towed undulating oceanographic vehicles from chelsea technologies group
TRANSCRIPT
www.chelsea.co.uk
Introduction
Application of sensor technology
Process control & monitoring
Medical diagnostics
Algal biofuel production
Fresh water & coastal monitoring
Offshore pipeline leak detection
Hydrocarbon pollution monitoring
NAD
Tactical Oceanography
Acoustic Target Simulation
Oceanographic research
Sensors & systems
Acoustic transducers
Fisheries
Exhaust gas monitoring
Ballast water monitoring
FerryBox
Security
Water Quality/Treatment
Bio/chem Security
Storage Tank Security Environmental
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Introduction• Overview of CTG Towed Vehicle Systems• Description and Deployment of vehicles
– SeaSoar– Nν-Shuttle– AquaShuttle III
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Why tow vehicles?
•Traditionally a profile of the upper ocean is taken by using profiling CTDs
– Requires vessels to stop at set stations
– Number of achievable casts are limited per mission
– Disturbs other operations required from vessel
– Multiple deployments per mission = multiple risks
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Advantages
• Provides profiles to significant depths with towing vessel underway
• Just deploy and recover at start and end of transect or journey
• No cable reeling on deck once deployed
• Provision of real time data can provide immediate points of interest to further investigate
• CTG platforms offer a large and flexible cargo area for instruments
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Towed Vehicle Selection•Criteria
• Depth requirement
• Parameters required (Payload implications)
• Tow speeds available from host vessel
• Size of host vessel
• Budget
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Towed Vehicle Comparison
AQUAshuttle III
Nν-Shuttle SeaSoar
Tow Speed Range (knots)
8 to 25
5 to 15
6.5 to 12
Undulation range unfaired cable
0 to 65m
0 to 80m
0 to 100m
Undulation range faired cable
0 to >125m
0 to >160m
0 to >500m
Payload 20 litres 60 litres 85 litres
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Winch Selection•Is there a winch already available?
•Depth and Speed requirement – Defines Light or Heavy Duty Winch
•Hydraulic or Electric?
•Size of host vessel
•SeaSoar requires winch for faired cable
•See CTG website for winch specifications
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Cable Requirements
•Cable type used for towed vehicle dominates performance achieved
•Large diameter = Large drag = shallow depth performance
•SeaSoar demands conductive cable for operation
•Nν-Shuttle and AquaShuttle benefit from use of conductive cable
•CTG has identified the Rochester 7-314-AXX as the ‘ideal’ commercially available cable
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Cable Specification•Type
•Diameter
•Conductors
•Breaking Strain
•Working Load
•Bend Diameter (min)
•Weight in Air
•Weight in Fresh Water
Rochester 7-H-314AXX
8.2mm
7 + Armour
51.6kN
20.0kN
43cm
268 kg/km
220 kg/km
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Cable Fairing•Reduces drag on the cable as it passes through the water
•Advantages
• SeaSoar Depth Range increases from surface to 120m to surface to 500m
• Nν-Shuttle Depth Range increases from surface to 80 metres to surface to 150m
•Disadvantages
• Additional Cost
• Requires purpose built winch of large drum diameter
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Fairing Specification•Type
•Weight in Air
•Thickness
•Chord
•Length
•Nose Hole
•Minimum Bend Diameter
•Max Cable Diameter
Indal Flexnose Style FA-478-350-1
0.28 lb/ft
0.48”
1.92”
4”
0.35” dia
36”
0.333”
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Towing Sheaves
•2 towing sheave designs available from CTG
• Towing Sheave for Faired Cable
• Towing Sheave for Non-faired Cable
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MiniPack CTD-F Features•Mechanical
•Size
•Weight in Air
•Pressure Rating
•Communications
•Input
•Tx
•Scan Rate
•Integral Sensors
114mm dia x 200mm
6kg
600m (Titanium / Acetal)
16 analog external channels
RS232 or RS422
1 Hz all channels
CTD Fluorescence
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MiniPack II Specification
Type Range Accuracy Resolution
Conductivity Inductive Cell 0 to 70 mmhos/cm
0.005 mmhos/cm
0.001 mmhos/cm
Temperature Pt Resistance -2 to +35 C 0.003 C 0.0005 C
Pressure Strain Gauge with temp compensation
0 to 600 dbar 0.2 dbar 0.01 dbar
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MiniPack Fluorometer SpecificationFluorimeter Excitation
(nm)Emission(nm)
Concentration(ug/l)
Resolution(ug/l)
Chlorophyll-a 470/30430/30
685/30685/30
0.03 to 1000.03 to 100
0.01
Rhodamine 470/30 590/45 0.03 to 100 0.01
Amido Rhodamine
425/30 550/30 0.04 to 200 0.025
Fluoroscein 480/80 530/30 0.03 to 100 0.01
Nephelometer 470/30 470/30 0.04 to 100 0.01 FTU
Phycoerythrin 530/30 580/30 0.03 to 100 0.01
Phycocyanin 590/35 645/35 0.03 to 100 0.01
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SeaSoar Specification
•Length (excluding Bridle)
•Height (rudder bar down)
•Width (over wing hooks)
•Weight in air
•Max Depth
•Max tow speed
•Min tow speed
