Acoustically Navigated Geological Underwater Survey

The Acoustically Navigated Geological Underwater Survey (ANGUS) is a deep-towed still-camera sled operated by the Woods Hole Oceanographic Institute(WHOI) in the early 1970s. It is the first unmanned research vehicle made by WHOI.[1] ANGUS is encased in a large 12 feet (3.7 m) steel frame designed to explore rugged volcanic terrain able to withstand high impact collisions.[2] It is fitted with three 35 mm color cameras with 400 feet (120 m) of film. Together its three cameras are able to photograph a strip of the sea floor with a width up to 200 feet (61 m). Attached with each camera are strobe lights allowing the cameras to see the ocean floor from 35 feet (11 m) to 50 feet (15 m) above.[1] On the bottom of the body is a downward facing sonar system to send the height of the sled above the ocean floor to the monitoring scientists.[1] It is capable of working in depths up to 20,000 feet (6,100 m)[3] able to reach roughly 98% of the sea floor.[1] ANGUS can remain in the deep ocean for work sessions of 12 to 14 hours at a time, taking up to 16,000 photographs in one session.[4] ANGUS was often used to scout locations of interest to later be explored and sampled by other vehicles such as Argo or Alvin.

It has been used to search for and photograph underground geysers and the creatures living near them and is equipped with a heat sensor to alert the tether-ship when it passes over one.[3] It was used on expeditions such as Project FAMOUS (French-American Mid Ocean Undersea Study 1973-1974), The Discovery expedition with Argo, to survey the wreckage of the Titanic.[3] (1985), and again in the return mission to the Titanic (1986). ANGUS is the only ROV used on both dives to the Titanic.

On Project FAMOUS ANGUS helped change scientists views of the ocean floor. It showed them how different geological formations and chemical compositions of sediments can be, disproving previous assumptions of ocean floor uniformity [5] The project also provided new insight to the theory of seafloor spreading by observing and sampling the rock formations around ridges and the horizontal formation of layers parallel to the ridge.[5]

In another 1977 expedition, with ANGUS scientists monitored temperatures over the ocean floor for any fluctuation. It was not until late at night the crew noticed temperatures rise drastically. They would review the photograph footage taken after the vehicles session.[2] ANGUS provided the first photographic evidence for hydrothermal vents and black smokers.[4] It had returned with over 3000 colored photos showing both vents as well as colonies of clams and other organisms.[2] They would later return with Alvin to take samples.

Along the expeditions scientists nicknamed ANGUS "Dope on a rope" [2] due to its durability and lack of fragile sensors. It was also given the motto "takes a lickin, but it keeps on clicken". ANGUS was retired in the late 1980s having compleated over 250 voyages.[1]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 “Ships & Technology used during the Titanic Expeditions” Woods Hole Oceanographic Institution March 1, 2012
  2. ↑ 2.0 2.1 2.2 2.3 Lindop L. (2006) Venturing the Deep Sea pp37-41
  3. ↑ 3.0 3.1 3.2 Porteaus J. (1986). VETERAN ANGUS Oceans. Vol. 19, Issue 1, 23.
  4. ↑ 4.0 4.1 Yount L. (2006) Modern Marine Science: Exploring the Deep. pp 133-136
  5. ↑ 5.0 5.1 Hammond A. (1975) Project FAMOUS: Exploring the Mid-Atlantic Ridge 'Science' Vol. 187 no. 4179, 823-825.

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