PRIMaRE Annual Conference                                                    Wednesday 6th April 2011              In this...
PRIMaRE Annual Conference                                                     Wednesday 6th April 2011              Moorin...
PRIMaRE Annual Conference                                                          Wednesday 6th April 2011              T...
PRIMaRE Annual Conference                                                        Wednesday 6th April 2011              Sil...
PRIMaRE Annual Conference                                                    Wednesday 6th April 2011              We desi...
PRIMaRE Annual Conference                                                Wednesday 6th April 2011              Images of t...
PRIMaRE Annual Conference                 Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk)                 ...
PRIMaRE Annual Conference                                                      Wednesday 6th April 2011              The p...
PRIMaRE Annual Conference                                                    Wednesday 6th April 2011              This PO...
PRIMaRE Annual Conference                 Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk)                 ...
PRIMaRE Annual Conference                 Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk)                 ...
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Jim Elliot Presentation

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Developing low cost, light weight POD moorings for tidal-stream habitats by Jim Elliot and Ben Wilson

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Jim Elliot Presentation

  1. 1. PRIMaRE Annual Conference Wednesday 6th April 2011 In this study, we explored the options of deploying devices designed to log odontocete echolocation clicks (C-PODs) in a prospective tidal-stream energy site off the west of Scotland. Our design needed to be deployable from a chartered research yacht; the gear be light enough to be manually handled by two people with a small capstan and that the mooring maintain the submerged POD orientated vertically even in tidal streams.by Jim Elliott (jim.elliott@sams.ac.uk) 1
  2. 2. PRIMaRE Annual Conference Wednesday 6th April 2011 Mooring scientific recording equipment in marine habitats is ordinarily challenging. But securing recorders in sites suitable for the extraction of marine renewable energy is more so because a) The inherent energy of the site substantially increases the risk of the equipment being moved or broken b) The incumbent water motion makes it particularly hard to maintain correct equipment orientation and c) fouling, sand blasting and scour are particularly prevalent . The specific difficulties differ between wave and tidal-stream energy sites but the lack of experience in these sites and associated absence of fully tested “best practise” is common to both.by Jim Elliott (jim.elliott@sams.ac.uk) 2
  3. 3. PRIMaRE Annual Conference Wednesday 6th April 2011 The channel at the centre top of the image is Kyle Rhea between Skye (left) and Glenelg (right) POD #664 was moored in a sheltered eddy with the greatest effect of tidal flow. POD #667 was moored in a couple of locations in a secondary context. POD #666 was further to the south and thus less likely to experience the tide.by Jim Elliott (jim.elliott@sams.ac.uk) 3
  4. 4. PRIMaRE Annual Conference Wednesday 6th April 2011 Silurian is run by the Hebridean Whale and Dolphin Trust and is used for marine wildlife research and volunteer trips.by Jim Elliott (jim.elliott@sams.ac.uk) 4
  5. 5. PRIMaRE Annual Conference Wednesday 6th April 2011 We designed two moorings based on the popular ‘J’ design. The difficulty of tidal effect on buoyed lines from bottom to surface meant an individual weight system for the C-PODs was required. C-PODs have 0.7kgs of inherent buoyancy so a riser line (3 m of 10 mm Seasteel) was weighed by 25 kg of 6 mm long link chain and buoyed by a solid 5 kg float. A ground line (16 mm Seasteel) equal to the depth connected this to the main weight (concrete and chain filled tyre weighing 50 kg). This was then attached to the surface (via 12 mm Seasteel) by a polyform ‘40’ inflated buoy and two metre pickup buoy. Key to the deployment was the positioning of the equipment relative to the tidal-stream. C-PODs have a detection range of approximately 200 metres for porpoise. With the mouth of the site (Kyle Rhea) being less than 150 m wide, the topography of the shore favoured a relatively sheltered location close to the southern channel. As a comparison, a second mooring was laid 15 km to the SSE in a low energy site.by Jim Elliott (jim.elliott@sams.ac.uk) 5
  6. 6. PRIMaRE Annual Conference Wednesday 6th April 2011 Images of the deck, POD, main weights and surface buoys.by Jim Elliott (jim.elliott@sams.ac.uk) 6
  7. 7. PRIMaRE Annual Conference Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk) 7
  8. 8. PRIMaRE Annual Conference Wednesday 6th April 2011 The peaks show the influence from the tide as the POD is knocked down.by Jim Elliott (jim.elliott@sams.ac.uk) 8
  9. 9. PRIMaRE Annual Conference Wednesday 6th April 2011 This POD was moved from various areas which show a change in influence by the tide.by Jim Elliott (jim.elliott@sams.ac.uk) 9
  10. 10. PRIMaRE Annual Conference Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk) 10
  11. 11. PRIMaRE Annual Conference Wednesday 6th April 2011by Jim Elliott (jim.elliott@sams.ac.uk) 11

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