NEW BIRD NET DESIGN FOR OFFSHORE CAGE FARMING

Transcription

1 NEW BIRD NET DESIGN FOR OFFSHORE CAGE FARMING Experimental Study under influence of waves Presented by : ALESSANDRO CIATTAGLIA Sales & Marketing Manager BADINOTTI GROUP Spa

2 TABLE OF CONTENT Experimental Study Presentation Introduction Experimental Setup Methodology Measurement & Analysis Results

3 About Us

4 ABOUT US Serving your Fishery and Fish Farming Businesses since BADINOTTI GROUP provides: Cage Aquaculture Turnkey Project Feasibility Study for Fish Farming Business Cage Nets, Anti-Predator Nets Cage Mooring Design and Calculation Aquaculture Equipment Net Services, Treatments and Maintenance Nets for Commercial Fishing PVC Floats, Twine and Ropes HDPE Boats

5 WHERE WE ARE Worldwide Factories and Branches Badinotti Marine Equipment Italy HDPE Boats P Badinotti Group - Italy Head Office H 05 Badinotti Slovakia Fish Farming Nets Fishing Nets Sport and Safety Nets P Badinotti Peru Fishing Nets P Badinotti Chile Fish Farming Nets P P = Production SV = Services SA = Sales Office Badinotti Net Services Chile Fish Farming Net Service Badinotti Marine Equipment Chile Mooring Design and Installation Cage and Boat Tugging SV SV Badinotti North America Fish Farming Nets Fishing Nets Sport and Safety Nets Badinotti Net Services Canada Fish Farming Net Services SA SV

6 BADINOTTI GROUP TURNOVER Year 2014 USD K K North America K Europe, Africa & Middle East South America Aquaculture Fishing Services

7 BADINOTTI GROUP HUMAN RESOURCE Year Canada 100 Europe 350 Peru 400 Chile

8 INTRODUCTION Problem Solving: Bird Net Protection in High Energy Site 08 Problem Focus : Solution Focus : Net has stressing and stretching movements and consequently rips off Improving netting strength generates breaks on the handrail pipes Netting falls into the water and consequently the fouling grows UV radiation influence Netting panels cut and assembled in diamond mesh shape More elastic behaviour generates a lighter netting requirement No cross top ropes are needed so less breaks risk on the handrail A lighter netting requires a simpler support Special Resin Treatment Problem Problem Clarification Idea Generation Idea Selection Test Results

9 Experimental Setup

10 EXPERIMENTAL SETUP The Flume Tank 10 Technical information: Dimensions Overall: L:30m x H:6m x W:8m Measuring section: L:21.3m x H:2.7m x W:8m. Volume of water: 1200 m3. Windows: W20m x Η3m Propulsion Four propellers driven by AC motors of 55 KW generate the flow. The maximum speed of water thorough the test section is 1 m/s. The bottom of the test section is covered by a conveyer belt type made of nylon. The speed of the conveyer belt is adjustable and can be locked with speed of the water or can be driven at a set speed.

11 EXPERIMENTAL SETUP Experiment performed in a model scale 1:25 11 Wave Generator The waves used for the experiment had a significant height of 5.5 m and a period of 7 seconds. HD Video Cameras High definition surveillance cameras were positioned at different viewpoints Flume Tank The sketch above shows how the net cage system is set up in the flume tank. The distance between the mooring points is 7,5 m corresponding to 188 m in full scale this implies that only a part of the mooring lines are modelled in the flume tank. It is however assumed that this will only have minor influence of the performance of the floating rings. Floating Rings A flexible floating ring with a diameter of 2 meters (scale 50mt) was used to support the bird net. The buoyancy of the ring was obtained using a cylinder of waterproof rubber foam tread on a thin steel rod. The floating ring was moored using a multi legged connection in each corner of a surrounding square rope frame. This frame was supported by mooring lines attached to the walls of the flume tank.

12 EXPERIMENTAL SETUP Experiment performed in a model scale 1:25 12 Bird Nets Two Nylon nets were tested. A traditional design with essential square meshes and a new design with diamond meshes all along the floating ring. Strain Gauges Two strain gauges were mounted on the bird net, one in the front of the net and one in the back. The strain gauge was secured to the handrail of the floating ring and the other end to the netting Hamster Wheel A hamster wheel with a diameter of 60 cm (scale 13mt) was used. It was secured in the middle of the floating ring with four lines Motion Tracking The bird net was equipped with 16 reflectors. Eight reflectors on the edge of the bird net towards the floating ring. Five reflectors on the net, positioned over the Hamster Wheel. Three reflectors between the floating ring and the hamster wheel on the bird net closest to the incoming waves.

13 Methodology

14 METHODOLOGY 14 Initiate the Wave Wait a minute for the wave to stabilize Log a simultaneous time series of the motion of the 16 reflectors. The length of the time series is 100 seconds (model scale values). This will correspond to a 500 sec. period in full scale. Make a video footage of the behavior of the system consisting of the floating ring and the Bird net.

15 Analysis

16 BIRD NETS LAYOUT COMPARISON Video Camera Recording 16 VS Traditional Bird Net Design New Bird Net Design

17 BIRD NETS LAYOUT COMPARISON Diameter of the Flexible Floating Rings 17 VS +/- 1 mt Diameter Variation +/- 4mt 46,9mt 50,5mt Perpendicular Wave 44,1mt 52,2mt 47,2mt 50,2mt In Wave Direction 46,6mt 54,1mt

18 BIRD NETS LAYOUT COMPARISON Tension on the Flexible Floating Rings 18 VS -706 kg -151kg Average Tension 85 kg -471kg kg 1688 kg In Front -921 kg 307 kg -614 kg 768 kg In Aft -614 kg 1075 kg

19 Results

20 RESULTS Bird Nets Comparison Test 20 The diameters measured MIN 47m and MAX 56 m. However, the range (min to max) is 3 meters for the traditional design, while the range is about 8 meters for the new design. The deformation of the floating ring can be more than doubled when a bird net of the new design is attached to the ring compared to the bird net of the traditional design; this is mainly due to the difference in the shape of the meshes in the two design. The Tension Forces caused by the front waves is decreased on average by a 1/3 from -707 kg to -471 kg with the new design.

21 WHAT THE RESULTS MEAN Advantages in the new design 21 Due to the higher capacity to withstand tension forces (approx 3 times more), it could be possible to use light netting Strength Weight Using a lighter birdnet means saving buoyancy on the birdnet support and keeping the netting always above the waterline level easier. Price Lighter netting in bird net assembling means cheaper price. Furthermore the new design uses same work time and material of the traditional design.

22 THANK YOU VERY MUCH For Your Kind Attention BADINOTTI GROUP spa Viale Ortles, MILANO - ITALY +Tel Mob alessandro.ciattaglia@badinotti.com