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Christopher Bull

Aspiring oceanographer. PhD candidate (UNSW). Big data python enthusiast. Outdoor adventurer.

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Today is an exciting day, we’ve just started retrieving our first mooring. I wanted to take this opportunity to explain what a mooring actually is. For our experiment we have deployed five moorings to monitor the East Australia Current, our mooring array looks like… 

[caption id=”attachment_430” align=”aligncenter” width=”300”]image: Danny McLaughlan image: Danny McLaughlan[/caption]

What does each item record? How much do they cost?

Starmon mini

Records: temperature and no pressure

Sample time: five minutes

Response time: 30 seconds

Accuracy: 50/1000 degree

Cost: $800

[caption id=”attachment_429” align=”aligncenter” width=”300”]Starmon's record temperature. Starmon’s record temperature.[/caption]

Seabird SBE37SMP

Records: pressure, temperature and conductivity.

Sample time: ten minutes

Response time: milliseconds

Accuracy: 1/1000 degree

Cost: $8,000

[caption id=”attachment_434” align=”aligncenter” width=”300”]Seabird's record pressure, temperature and conductivity. Seabird’s record pressure, temperature and conductivity.[/caption]

Aquadopp

Records: single point current, temperature, pressure and depth

Sample time and output: every 30 seconds to output an average every 30 minutes

Accuracy: 100/1000 degree

Cost: $16,000

[caption id=”attachment_427” align=”aligncenter” width=”200”]Aquadopp's record single point current, temperature, pressure and depth. Aquadopp’s record single point current, temperature, pressure and depth.[/caption]

Acoustic Doppler Current Profiler (ADCP)

Records: velocity profile and pressure

3 different sorts:

  1. WH300 and BB150
  • Range: 300/150 metres (respectively). Price: $40,000-50,000
  1. LR 75
  • Range: 600 metres. Price: $80,000.

Sample time and output: every 15 minutes to output average hourly

[caption id=”attachment_433” align=”aligncenter” width=”300”]Acoustic Doppler Current Profilers records water velocity and pressure. Acoustic Doppler Current Profilers records water velocity and pressure.[/caption]

**Acoustic release (two on every mooring for redundancy) **

Function: when release signal is detected, anchor is detached from mooring so that the buoyancy on the mooring makes the mooring float to the surface.

Cost: $18,000

[caption id=”attachment_432” align=”aligncenter” width=”300”]Acoustic release. Acoustic release.[/caption]

Buoyancy

Benthos glass floats ($600-800 each) and syntactic spheres ($12,000-$18,000). We can see what a syntactic spheres looks like in the ADCP picture above. The wire costs $3.15 a metre and the Dynex $3.45 a metre.

[caption id=”attachment_431” align=”aligncenter” width=”300”]Benthos glass floats (buoyancy) Benthos glass floats (buoyancy)[/caption]

Exeos equipment

Function: help locate the mooring when the top is at the surface.

Instruments are: led flasher, vhf beacon and sable (gps) – $1500, $1500 and $8000 respectively.

[caption id=”attachment_428” align=”aligncenter” width=”300”]Exeos led flasher, vhf beacon and sable. Exeos led flasher, vhf beacon and sable.[/caption]

Check out our interview with moorings engineer Andreas Marouchos, we have a chat about the technical challenges with designing and deploying moorings.

In category: Southern_Surveyor