AS2014_AUV_AAR

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Overview
Exercise Name: Arctic Shield 2014 – Autonomous Underwater Vehicle
(AUV)
Exercise Date: August 8-31 2014
Sponsor: USCG Research and Development Center
Type of Exercise: Technology demonstration in Arctic environment
Funding Source: USCG
Focus: Support Arctic Shield 2014 through demonstrating utility of AUV
technology to enhance USCG oil response capability, through determination
of under-surface three-dimensional topography.
Situation______________________________________________________________
Oil spill response in the Arctic region is hampered by many factors; the most
obvious is ice and visibility of oil in and around ice. AUV technology may
assist the OSC in visually assessing conditions below the ice that may
impact movement of spilled oil, collection strategy for spilled oil,
assessment of individual targets impacted by oil such as ice bottom areas
and to access areas of oil that may persist under the ice. It will also assist in
assessing oil spill containment factors of different ice types, including those
involved in the spill. The containment factor is volume of oil that can be
contained by the under-side roughness without involving further expansion
of the under-ice slick, divided by the overall area of the slick.
Objectives____________________________________________________
1. Deploy AUV from USCGC HEALY cutter boat.
2. Deploy Tracking Buoy off USCGC HEALY
3. Observe and assess functionality of AUV around and under ice
4. Observe deployment, recovery and general operations of the AUV
5. Document observations via data capture plan.
Participating Organizations____________________________________________________
HEALY.
USCG Research and Development Center (RDC).
University of Cambridge, with Funding from the European Commission ACCESS
project.
Planning Team___________________________________________________________________
LCDR William Woityra - Operations Officer - CGC HEALY
Rich Hansen – Chief Scientist – RDC
Peter Wadhams – Lead researcher – Cambridge University
Richard Yeo – AUV operator – Cambridge University
Scot T. Tripp – AUV Lead - RDC
Operations____________________________________________________
05 Aug 2014 – RDC advanced logistics support team arrived in Anchorage
and provided the AUV shipper Power of Attorney to allow the AUV to clear
customs. The team then travel to Seward to on-load all gear to HEALY that
was shipped after HEALY departed Seattle.
06 Aug 2014 – Gavia was deployed from the beach at Seward by the
Cambridge team. All AUV gear was then loaded onto HEALY. Cambridge
team Boarded HEALY in Seward and began their unpacking and equipment
checks. Cambridge team was working to have the AUV ready to splash in
Nome.
13 Aug 2014 – A trial run with the Gavia AUV was conducted. The
Cambridge team deployed the Gavia while anchored off Nome. The Gavia
was lowered from the starboard a-frame to the Cutter Boat Large (CBL).
Because they are running the Gavia upside down to capture under ice
features, the AUV must be physically held right side up along the CBL in
order to establish communications and start the unit. The tracking buoy was
deployed off the port side. Due to difficulty stabilizing the Navigation
system, Gavia and the CBL drifted 2 miles astern of HEALY, out of range of
tracking buoy. AUV runs were attempted but the unit aborted, likely due to
currents and inability to maintain GPS locations.
14 Aug 2014 – The Arctic Survey Boat (ASB) picked up the last of the new
passengers and headed north to the Arctic ice fields.
16 Aug 2014 – The HEALY arrived in the Arctic ice fields and the 48 hour
oil tracking exercise was started. Winds preclude deployment of Dye and
oranges and grounded the Puma and the aerostat. The AUV was deployed
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at 1400. The CBL took them to a ridged ice flow. The Operator could not
get the AUV to move the propeller. Mission aborted and team returned to
HEALY. Diagnostics commenced. Loose connections were found inside the
AUV. Connections were tightened and the AUV was reassembled for
possible ops on the 17th.
17 Aug 2014 –High winds continued into the second day so the 48 hour oil
tracking exercise was postponed. The AUV was given clearance to deploy
at 1330. The AUV team was deployed on the CBL, the tracking buoy was
then deployed and the system was ready to go at 1400. The AUV failed to
initiate the spinning of its propellers. The operator initiated a restart of the
AUV (45 minutes) and re-deployed. It was very awkward to hold AUV
inverted to establish communications as there were sizable waves but the
unit started up and headed out. The tether line immediately got tangled and
the AUV aborted the mission. (the operator indicated that there was a
possibility that the AUV may have aborted prior to the tangle). The AUV
was brought back on board the boat, the operator conducted a quick reset,
and the AUV was redeployed, the Unit started and two man team began
paying out the tether. The AUV stops (aborts) and is recovered. Another
quick reset is initiated and the AUV is redeployed. The unit starts but the
tether gets tangled again, The AUV aborts, (may have already aborted). The
AUV is recovered and the CBL returned to the HEALY. The Software is
investigated and a possible code problem is corrected. The operator
reprogrammed the AUV and remade the tether payout into a bucket rather
than on a wheel. The Cambridge team is ready for ops on Monday the 18th.
