Hull Inspections of USNS
Mercy |
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On
April 23 2004, LinkQuest, worked with Deep Ocean Engineering
of San Leandro, California, to demonstrate LinkQuest's
PinPoint 1500 acoustic positioning system to US Navy at the US
Naval Station, San Diego, California. A Phantom HD2 ROV,
installed with the PinPoint transceiver, was used to inspect
the USNS Mercy hospital ship docked in the Naval Station. Two
PinPoint transponders hanging from concrete docks at the pier
were used as positioning base stations.
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USNS
Mercy is a 69,000 ton oil tanker converted US Navy hospital ship.
The length of the ship is 894 feet. This ship was docked at
naval pier 1. The port of the ship was about 2.5 meters from
the dock. The bow of the ship was about 15 to 20 meters from
the dock. The starboard of the port was about 150 meters from
the dock. The water depth was about 5 to 8 meters in the
harbor during the demonstration.
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The
PinPoint positioning system was used to guide the ROV to
inspect the port of the ship at fixed depth. A Naval EOD
support boat circled around 30 to 50 meters from the bow and
starboard of the ship to test the performance of the PinPoint
under severe ship noise condition. The PinPoint system
provided highly robust and accurate positioning of the ROV
under these conditions. The repeatability of the positioning
system was also validated by piloting the ROV and revisiting
points marked by X, Y, Z values on the plot in the positioning
software. The ROV returned to the same physical location
repeatedly without error.
The ROV
was also used to inspect the bottom of the USNS Mercy where
the ship bottom was about 2 meters above the sea bed. The
PinPoint system provided excellent position fix.
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As a final test of the extraordinary
robustness of the PinPoint system, the PinPoint system is used to track the Phantom ROV 2 meters underwater at the ship's port
where the gap between the ship's hull and the concrete dock is
merely 2.5 meters. There were also a few large floats in the
gap. The PinPoint system tracked the ROV reliably during the
inspection demo at the port.
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©
LinkQuest, Inc. 1999 Last Updated November 2004
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