Feature ArticleSurveyor, Sampler For Deep-Ocean Operations
HyBIS, showing Hydro-Lek five-function manipulator in stowed position.
The HyBIS concept was originally developed in collaboration with the National Oceanographic Centre (NOC) in Southampton, England, to survey and interact with the deep-ocean floor without recourse to expensive and complex work-class ROV technology and specialist crew. Unlike a conventional ROV, HyBIS does not have any floatation; rather, it is suspended by its umbilical cable directly from the ship with the advantage that it can recover or deploy a payload up to its own weight of 750 kilograms.
Measuring 2.2 meters high, 1.4 meters wide and 1.5 meters long, HyBIS is a fully modular plug-and-play system comprising the command module, which carries the power management, cameras, lights, hydraulics, thrusters and telemetry; and a variety of lower hydraulic and mechanical tooling modules, which consist of a sampling grab, a manipulator and tool sledge, a winch for instrument recovery, and an ocean bottom seismometer (OBS) and ocean bottom electromagnetic receivers (OBEM) deployment module. All tooling modules are able to be separated on command, allowing the tool module or payload to be accurately deployed or, in the event of an emergency, jettisoned.
The Command Module
The command module is an open-chassis structure with a footprint of 1,700 by 1,450 millimeters and height of 930 millimeters, and carries all hydraulic and electrical power and distribution. Fabricated from 316-grade tubular stainless steel, the cross-braced open-frame structure ensures an even spread of the load across the chassis that in turn forms the template for the docking system to which the various tool modules are attached. The suspension point is adjustable in two horizontal axes to allow for changes in center of gravity when different tool modules are attached. Attached to the command module are two three-phase thrusters, two hydraulic power packs, two hydraulic valve packs, two dry space pods, an oil-compensated transformer, three cameras, several lights and a hydraulic pan and tilt system.
The system is operated from a 7-kilowatt, 380-to-440-volt, single-phase power source at the surface via the umbilical cable. All three-phase power and control supplies for lighting and instrumentation are contained in 6,000-meter-seawater housings. Two reversible thrusters, which are oil-filled and pressure-compensated, produce 40 kilograms of thrust from 1.5-kilowatt motors and are generally able to provide a radius of operation of between 3 and 10 percent of water depth. HyBIS control is via a fiber-optical link that carries all command telemetry for remote operation of all hydraulic and electrical functions, including switching for cameras and other ancillary equipment (e.g., television cameras and lighting).
The Tooling Modules
Bulk Sample Module. The basic tool module comprises a clam-shell grab with a 0.3-cubic-meter capacity for collecting samples of small rocks or seafloor sediments with a 30-centimeter penetration depth. Fabricated from aluminium, with stainless steel semicircular braces around the outside of each shell, the grab has a footprint of 0.5 square meters (1,000 by 50 centimeters). It is mounted in an open chassis fabricated from 316 stainless steel tubing and stands 900 centimeters tall. Its upper square frame docks with the lower square frame of the command module via the hydraulic release pins, allowing for it to be jettisoned if required. Four hydraulic rams drive the grab shells with a closure force of 30,000 newtons.
The grab module has been used by NOC to collect geological, biological, gas and other chemical samples from more than 40 separate sites. In 2010, scientists used HyBIS on an expedition in the Cayman Trough to locate and study a new species of shrimp at a depth of 5 kilometers, which they named Rimicaris Hybisae after the vehicle they used to discover it.
Hydro-Lek Manipulator Module. Hydro-Lek has developed a tool sledge module in conjunction with the NOC, which comprises a Hydro-Lek five-function manipulator arm and a retractable sample tray that has top and bottom rollers on both sides that are located within tubular rails. Fabricated from stainless steel and surrounded by stainless-steel mesh, the tray retracts into a drawer with a stainless-steel mesh top. This ensures that the samples are fully secure within the retracted tray to prevent their loss or damage in the splash zone when the HyBIS is being recovered.
Attached to the front lower starboard side of the tool sledge is the HLK-RHD5 five-function manipulator arm, with an 80-kilogram lifting capacity (when actuated with 160-bar hydraulic pressure) at its full reach of 943 centimeters. It has a continuous 360-degree rotating jaw, with embedded 12-millimeter-diameter cable cutter. The arm is located on a slew plate, mounted 15 degrees from horizontal such that the arm can reach the seafloor in a 270-degree arc in front of the vehicle, as well as reaching upwards to within 30 degrees from vertical. Because the hydraulic valve packs do not have flow control, the operating hydraulic pressure supplied by one of the two valve packs is reduced to 60 bar. This enables relatively slow, and hence fine, control of the manipulator arm and jaw. The option remains to activate the second hydraulic pump, which is set to 100 bar, to increase the capabilities of the arm's functions, allowing heavier lifting capacity and jaw-closure pressure.
Instrument Recovery Module
HyBIS has also been required to recover relatively heavy instruments from the seafloor. One of these was a 4-tonne benthic observatory deployed in 400 meters of water in the Arctic in August 2011 off Svalbard, Norway. The ship used was the RRS James Clark Ross, which is operated by the British Antarctic Survey, a division of the Natural Environment Research Council (NERC). Both the lander and ship from which HyBIS operated belong to NERC.
Limitations set by the vessel operator for this task included a restriction on deployment of more than one umbilical cable to be deployed over the side of the ship at any one time. As a result, a solution was developed that would involve the HyBIS command module deploying a lander recovery module carrying a passively driven drum of 600-meter-long lifting with a 4,000-kilogram safe working load and 200,000-newton breaking strain. To continue this article please click here.
Dr. Bramley Murton is a geologist at the National Oceanography Centre, Southampton, England. With more than 20 years' experience researching the deep-ocean floor, he is widely recognized as an expert on the formation of oceanic crust and its hydrothermal mineral resources. Together with Jo Garrard of Hydro-Lek, he developed the HyBIS technology to enable geologists to interact with and work on the deep seafloor in a readily accessible way.
Wendy Glover is head of marketing for Hydro-Lek, based in Wokingham, England, where for the past three years she has been responsible for developing and running public relations and marketing plans. A language and business graduate from Leeds University, Wendy has more than 30 years' experience in sales and marketing across a number of industrial sectors.