The Acoustically Navigated Geological Underwater Survey (ANGUS) was a deep-towed still-camera
sled
A sled, skid, sledge, or sleigh is a land vehicle that slides across a surface, usually of ice or snow. It is built with either a smooth underside or a separate body supported by two or more smooth, relatively narrow, longitudinal runners ...
operated by the
Woods Hole Oceanographic Institute (WHOI) in the early 1970s. It was the first unmanned research vehicle made by WHOI.
ANGUS was encased in a large steel frame designed to explore rugged volcanic terrain and able to withstand high impact collisions.
It was fitted with three
35 mm color cameras with of film. Together, its three cameras were able to photograph a strip of the
sea floor
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
with a width up to . Each camera was equipped with strobe lights allowing them to photograph the ocean floor from above.
On the bottom of the body was a downward-facing
sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...
system to monitor the sled's height above the ocean floor.
It was capable of working in depths up to
and could therefore reach roughly 98% of the sea floor.
ANGUS could remain in the
deep ocean
The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low tempe ...
for work sessions of 12 to 14 hours at a time, taking up to 16,000 photographs in one session.
ANGUS was often used to scout locations of interest to later be explored and sampled by other vehicles such as
''Argo'' or
''Alvin''.
ANGUS has been used to search for and photograph underground
geyser
A geyser (, ) is a spring with an intermittent water discharge ejected turbulently and accompanied by steam. The formation of geysers is fairly rare and is caused by particular hydrogeological conditions that exist only in a few places on Ea ...
s and the creatures living near them, and it was equipped with a heat sensor to alert the tether-ship when it passed over one.
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''.
(1985), and again in the return mission to the ''Titanic'' (1986). ANGUS was 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
The project also provided new insight to the theory of
seafloor spreading
Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
History of study
Earlier theories by Alfred Wegener ...
by observing and sampling the rock formations around ridges and the horizontal formation of layers parallel to the ridge.
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 vehicle's session.
ANGUS provided the first photographic evidence for
hydrothermal vents and
black smokers.
It had returned with over 3000 colored photos showing both vents as well as colonies of clams and other organisms.
They would later return with
''Alvin'' to take samples.
Scientists nicknamed ANGUS Dope on a rope
due to its durability and lack of fragile sensors. It was also given the motto "takes a lickin' but it keeps on clickin'". ANGUS was retired in the late 1980s, having completed over 250 voyages.
References
External links
Project FAMOUS: Exploring the Mid-Atlantic Ridge{{WHOI-Ships
Oceanography