Forward By the Author
ISIS - our deep sea robot (pictured above) - is a great bit of equipment that grabs the imagination of the public and the scientific community alike. There is something about these deep diving robots exploring the deepest and darkest depth that has captivated people since the ancestors of our ROV explored the inner depths of the Titanic....
Who knows what you will find? New species never before seen, Spanish gold, giant squid or spectacular underwater features never before glimpsed.....
This article aims at looking at what ROV's are as well as a comprehensive look at our ROV - ISIS (pictured above) and the features of our ROV
Introduction to ROV's
Remotely Operated underwater Vehicles (ROVs) is the common accepted name for tethered underwater robots in the offshore industry. ROVs are unoccupied, highly maneuverable and operated by a person aboard a vessel (we do not go down in the ROV)
They are linked to the ship by a tether (sometimes referred to as an umbilical cable), a group of cables that carry electrical power, video and data signals back and forth between the operator and the vehicle.
Most ROVs are equipped with at least a video camera and lights. Additional equipment is commonly added to expand the vehicle’s capabilities. These may include sonars, magnetometers, a still camera, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration and temperature.
Construction of ROV's
Conventional ROVs are constructed with a large flotation pack on top of a steel or alloy chassis, to provide the necessary buoyancy. Syntactic foam is often used for the flotation.
Above: ISIS gets its buoyancy from two large syntactic foam blocks (pictured above, here they have been removed from the vehicle for maintenance)
A tool sled may be fitted at the bottom of the system and can accommodate a variety of sensors. By placing the light components on the top and the heavy components on the bottom, the overall system has a large separation between the center of buoyancy and the center of gravity, this provides stability and the stiffness to do work underwater.
Above: the middle section of ISIS contains the majority of electrical wiring and components
Above: ISIS Subframe contains the toolsled. It also contains space for additional systems such as the SM2000 swath system
Electrical cables may be run inside oil-filled tubing to protect them from corrosion in seawater. Thrusters are usually located in all three axes to provide full control. Cameras, lights and manipulators are on the front of the ROV or occasionally in the rear for assistance in maneuvering.
The majority of the work-class ROVs are constructed as described above, however this is not the only style in ROV building. Specifically the smaller ROVs can have very different designs each geared towards their own task. One company's ROV even has wings that allow the vehicle to move more efficiently, while being towed and/or operating on thruster power in high currents.
Science ROV
ROVs are also used extensively by the science community to study the ocean. A number of deep sea animals and plants have been discovered or studied in their natural environment through the use of ROVs: examples include the jellyfish Bumpy and the eel-like halosaurs.
In the USA, cutting edge work is done at several public and private oceanographic institutions, including the Monterey Bay Aquarium Research Institute (MBARI), the Woods Hole Oceanographic Institution (WHOI), and the University of Rhode Island / Institute for Exploration (URI/IFE).
Science ROVs take many shapes and sizes. Since good video footage is a core component of most deep-sea scientific research, research ROVs tend to be outfitted with high-output lighting systems and broadcast quality cameras. Depending on the research being conducted, a science ROV will be equipped with various sampling devices and sensors.
Many of these devices are one-of-a-kind, state-of-the-art experimental components that have been configured to work in the extreme environment of the deep ocean. Science ROVs also incorporate a good deal of technology that has been developed for the commercial ROV sector, such as hydraulic manipulators and highly accurate subsea navigation systems.
While there are many interesting and unique science ROVs, there are a few larger high-end systems that are worth taking a look at. MBARI's Tiburon vehicle cost over $6 million US dollars to develop and is used primarily for midwater and hydrothermal research on the West Coast of the US.
WHOI's Jason system has made many significant contributions to deep-sea oceanographic research and continues to work all over the globe. URI/IFE's Hercules ROV is one of the first science ROVs to fully incorporate a hydraulic propulsion system and is uniquely outfitted to survey and excavate ancient and modern shipwrecks
ISIS
Above: ISIS being lowered into the sea - the cable may look thin but its incredibly strong!!!! In addition to supporting ISIS's weight (upward of three tonnes) it also carries 3000 volts and the fiber-optics necessary to send commands to the vehicle and receive real-time video footage and data
ISIS SYSTEM
Isis is a deep-diving ROV constructed for the UK marine science community by engineers at the Woods Hole Oceanographic Institution, USA. Isis was delivered in 2003 and is a near identical clone of ROV Jason 2 operated by WHOI for the US community.