18 Aug 2014 – The AUV is deployed from the ASB in the afternoon. The
team deployed close to the HEALY. A successful mapping of a ridged floe
close to ship was accomplished, with successful tracking by the transponder.
The ASB was then ordered back to the ship precluding further surveys that
day.
19 Aug 2014 – The AUV is deployed from the CBL in the morning and the
afternoon. Mapping of a heavily ridged floe was accomplished in the
morning at considerable distance from ship. The Puma flew over the ridge
that was mapped from below. In the afternoon the AUV mapped a ridged
floe closer to the ship. The tracker worked in the afternoon but not the
morning due to long range.
20 Aug 2014 – No operations were conducted on this day. The morning was
set aside for mapping under an ONR buoy if found. The HEALY spent the
morning in search of the ONR buoy. The buoy was located around noon on
a small piece of ice lying on its side. The decision was made to photo the
site and then steam south to investigate DARPA buoys. The ice with the
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ONR buoy on it was considered too small to map and the buoy will likely
melt off in a day or two. The contextual thickness distribution of the floes
around the buoy would have been of value scientifically for understanding
the buoy motion and the ice decay rate since they were probably part of a
single floe containing the buoy, This could have been better determined with
an additional under ice survey, however, operational constraints required
departure from the area. Also the decision was made not to re-launch ASB
to straighten the buoy. As a result, performance of the buoy in transmitting
wave data will be compromised for a short time until the floe is fully melted
and the buoy floats in water
Lessons Learned_______________________________________________
1.
Need to thoroughly review launch, retrieval, and operations options in
advance. Upside down AUV with tether required water level handling (i.e.
boat launch) and dedicated boat time which resulted in schedule conflicts
with the other science teams requiring boat support. This was further
complicated because there were only two qualified coxswains aboard the
ship. As a result many opportunities to obtain AUV runs using the CBL
were lost. Additional under ice maps, beyond the three that were recorded,
could have been obtained without adding dedicated ship time. Other options
such as a deck launched quick release cradle would have also allowed more
opportunities for AUV operations.
2.
Need to insure a better understanding of auxiliary gear between RDC
and science team. When science team says they need to have a tracking
buoy on a line, they may mean a 10 foot aluminum pole with a hydrophone
on the base, an inflatable buoy in the middle and a GPS antenna on the top
that needs to be weighted down and requires a team to launch. Meanwhile
the planners are thinking a buoy with a hydrophone hanging from a rope that
is lowered over the side by one person.
3.
Need to manage expectations of science teams with regards to Coast
Guard procedures and policy. Science team for the AUV was comfortable
with seeing an ice floe that looks pretty big and being able to go out on it,
based on their experience. Coast Guard policy precludes that kind of
activity and insists on conducting full ice recon prior to allowing ‘on ice’
operations.
4.
An email outlining some of the constraints of shipboard operations
should be sent out well in advance of the cruise. Specifically that there will
be time that opportunities for operations will be missed due to conflicts with
other technologies being deployed, or due to ships requirements and training
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obligations. This has been an issue between the Coast Guard and the
National Science Foundation for some time. Both sides are right but it is
important when the RDC is bringing a science team aboard the HEALY at
no ship cost to them, that they understand what the ship decides is the way it
will go. No questions, no debate. The ships command will have been
briefed of the requirements of all parties and will make the final decision.
5.
As an add on to #4, it is very important the each science team clearly
states their requirements, primary goals and other ‘would like to accomplish’
activities ahead of time. To add on requirements and activities as we are
sailing to the ice will likely result in them not happening.
Conclusion____________________________________________________
1. This particular AUV and how it was operated could have been better
prepared for this mission. Due to insurance concerns, the leased AUV
had to be tethered which hampered operations by adding another point of
failure. The complications of running the unit upside down to use bottom
looking sonar to image under ice structure put another operational
complication into the launch sequence. It was very hard for the launch
crew to maintain the AUV right side up while communications were
established prior to release.
2. This particular unit was much easier to handle than the AUV used last
year in that it was man portable.
3. The imagery from the AUV was good when the unit ran well. The top
side topography was not taken due to weather and Coast Guard
procedural issues precluding take off of the quad-copter from the flight
deck..
Recommended Future Actions___________________________________
1. The most critical recommendation is to manage science team
expectations and encourage them to consider multiple modes of
operation. Up front, let them know that there will be fog, there will be
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high winds, there are restrictions on what ice you can get on, and there
are competing requirements for limited resources.
2. AUV’s may be a good option to map under ice entrained oil but there
needs to be some real capability tested. The right sensor package that
would actually be used in an incident would be preferred. We have
not yet demonstrated a unit that can do the job completely yet. This
would include launching, having the AUV conduct a search,
messaging to the ship if oil is detected, mapping the extent of the find
and returning to the ship without a tether. Recommend that the next
AUV ops consider that as the challenge. The RDC may want to
undertake this one with their own AUV.
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