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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Description of AHAB design Physical Structure
Mooring Buoy and Tether System
Mark Yarbrough Moss Landing Marine Laboratories
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
MOBY Calibration Site- Lanai, HI
• 1200 meter Mooring • Data Recovery via
Analog Cellular • Meteorological Sensors
on mooring float • MOBY totally
autonomous • Has batteries and solar
panels
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
MOBY is aging
• Damage from environmental causes are decreasing.
• Data loss due to random component failures are increasing.
• Changes to FCC regulations render existing data telemetry obsolete.
• Limited sample rate
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
R&O Redesign Summary Objectives
• Demonstration of Mooring Based Power System concept
• Use power system to test new MOBY components: MOBYNet
• Test new swivel/tether system mechanical operation and endurance
• Develop deployment and servicing techniques
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Communications System Design: AHABNet
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
AHAB
• Reduced size & weight • Ionomer foam float • Fiberglass frame • Low self shadowing • Double collectors • Depth adjustable • Reduced diver servicing • Drop weight for easier
recovery
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Meteorological Buoy
• Increased payload – 450 watts Solar Panels – 1200 ah Batteries – More ballast – Increase stability – Easier Maintenance
• Control System – Campbell Data logger – Cellular Phone WAN – Wireless Router LAN – Meteorological Sensors
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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Flounder Plate and Swivels
• Attachment point of tether at Mooring
• Swivel • Must be redesigned to
allow electrical conductors from Mooring to AHAB
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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
MOBY in action
• Buoy Dynamics • Vertical Orientation
due to Float/ballast • Requires Drogue
array to dampen the “bounce”
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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Buoy Motion Damper (Flopper Stopper)
• Nylon Line • Dacron “cones” • Line Length
determined by water depth, anchoring requirements
• Cones trap large mass on upstroke
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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
R&O Buoy System: Accomplishments
• Accepted delivery of mooring components in Hawaii 13 March 2006
• Completed initial testing of the integrated tether electrical system 20 March 2006
• Successful system deployment 2 March 2006 • Performed post deployment line load testing 2 March 2006 • Conducted in-situ electrical testing 2 March 3006 • MOBYNet and MOBYCam testing using tether power source
3-4 March 2006 • Performed diver tether servicing under marginal sea conditions
2-4 March 2006
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
R&O Buoy System: Outline
• System Overview • Communications system • Mooring Buoy • Radiometric Buoy • Tether – Tether Test - status • Data System
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Sunset over Kauai
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NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
System Overview
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Buoy
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Buoy Electrical System
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Buoy Electrical System
1. Controller Box Campbell Scientific Data Logger CS5000: Controls operation of the Mooring data
system Programmable operation schedule Controls power to Campbell cell modem
(1b,c) Controls power to MOBYNet Cell
modem (1h,j), Wireless Router (1g)
Data logging: battery voltages, drain currents, charge Currents Monitors and logs tether conductor
voltages and current Provides remote monitoring and control
via cellular system Monitoring and control via local
connection
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Buoy Electrical System 2. Cell modem
Cellular system to RS232 connection to CS5000 (1a) Airlink Redwing
3. Amplifier Dual band bidirectional cellular amplifier Boosts signal in fringe areas
4. Monitor/Control Electronics Interface electronics between CS5000 (1a) and Power Relays (1e) Scaling and filtering for analog inputs: Battery volts (5), Charge currents (3,4), Temperature (inside of 1, 1a) Humidity (inside of 1) Powered by CS5000 (1a) 12 volt SW (Battery 5)
5. Power Relays Switch Battery (5) power to other systems (1b,c,g,h,j) Provides switched power to systems requiring more amperage than can be provided by CS5000 (1a) 12 volt Switched Power (12v SW). Switching power to subsystems reduces overall power consumption since only the required subsystems are powered at any given time.
6. Charge Controller
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Mooring Buoy Electrical System (continued)
7. Controls Solar charge current to Battery (5) 12 Ah, 12 volt
8. Network Wireless router Interface and IP handling between Cell modem (1h) WAN and Wireless LAN. Provides multiple IP addresses for local use from the one IP of the Cell modem.
9. Cellular modem Airlink E-Raven. Ethernet cellular CDMA modem operating of Verizon Wireless. Facilitates internet access to the mooring site. Modem is operated with a static IP. Upgradeable as cellular providers change their communication protocols.
10. Amplifier Dual band bidirectional cellular amplifier Boosts cellular system signal in fringe areas
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Electromechanical (EM) Swivel
• Provides rotating attachment point for MOBY tether.
• Prevents tether from wrapping on mooring as shifting ocean currents rotate MOBY about the central mooring and watch buoy.
• These R2O modifications add electrical slip rings to the mooring, providing a rotating electrical joint to the mechanical swivel.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Electromechanical Swivel Specifications
• Mechanical – 10 ton SWL swivel – Constructed of Stainless steel
core elements, Silicon Bronze shell and Titanium fasteners
• Electrical – 4 –Slip ring conductors – 4 ampere capacity – 600 volt isolation – Underwater mate-able
bulkhead connectors – Diver serviceable tether
connections and junction boxes
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Conducting Tether • Provides connection between MOBY and main
bottom mooring. – This line must float during slack wind and current
conditions to prevent tangling with MOBY.
• Tether is oversized to maintain integrity if abraded or cut.