The vehicle is operated by the Deep Platforms Group, part of the NERC National Marine Facilities Division at the National Oceanography Centre, Southampton.
The Isis ROV has a depth rating of 6500m making it one of the despest diving scientific ROV's around.
The vehicle frame is constructed from a combination of hollow and structural section aluminium, welded together to form a rigid structure. The frame is corrosion protected with anodes and ground-fault detectors.
Nylon skids and 'D' rubber fenders protect the frame from impact damage during normal operations. Buoyancy is provided by syntactic foam modules (density 500kg/m3) finished with elastomeric coating bolted directly onto the vehicle frame.
Most electronics are housed in titanium pressure vessels with instruments connected to oil-filled electrical junction boxes via pressure balanced, oil-filled cable hoses.
Isis has a large front retractable tray for the collection of scientific samples (see below)
Smaller swivel trays at the sides can carry additional samples. A maximum payload of ~150kg (weight in air) can be recovered.
Propulsion is provided by six reversible 3.7kW thrusters, arranged with two thrusters each providing fore/aft, vertical, and lateral motion.
The vehicle is controlled from the surface via a tether, with three optical fibres for data and three conductors at 3kV for power, linked to a modular control room with space for three operators/pilots and four or more scientists.
This science control area includes equipment for event logging, video and data recording to a 7TB data store, record keeping and enables scientists to work directly with the pilots during survey and sampling operations.
In addition, the Isis package includes a two-container workshop with tools and spares, a winch and cable drum with 10km cable and an electro-hydraulic power unit for the winch and launching gantry (see below)
The ISIS system also includes eight guys who like to enjoy themselves!!
VITAL STATS!!!
• Length: 2.7 m; Width: 1.5 m; Height: 2.0 m; Weight: ~3T
• Max. working depth: 6500 m
• Max electric power 18 kW at 6500 m (~18kW lost in cable).
• Cable voltage: 3000V
• Maximum forward and lateral speed: 0.75m.s-1 (1.5kt).
• Autopilot functions include:
Auto depth (to +/- 1m)
Auto altitude (to +/- 1m)
Auto heading (to <+/- 1°)
• Hydraulic power unit 3.7kW for manipulators, trays etc.
• Power management between thrust, lights, hydraulics and user instruments to maximise use of power
at depth.
• Forward tray and two side trays with hydraulic actuators.
• Quartz pressure transducer for depth with precision of <0.1%.
• Acoustic altimeter to give height off the sea bed when within 200m.
• Multi-channel serial, Ethernet and video communications over optical fibre.
DIAGRAM OF THE ISIS SYSTEM
Above: The ISIS System in brief. Power for ISIS is handled by the Transformer connected to the control room which takes the ships power supply and converts it into a form useful to ISIS. The power is then passed into the tether via a connection in the winch. Commands from the control room telling ISIS what to do and the live feed from ISIS is sent via fiber optic line. Like the power these are also passed into the tether via a connection on the winch. The Winch and the Launch & Recovery system are hydraulically operated, the power necessary to operate the hydraulics (such as rams etc) in this equipment is generated using a Hydraulic power Unit. A deck unit is used to operate the Launch & Recovery System as well as the winch.
Control Van - "The Van"
The place where we control ISIS
This is where we control ISIS. the control van contains all the necessary controls for piloting ISIS and conducting science. The van contains lots of computer screens and monitors that give it more the appearance of a space craft control deck in a sci-fi movie!
Above: The control van contains a vast array of monitors showing various systems. The top row of screens show video feeds from the vehicle. The bottom screens show the various systems onboard ISIS and include the user interfaces for the Pilot, engineer and Navigator along with collision avoidance, various tracking systems and the ROV's swath system I fitted.
The control contains the data logging and recording systems for ISIS's data and video feeds. Scientific personnel sit at the back of the control room where they are able to watch the operations and view the screens whilst controlling the scientific camera onboard ISIS, logging events and taking screen captures.
