crowsfoot	Responsible for evenly distributing the mooring force into the cage structure. Number varies from 3-7, mirrored about the central bridal. In this structure, the tow line crowsfoot runs from the netpen to the barge riser.