Main Page | Web Tools | Site Map
An Introduction to Fisheries Acoustics
Acoustics | DEIMOS | Ecology and Management |
Current Research Topics | Previous Research Topics
A listing of published acoustics papers and reports | Publications | Reports
The members of the FAR Lab | Current Members | Lab Alumni | Lab Events
Links | Other acoustics related sites | Press articles

DEIMOS Deployment

small logo
Deepwater Echo Integrating Marine Observatory System

John Horne, David Barbee, and Dick Kreisberg


Transporting, placing, and connecting an instrument package in nearly 900 m of water is not a trivial task. The science team and ROV pilots worked together to plan the details of deploying DEIMOS from the RV Point Lobos using the ROV Ventana. This included modifying the bottom of the DEIMOS sled to fit snugly on the front porch of the ROV. It also meant fabricating a three-point harness to be able to move DEIMOS off of the sled and, one day, to recover the package.

Rewinding the cable
ROV pilots Knute and Mike expertly loop the cable so that it will unwind without kinks. David takes up the cable slack and protects the in-water connector.

The cable that connects DEIMOS to the MARS node was problematic. The ROV crew noticed that the cable would not unwind without creating kinks. Kinks could lead to fractures if the cable was stretched tight. After working with us, the crew rewound the cable to minimize kinks.

When the Point Lobos returned Wednesday afternoon from deploying another MARS project, we moved DEIMOS to the ship. The crew re-examined the instrument package and finalized a plan for deploying DEIMOS from the front porch of the Ventana. Once they were satisfied, we left DEIMOS secured to the Ventana for the next day's mission.

Point Lobos DEIMOS on the Ventana
Left: The RV Point Lobos in port at the MBARI wharf.
Right: ROV pilot Knute Brekke secures DEIMOS to the front porch of the Ventana.

The Point Lobos steamed for 2 hours before reaching the MARS science node on Smooth Plane. Medium winds made for an interesting ride on a boat with a well deserved reputation. After one last inspection, the Ventana was lifted overboard and released from the crane. With all systems go, the ROV began diving to the sea floor while the crew piloted it from the ship.

Ventana being lowered into water Ventana in the water
Left: The Ventana is lifted from the deck of the Point Lobos and lowered into the water.
Right: After a bouyancy check, the Ventana began diving for the bottom.

After a long trip down to the MARS node, the Ventana was piloted 40 meters to the East. DEIMOS was gently set on the flat bottom in an upright position. The ROV manipulated DEIMOS using two robotics arms. One arm is very strong. The second arm has very fine control for manipulating delicate objects.

DEIMOS underwater
Left: DEIMOS lifted from the front porch of the Ventana onto the sea floor.
Right: DEIMOS resting on the sea floor. Note that the front of the sled is sitting in very soft material. © 2009 MBARI

Once DEIMOS was oriented so that the transducer faced north, the drawer on the Ventana sled was opened and the cable was slowly played out until the ROV was back at the MARS node. The ODI underwater cable connector was then plugged into a science port. This is a very delicate process, since the connector must be positioned carefully in 3D space using only the cameras mounted on the ROV.

MARS trawlproof node
The MARS node sitting at 900m below the surface of Monterey Bay. The white arrow indicates the science port into which DEIMOS is connected. © 2009 MBARI

After successfully connecting DEIMOS to the MARS node, the power was turned on. A few tense moments pass, and voila! DEIMOS began immediately to transmit and receive acoustic echoes. As the ROV Ventana passes over the package, we saw a large echo from the vehicle. DEIMOS is definitely working. Time for the Ventana to return to the surface.

Ventana being washed
The Ventana is rinsed with freshwater after completing operations for the day. Note that DEIMOS is not on the front porch anymore!
Previous: DEIMOS Testing              Next: DEIMOS Data
earch was made possible by the University of Washington's School of Aquatic and Fishery Sciences, Kongsberg Simrad, and the Monterey Bay Aquarium Research Institute.

©2010 Fisheries Acoustics Research