Above: Scientific desk where the scientists can log events and review data
The control van usually contains three members of the ROV team. There are three "hot" seats in the control room. These are:
Pilot - This is the person who "flies" ISIS. Their called "pilots" because they operate in three dimensions just like aircraft pilots. We have two methods of controlling ISIS. The first method is using the control box, or "sticks" for short. This is a small box made up of joysticks, buttons and dials. The other method of piloting is using a touch sensitive GUI (Graphical User Interface).
Above: The Pilot Graphical User Interface that allow the pilot to control ISIS using a touch-sensitive screen. This allows much finer movements than using "sticks" and can move the vehicle in increments as small as 30cm
Engineer - The engineer’s job is to check the health of the ROV and activate/deactivate scientific and operational systems as needed. The engineer usually operates ISIS's manipulators during sampling. The engineer also performs frequent checks of each piece of ISIS ship mounted equipment to ensure that it is operating within safe levels etc - this involves taking temperature readings, inspecting gauges and listening for anything that may indicate a fault.
Navigator - The navigator is responsible for plotting ISIS's path and monitoring its relative position. The navigator liaises with the officers on the bridge to position the ship in the best position for conducting ROV operations.
Above: Scientists analyse data from ISIS during a dive
Above: ISIS video recording equipment and Data Logging Servers
HPU - Hydraulic Power Unit
The hydraulic power unit (HPU)is used to power the Deep Tow Traction Winch System and the LARS .
Deep Tow Traction Winch System
 
This part of the system is used for storing ISIS's tether as well as hauling and paying-out tether as it is required.
The traction winch system consists of a large drum of tether (around 10k), a hydraulically operated system for spooling the cable neatly onto the drum (Above right) and a traction winch.
The traction winch is two sets of wheels that are used to haul the cable. They traction winch also removes the excessive tension from the tether before it is spooled onto the drum.
The winch can be operated from both the deck (locally operated) and inside the control room (remotely operated). The system has maximum operating speed of 60m/min. However during ROV operations we rarely operate the winch anywhere near this speed
The spooling device pictured (above right) moves from side to side and ensures that the cable is neatly spooled on the drum.
Above: A aerial view of the drum (left) and the traction winch (middle of the image)
Launch & Recovery System
The ROV needs to be deployed and recovered from the sea. The ISIS Launch & recovery system does what the label says! It is responsible for picking ISIS up from her platform and placing her over the water. Once ISIS is over the water, she can then be lowered and the dive can begin. The system also acts in reverse. Hauling ISIS from the water and bringing her back onboard and placing her back on the platform.
 
Above: ISIS's LARs system on the quayside at NOC
Workshop and Storage Containers
ISIS is a self-contained system and comes complete with its own workshop, collection of spares and masses of manuals! The ISIS team members have a wealth of spares and experience at their disposable that helps reduce downtime to a minimum.
 
Above Left: Bob terminating ISIS's umbilical
Above Right: Dave overhauling one of ISIS's thrusters
Cable - "Umbilical"
ISIS's umbilical, tether or wire.... whatever you want to call it is used to send power to the vehicle. It also contains three fibre optic cables which are used to send and receive commands to and from the vehicle. The live video is also streamed via the fibre optics. The umbilical is very strong and is used to raise and lower ISIS in and out of the water.
ISIS ROV FEATURES
Thrusters
(Small little pods containg propellors that allow us to move)
Unlike a lot of science equipment we deploy ISIS is not towed and moves purely under her own power.
To do this she has six thrusters - these are similar to propellers and housed in "pods".
Two thrusters are used for vertical movement - i.e. ascent/descent. Two thrusters for fore/aft movement and two thrusters for horizontal (lateral) movement. Combinations of these thrusters can be used to rotate the vehicle in different directions.
Thrusters are by far the hardest worked part of the vehicle and have to be used constantly to fight the buoyancy of the vehicle. The vertical thrusters are used constantly throughout ascent/descent which may take a number of hours depending on the depth.
Above: One of ISIS's two vertical thrusters
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Above: ISIS's horizontal and forward/aft thrusters |
One of ISIS's forward/Reverse thrusters |
Lights
Because it gets dark down there.......