•Cable Requirements
1.5m
0.98m
1.6m
150kg
500m (with fairing)
10 knots (with fairing)
5 knots (with fairing)
1000m, 750 m faired
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SeaSoar Deck System
•Combination of SeaSoar Controller and CTD station
•CTD Station either MiniPack CTD-F or Seabird 911
•SeaSoar Controller runs CFlightWin
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SeaSoar Alternative ConfigurationsDATA
ACQUISITIONPC
DECK UNIT
FLIGHTCONTROL
PC
SEASOARDECK UNIT
SERVO VALVE
HYDRAULICRAM
WINGS
PRESSURESENSOR
C.T.D. SENSOR
IMPELLER
FEEDBACK SIGNAL
CONTROL SIGNAL
DECK UNIT
UNDERWATER UNIT
DATAACQUISITION
PC
DECK UNIT
FLIGHTCONTROL
PC
SEASOARDECK UNIT
SERVO VALVE
HYDRAULICRAM
WINGS
C.T.D. SENSOR
IMPELLER
DEPTH SIGNAL
CONTROL SIGNAL
DECK UNIT
UNDERWATER UNIT
FEEDBACK LOOP
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SeaSoar Deployment•If deploying new cable, ensure this is de-torqued prior to deployment
•Conduct pre-launch checks using Wing Control Box
•Set SeaSoar to a level tow depth of 20 – 30 metres
•Check water depth
•Operators: 2 at winch, 2 at vehicle, 1 at A frame, 1 at control
•SeaSoar centred at A frame, nose towards stern
•Always maintain tension on cable
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SeaSoar Deployment (Continued)
•Vessel speed to be 4 knots during deployment
•Once in water veer cable at 0.5 metre / second
•At 50 metres, increase vessel speed to 6 knots
•Increase veer speed to 1 metre / second (no faster) beyond 100 metres
•Increase speed to 7 knots once fully deployed
•To obtain maximum performance, 750 metres cable out, 8.0 – 8.5 knots
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CFlightWin Features•Logging of SeaSoar flight data to PC
•Control of the SeaSoar within CONFIG menu
•Selection and Set-up of Pressure Data input
•Control Parameters
•gain0 – shallow region Gain value
•gain1 – deep region Gain value
•pres0 – transition region centre
•deltaP – depth interval of transition
•Setup of Sawtooth; min depth, max. depth, period & period up
•Plot Variables
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NuShuttle Specification•Length (excluding Bridle)
•Height (rudder bar down)
•Width (excluding sponsons)
•Weight in air
•Max Depth (with fairing)
•Max Depth (without fairing)
•Max tow speed (without fairing)
•Min tow speed
•Cable Requirements (faired)
•Cable requirements (non-faired)
1.3m
0.57m
0.5m
72kg
150m
80m
15 knots
5 knots
350m, 150 m faired
500 metres
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NuShuttle Deck System•Single Rack Mounted PC Station
•Marine Interface Unit
•Runs MiniPack GUI
•Option for GPS input
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NuShuttle Deployment•Conduct pre-launch checks checking communications with the MiniPack and the Servo Unit
•Set to 3 metres level flight
•Check water depth
•Operators: 1 at winch, 1 at vehicle, 1 at A frame
•Always maintain tension on cable
•Vessel speed to be 4 knots during deployment
•Once in water veer cable at 0.5 metre / second
•Start tow vessel acceleration to 8 knots
•If operating without slip rings, check communications at 50 metre cable out point
•To obtain maximum performance, 275 metres cable out, 9 knots
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NuShuttle Performance
0
200
400
600
800
1000
1200
1400
14:0
0:00
14:0
0:56
14:0
1:52
14:0
2:48
14:0
3:44
14:0
4:40
14:0
5:36
14:0
6:32
14:0
7:28
14:0
8:24
14:0
9:20
14:1
0:16
14:1
1:12
14:1
2:08
14:1
3:04
14:1
4:00
14:1
4:56
14:1
5:52
14:1
6:50
14:1
7:50
14:1
8:49
14:1
9:45
14:2
0:41
-40
-20
0
20
40
60
80
100
SPEED rpm
CABLE OUT Metres (in w ater)
ACTUAL DEPTH Metres
CMND DEPTH Metres
WING ANGLE Degrees
SHIPS SPEED knots
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TPlot8 Features
•Display of real time Data in tabular form
•Display of Data in Graphical form
•Playback of Data or Log File
•Setup of Nν-Shuttle Min & Max Depth, Climb Rate
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Servo Parameters•Main Parameters set from MiniPack GUI
•Maximum Depth (metres)
•Minimum Depth (metres)
•Climb Rate (metres / minute)
•Bottom Avoidance Setting (metres above bottom)
•PID Settings - Set within Shuttle Terminal View
•Change Proportional (P) and Integral (I) terms only when tuning required
•$ command to view settings
•KI then P or I to change variable followed by value <CR>
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Servo Settings TableSystem
Description Required
PerformanceSettings
Upper Depth
Lower Depth m
Upper Depthm
Lower Depthm
Climb Ratem / min
Cable Scopem
Tow Speedknots
P I D
Shallow Tow Near surface
5 -1 6 5 13 8 0.3 0.009 0
Shallow Tow Near surface
10 -2 13 10 16 8 0.3 0.009 0
Shallow Tow Near Surface
20 -6 24 10 28 8 0.3 0.009 0
Deep Tow Near Surface
80 -10 80 55 180-270
9 0.3 0.03 0
Deep Tow – Faired Cable
Near surface
150 -15 165 57 315 10-11 0.1 0.01 0
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Mariner NuShuttleStandardised Instrumentation Package
for Large Marine Ecosystem (LME)
programme.
Instrumentation Package includes:
•MiniPack CTD-F
•Autonomous Plankton Sampler
•Fastracka II
•Optical Plankton Sampler
•Dissolved Oxygen
•Nutrients