• The R2O modification adds wire conductors to the tether line. – These electrical conductors provide power to MOBY from
the main mooring buoy.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Conducting Tether Specifications • Mechanical
– 100-meter line length – Samson 1.5” Round Plait 12 Ultra
Blue – Samson Nylite Spool and Shield eye
termination at swivel end – PMI Everflex Bending Strain Relief
(BSR) at MOBY end – Final assembly slightly buoyant in
seawater • Electrical
– Wire construction • Alpha Wire XTRA-Guard High Flex • 4 x 1, 18 (19/30) AWG • 1.5 ohms per conductor at 300’
– SeaCon underwater mate-able connectors
– Wire free floating in kink resistant HDPE tube placed down the center of the tether braid
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Predeployment Testing Initial continuity testing
• Following delivery in Hawaii, the tether was tested for continuity and isolation. – The conductor resistance measured with a Fluke 87 DVM was 1.5
ohms per conductor, well within the manufacturer’s specification for the cable.
– A Meg Ohm Meter was not available for this test but the Fluke DVM measured an inter-cable resistance in excess of 20 Meg ohms, indicating a lack of gross shorts within the cable.
– The cable was tested again with similar results after adding the SeaCon connector terminations.
• The four EM swivel conductors and contacts were tested in similar fashion. – The slip ring conductors showed no measurable resistance or shorts. – the EM swivel conductors showed no resistance changes or dead spots
when rotating the swivel.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Predeployment Testing: Static Tension Test (1)
• We performed an initial load test of the tether line and the inner wire conductors at the dock.
• One end of the Tether assembly was secured to a substantial dock bollard, the other end to the forklift and a Dillon dynamometer.
• Continuity of the four conductors were monitored as the forklift slowly increased tension on the tether. – We estimated the working maximum MOBY drag in the water at 3000 lbs at 3
knots current. It is unlikely the tether will ever experience this load during a deployment even considering acceleration due to waves.
– Our forklift tensioner allowed us to achieve a sustainable tension of 2500 lbs with peak loads of about 2800 lbs.
• We repeated the test four times to cycle the load on the tether. • Tether elongation during the test was approximately 10 feet.
– About half this length was recovered within 30 minutes of removing tension from the line.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Predeployment Testing: Static Tension Test (2)
• The design of the tether assembly allows the wire to float within the HDPE tubing in the tether.
• The wire length is sized to allow large excursions of tether line length without stressing the relatively non-stretchy wire. – Wire movement within the tether should be less than 24”
under the expected deployment loads. • Experience with previous tethers indicates there will
be little if any additional permanent elongation of the tether line, which if excessive, could ultimately damage tether conductors.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Predeployment Testing: Divers
• The divers gained familiarity and practiced with the new system while on shore. They received instruction on the details of connector handling, cable fairleads and fasteners.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Deployment (1) • The tether was prepared and deployed using our “standard” MOBY
procedures. • The BSR/stainless steel clevis end of the tether is attached to MOBY at the
dock before loading the buoy aboard the ship. • The electrical conduit is fed through a hole in the MOBY floatation up to
the buoy deck. • Protective conduit guides the wire to the well containing the reservoir of
excess wire loops. • The wire connects to the Power Junction Box via SeaCon WetMate
connector. • This connection was replaced by a temporary shorting connector to allow
testing the wires after deployment. • The tether is hinged to the up position and secured with line to the buoy
tower for transit to the site. • The remainder of the tether is flaked on deck with the Samson eye
termination attached to the stern of the ship.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Deployment (2)
• In preparation for deployment, the tower lashings are cut and the tether is dropped to the down position.
• MOBY is deployed and the tether paid out. • MOBY, secured to the stern of the ship, is
taken under tow until it is positioned in close proximity of the mooring, where the tether is handed off to the dive boat for attachment to the mooring.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Deployment (3) • Divers make the attachment of the MOBY tether to the
subsurface mooring swivel. • For this deployment we are performing a long term mechanical
test of the EM swivel so the tether is attach to the standard mooring Flounder Plate, not the new swivel – The new EM swivel is bypassed with a safety chain to prevent loss of
the mooring if this swivel should fail. – Since the EM swivel is blocked from rotating, we cannot leave the
tether electrical cable permanently attached for this test. – The tether will be attached directly to the EM swivel in future
deployments after we gain confidence in the new components. • The divers then completed the temporary electrical connection
of the tether to the EM Swivel.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
At-Sea Testing: Mechanical • A dynamometer was used to measure the tension on
the tether while monitoring the integrity of the tether conductors under increasing line loads.
• MOBY was pulled by the ship at speeds up to 3 knots exerting a Maximum pull of 2500 lbs. – The tether tension at 1.5 knots through the water was
between 800 and 1000 lbs. – These are the maximum loads we expect the tether to
experience during a normal deployment. – The wire showed no signs of breakage or shorting (between
wires or seawater) during this test.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
At-Sea Testing: Electrical • We continued electrical testing of the tether and the
attached equipment after the divers completed the underwater connections. – The system was manually powered up and tested for proper
tether voltages and currents. – The power system on the mooring buoy provides 200 watts
of power at 48 volts to MOBY instrumentation through the EM swivel and 300’ of tether.
– We left the power system on through the night and again tested the tether in the morning before disconnecting the tether wire from the swivel and securing the loose connector loop.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
FACILITATED OPERATIONS: MOBYNet and MOBYCam
• The additional power provide by the tether system and the ability to add instrumentation to MOBY allowed us to test new and updated systems currently under development for MOBY. – Though not activated for this test, we have added a new
controller and data telemetry system to the mooring float. – For testing, we added an AXIS real time networked camera
system to MOBY. The camera system provided a suitable electronic load for the tether tests as well as a useful video data stream to test the wireless LAN.
– The Campbell data logger was configured to monitor the electrical performance of the tether and power supplies.
NOAA Research and Operations Marine Optical Buoy Design Review July 18-19, 2006
Tether & Swivel Test Report • Tether recovered during the June 06 MOBY
swap • Tether conductors damaged by fishing snag • Damaged because the EMS connection could
not be left connected • Tether repaired for redeployment • Swivel electrically intact • Swivel shows no significant mechanical
degradation