A very essential bit of kit for working in the deep sea is lights. After about 200m no light penetrates and the world starts to get darker and darker. ISIS therefore needs to carry an array of lights that can illuminate this darkness and reveal the secrets of the deep. These lights must be extremely powerful and robust
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Above: ISIS's lightbar contains a powerful array of lights used to illuminate the darkness of the deep |
Above: ISIS in the water using her aft-lights during recovery |
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Above: Closeup of ISIS's lightbar |
Above: ISIS's powerful HMI lights used to illumintae the darkness (left) and Quartz lights (Right) |
Video and Cameras
Because we need to see whats down there!!
ISIS is fitted with an array of cameras which act as our eyes on the seabed. These cameras relay the world around ISIS to us in the control room allowing us to feel that we are actually there - telepresence.
ISIS is equiped with different cameras for different purpouses. These range from high quality cameras dedicated purely for capturing the best quality images to cameras that are used purely used for flying. ISIS also has a stills camera for capturing digital images of the things we see. Framegrabs can also be taken from any of the science cameras.
Some of these cameras are fixed. Others are housed in a pan & tilt module that allows us to move the camera and see more of our surroundings. These are extremely useful for when we are conducting operations with the manipulators as they allow us to position the cameras as best as possible before attempting to sample things on the seabed.
ISIS can also be fitted with a system known as PIXELFLY. This system is a downward looking camera with two very powerful strobes which takes pictures at regular intervals as ISIS flies above the seabed. These images can then be "stiched" together to form a mozaic of the seabed. On a previous cruise we used this method to photograph the number of sea cucumbers and xenophores living on the seabed.
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| Above: A closeup of some of ISIS camera equipment |
Above: Pan and Tilt module with a stills camera and video camera mounted in tandem. Note the lasers above the right camera for measuring size |
Above: "Pilot Cam". This pan/tilt module is used by the pilot to fly ISIS. |
Above: Pan and Tilt Module minus cameras
Middle: Science camera equipped with lasers for measuring the size of samples etc. The lasers are positioned 10cm's appart
Far Right: 3-Chip High quality camera. This is an additional system that is added for high quality surveys. |
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Above: Pixefly setup includes two high powered strobes (shown above) mounted on the rear of the vehilce in combination with a camera mounted on the tool tray. As ISIS flies above the seabed the strobes are triggered at regular intervals and the camera on the front of the vehicle takes a digital image of the seabed (below).
Above: An individual pixelfly image taken from ISIS. This image shows lots of dead shells and some rocks . This image shows the alien environment encounterd at the bottom of the sea..... It almost looks like a picture taken of the moon's surface!!
Above: A series of images stiched together to form a mozaic.In this image you can see trails created by sea cucumbers and some burrows - possibly crabs
Above: Some of the pictures of life deep in the abyss that ISIS's cameras have revealed to the world. It is these pictures that capture the imagination of the public and give them an insight into life below the waves.
Above: A framegrab from ISIS's video camera showing a spare propellor on the deck of a wreck. This dived studied the effects of the wreck on the marine environment
Manipulators
ISIS's arms on the seabed
On a lot of cruises ISIS's role is "Hand-On" - i.e we are collecting physical samples from the seabed for future study, deploying experiments or just jettisoning some of ISIS's weights prior to ascent. For these operations we have two Predator manipulators that can be used.
The manipulators are highly sensitive pieces of kit and require lots off attention and situational awareness to operate. One false move and you could take out a camera, light, science experiment or damage the manipulators which cost a lot of money!
During a dive the manipulators are most commonly operated by the engineer although this may change depending on the degree of difficulty and the importance of the operation.
Although it looks fun - sampling is quite a tense operation and demands a high level of concentration and teamwork to control cameras and manipulators. The operators make it look easy but it is actually a very difficult process to pick up samples! Especially if they are the type of samples that are trying to get away from you!
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Above: ISIS manipulators are controled |
Above: The T-Bar sits inside the grove of each "hand" - see below |
Above: One of ISIS's arms is tested on deck prior to a dive |
Above: ISIS's Manipulator control unit. The arms are scaled down replicas of the actual arms on ISIS. When a portion of the control unit is moved the corresponding section of ISIS's arms moves
Above: ISIS's "Hands" are designed for different purpouses. The square grove in the hands is designed to hold a T-Bar - one of the standard ways for handling/using equipment
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Above: ISIS goes for a rock sample |
Above: ISIS Manipulators making use of a suction sample. A hoover style devce for sucking up samples - in this example ISIS is using the sunction sampler to collect shells |
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Above: ISIS manipulators using a "Box Core". The starboard arm has been equipped with a trigger ram for working with these devices. Each corer has a small trigger - when the trigger ram on the arm is extended it hits the trigger on the corer and closes the jaws - collecting a sample |
Above: A "Push Core" - a ccommon use for the manipulators is to get push cores. A tube is pused into the seabed and a "core" sample of mud and sediment extracted. |
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Above: ISIS deploying a science experiment on the seabed |
Above: ISIS siving a sample to remove mud |
Tool/Sample Tray
For storing stuff!
