CRUISE REPORT
Cruise Number: 02-BV-02
F/V Big Valley
Area of Operation:
From
Itinery: Depart
Participating Organizations: NOAA/PMEL/OERD-2
Chief Scientist: William
J. Floering (NOAA/PMEL/OERD-2)
Cruise
Objectives: To recover damaged moorings in
Summery of
Operations: During the Sept. /Oct. cruise on the Canadian vessel Laurier we were
unable to recover one mooring in
On rather short
notice we contracted the 100 foot fishing vessel
The wind, surface
and bottom currents in these passes made it difficult at best for the vessel to
remain stationary over the target area and greatly limited the maneuverability
of the small ROV. Because the currents
were high when we arrived at Amukta pass we decided to use a clump weight with
sonar and grapple hooks attached. We
were hoping that we could home in on the vertical mooring string with the sonar
and then snag it with the attached grapple hooks. The tugging on the down wire as the waves
passed the ship and the currents made it impossible to keep the sonar level
enough to get accurate readings. When
the down wire weight tilted so did the attached sonar, rather then pinging out
in front of the weight you would ping off the ocean bottom or towards the ocean
surface.
From current
predictions provided by OERD-2 we were expecting a favorable low current
environment in Seguam pass. The
sonar/grapple idea was abandoned and we steamed 3 hours west to
At Seguam pass we
did a number of drifts over the mooring site while ranging on the release to
narrow down our search area. Once we had
a good idea where the release was and what our surface drift was going to be,
we deployed the ROV on about 200 feet of umbilical tether, then deployed the
down weight on a wire with the ROV umbilicus and spectra line attached to the
wire. The down weight was lowered to
just above the ocean bottom. Attached to
the down weight and to the ROV was the Trackpoint system that acoustically
gives you the location of the ROV and the down weight relative to the
vessel. Mounted on the front of the ROV
was a
Once the ROV was
deployed, with a little searching we found the anchor, release, wire, and
temperature sensors for the
We steamed east to
the Amukta pass mooring site. The ROV
was deployed but before we were able to attach the mooring the wind picked up
to 50 knots and we were forced to seek anchorage for 2 days. Once the weather subsided we returned to the
Amukta mooring site. After waiting 6-8
hours for the currents to drop below 1.5 knots we successfully deployed the ROV
and recovered the Amukta Pass ADCP mooring.
Following the recovery an ADCP mooring was deployed at the same
location. The EdgeTech release was
shipped to PMEL to determine why it failed.
Following the
mooring operations we steamed east to
Mooring Locations:
02-AMP-3A 52 24.00 N
171 55.00 W 310 meters
02-SM-3A 52 07.996 N 172 25.008 W 164 meters