Being on the E/V Nautilus is an incredible experience for anyone interested in ocean exploration. We were there to shoot a PBS NOVA episode being produced by Lone Wolf Media and featuring Bob Ballard, as well as wreck diver and U-boat expert Richie Kohler. Nautilus is home to both a very talented team of people and cutting edge technology for exploring the deep ocean, still one of the least documented parts of our planet. One of the key elements to this equation are the remotely operated vehicles (ROV’s) that are the main tool for transporting cameras and scientific instruments to their targets. When I arrived on board, I was surprised to see the two ROV’s being used in tandem, Hercules and Argus, but all became clear as I saw how these two vehicles work together to pull off incredibly challenging missions that would be almost impossible for one unit to achieve by itself. These missions often include exploring wrecks that can be festooned with cables and debris, each obstacle waiting to snag an ROV at depths where help is impossible to find. One mistake could mean the loss of a vehicle worth millions of dollars.
This system is capable of exploring depths up to 4,000 meters (!3,000ft). Each of the ROVs has its own suite of cameras and sensors that receive electrical power through a steel wrapped cable ( connected to Argus ) that also carries a ﬁber-optic cable and transmits data and video back to the ship. Looking like Mission Control from a space mission, ROV pilots and video technicians work in shifts to control the vehicles from a room aboard the ship. Each trip is run with military precision, there is no room for error. With deployments being complicated, and depths so great, some the dives can last more than three days. Targets can include anything from ancient shipwrecks to deep sea hydrothermal vents.
The reason for having two ROV’s in tandem became clear as soon as we reached our first target, the German U-boat 166. The heavier steel cable connects the ship directly to Argus. Essentially it floats beneath the ship and has limited capabilities to maneuver. But the tether also transmits power to Argus, as well as carrying the video signals and data controlling the two units. From there, Hercules (idenditifed by yellow floatation) is attached to Argus via a more flexible 150m cable. This enables Hercules to travel in any direction with great precision, not encumbered by the heavy tether. This is essential when exploring a complicated wreck site strewn with cables hanging from a masts, or fishing nets caught on the debris. With just the view from Hercules, it would be all too easy for the vehicle to become completely entangled. That is where the camera on Argus comes in. Looking down from above and on to Hercules, the video feed allows the pilots to see where it is in relation to the wreck and any obstacles. At any time, therefore, the pilots can see directly in front of Hercules to see their target, but also the wider scene from Argus to identify any hazards.
Hercules is equipped with a main high-definition video camera, four HMI lights, two manipulator arms, and a variety of oceanographic sensors and samplers, including a suite of high-resolution mapping tools. It weighs about 5,200 lbs in air and can deliver approx. 150 lbs of samples or tools to and from the seafloor.
For more information you can also go to the Nautilus website page for “Herc”, learn about the unit but also view the live video stream.
Argus was first launched in 2000 as a deep-tow system capable of diving as deep as 6000 meters. As described, it now typically used in tandem with Hercules, where it hovers several meters above in order to provide a bird’s-eye view of Hercules on the seafloor. It can however work as a stand-alone system as a towed-body instrument for large-scale deepwater survey missions. Sidescan sonar looks out on either side of the vehicle up to 400 meters total swath. Argus also has its own page at the Nautilus website.
Argus (Photo- David Wright)
For the engineers, here are the specifications on the two units.
ROV Hercules Specifications
Depth Rating 4,000 meters (13,123 feet)
Air Weight 2400 kg (5200 lbs)
Video 1x 3-chip High Deﬁnition cameras w/zoom, pan & tilt
1x Standard Definition pan & tilt camera
5x Standard Definition cameras
1x stereo high-resolution still-camera system
Lighting 4x 400W HMI, 2x 250W incandescent
Navigation Tracklink 5000 USBL acoustic position RDI acoustic Doppler velocimeter (600 & 1200 kHz); Ixsea OCTANS gyro; DVLNAV navigation software
Manipulators Kraft Predator, ISE Magnum 7-function
Sonars Mesotech 1071 series proﬁling sonar (300 kHz)
Imagenex 881A proﬁling sonar (600 kHz)
Tritech Super SeaPrince proﬁling sonar (600 kHz)
Sensors Sea-Bird FastCAT 49 CTD
WHOI high-temperature probe
Sampling Tools Suction sampling system: 2x 8-liter acrylic buckets
“Snuﬄer” jet-suction excavation system
Suction-cup artifact recovery tool
2x sample bays, conﬁgurable with sealed biological boxes
Geologic boxes, various crates and containers
ROV Argus Specifications
Depth Rating 6,000 meters (currently limited to 4,000 meters by cable length)
Air Weight 1800 kg (4000 lbs)
Video 1x High Deﬁnition w/ zoom & tilt, 3x SD cameras
Lighting 2x 1200W HMI, 2x incandescent
Sonars Mesotech 1071 series proﬁling sonar (600 kHz)
Tritech SeaKing subbottom proﬁler (20/200 kHz)
Edgetech 4200 HF sidescan sonar (300/500 kHz)