The retractable sample tray can be used to carry a whole range of equipment depending on the puropouse of the dive. The tray can be extended so that the arms can easily remove or add samples or equipment. When tarnsitting the tray is retracted to give an unobscured view of whats infront of the ROV
Swing Arms
For storing extra stuff!!!
ISIS has space for two sing arms - one on the port (left) side and one on the starboard (right) side. These allow additional instruments to be added to the vehicle - althought adding one or both swing arms also adds additional weight to the vehicle.
When operated the swing arms come out from the side of the vehicle and position themselves around the from of the sample tray.
Bolt Cutters
For emergencies...
Over the centuries and prior to international laws safeguarding the sea - humans disposed of all manner of junk in the sea.
Some of this junk was intentially dumped - some of it by accident. In some parts of the world the seabed is littered with man made parafanelia.
In some of the coastal regions we have dived the seabed is littered with plastic bags, cans, bottles - but most worringly for us - cables and fishing lines.
Above: This image shows some thick cabling along with various bits of rubbish - polystyrene cups, plastic bottles and plastic bags
Nets and Lines from fishing boats become stuck on thse seabed and have to be cut loose these then fall to the seabed.... waiting
During ROV operations we keep a vigilant lookout for all hazards that may trap ISIS.
However, in the event of entanglement we are equipped with a set of extremely powerful bolt cutters that could sever most cables or fishing lines up to 3/4 inch thick.
Above: Bolt cutters like ISIS's are used to cut a thick piece of disused cabling caught on the seabed.
ISIS Team Faces
Trained ISIS Operators
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Dave - "Turnip" |
Will - "The Wilderbeast" |
Simon - "Rodney" |
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James - "The Stowaway" |
Leighton - "Bouncer" ......As Needed!! |
Bob |
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Pete |
Dave |
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ISIS SCIENCE EQUIPMENT - PAST CONFIGURATIONS
Above: Ok, its not like when you see publicity pictures of fighter jets with its payload in front of it! Here is a picture of some of the most common weap.... err science equipment we use on ISIS. LTR: Sample net, large box corer, small box corer, canvas bag, push core and another mesh sample scoop
Above: Twelve small push-cores on the left, the centre contains 6 larger push cores, another 6 smaller push-cores on the right. A heat probe is fastened on the front of the vehicle (with the point resting in the yellow cylinder). Just behind this is the pixelfly camera. Weights have been fastened to the front of the vehicle.
Above: 12 small push cores on the left with four large box-corers in the grey boxes. To the right of these boxes and just visible are the bolt cutters and the pixelfly camera
Above: Six small push-cores on the left. Behind the push cores is a "bio box" used for storing live samples. In the centre of the tray is a single weight. To the right of the weight is another box containing a fine mesh scope for picking up samples. Another larger scoop is located in the black box on the right of the basket. Behind this box is the bolt cutters and a tube containing a small saw.
Above: This basket configuration has 24 small push cores and a "Suction Sampler". A device similar to a hoover. Samples are "sucked up" and stored in a sample pot. These sample pots can be rotated to store samples separately
Above: SM2000. This device is used for mapping the seabed and is usually located in the starboard wing arm position (when the arm is removed). When the swath system is added ISIS is not capable of many other operations due to the vulnerability of the swath head which could be easily damaged during sampling on the seabed
Above: Rock sampling configuration. Two large sample baskets colour coded to identify each sample slot easily - along with two smaller sample boxes behind.
Above: ISIS has been equipped with a magnetometer supplied by the scientific party during cruise JC021
Above: ISIS has also been the test platform for a wide range of prototypes - like this aqua sampler used to take samples of water at different depths and store then in small sample bags.... which in this case were the same sort of bags used to store blood!! |
