Ask a remote-operated-vehicle (ROV) aficionado what industries these handy little tools have had the most impact on, and the answers will be varied and interesting. Some will immediately name fisheries and aquaculture, where ROVs let even small operators put mobile, flexible, sensor-enhanced eyes on even their most remote underwater operations. Others would favor the transportation industry, where ROVs make major contributions to port security and vessel hull inspections. Relatively few people, however, unless they had industry knowledge backing them up, would name one of the industries where ROVs have had a major and still growing impact: energy production.
To be sure, the energy market is an enormous and enormously varied set of operations, and it is true that ROVs play a small or nonexistent role in many of the industry’s subfields. Nobody expects ROVs to be a major player in coal mines, for example (though they are handy in investigating flooded sections of mine, a very hazardous condition where nobody wants to risk a human diver…)
There are three basic areas in which ROVs play a major role: installation and investigation of offshore windfarms. Installation and investigation of the hydraulic systems of nuclear plants, and inspections of dams – many types of dams, of course, but most relevant here are the major construction achievements that produce local electrical generating capacity, i.e. hydropower.
You may notice something rather fundamental about these three parts of the energy industry: they are all carbon-neutral or low-carbon energy production systems, and thus are important tools in reducing global warming.
Hydropower is among the oldest approaches to renewable energy, and is far older than its relatively recent adaptation to produce electricity. Preindustrial civilizations have used the power of running water to pump water uphill, to irrigate crops, and to turn machinery. In modern times, giant hydroprojects like the Hoover Dam produce thousands of megawatts of electrical power, enough to serve millions of households, at a relatively reasonable environmental cost. Unfortunately, while the Earth has plenty of water and plenty of gravity, the requirements of hydropower for particular configurations of these resources means that the generating capacity of the natural world is more or less known, and fixed – and the “good spots” are already taken. Hydropower produces more than 1,000 Gigawatts (that’s a thousand megawatts) – about a sixth of the world’s total generating capability. Because hydropower generally requires building large dams that hold enormous quantities of water – usually conveniently located just upstream of enormous population centers – the safety monitoring and maintenance of the dam system is of the utmost priority. ROVs, of course, bring the costs of maintenance and inspection down drastically, further increasing the economic sensibility of hydropower as one of the major components of the global energy economy.
In the eyes of many, nuclear power could not be more diametrically opposed to hydropower. But in fact, depending on your point of view, a number of fundamental similarities are clear. First, although neither hydropower or nuclear power are free of environmental costs, those costs tend to be fixed cost that arise from having the industry exist at all, not costs that double every time the installed generating base doubles. Second, both nuclear and hydropower are baseline generation systems, meaning that they are always available. Third, both forms of generation tend to have catastrophic, but extremely rare, failure cases. If Hoover Dam bursts, an entire downstream city will die. If a Soviet-era nuclear plant goes critical, half of Eastern Europe could be irradiated. This combination of low expenses, high reliability, and rare disaster cases encourage us to think of these forms of power as being *perfectly* reliable, when in fact they are anything but. How to push those systems towards increased stability? Again, with more frequent and more capable monitoring.
If hydropower is the revered ancestor, still trusted but unable to keep up with the demands of his hungry children, and nuclear power is the disliked but economically essential rich cousin whose fortune keeps the family from starvation, then surely offshore windpower is the angsty, emotionally involved younger sibling – a source of infinite potential and hope for the future that is, unfortunately, wrapped in often problematic presentation right now. Windpower has an enormously high undeveloped potential for power generation, at an environmental cost that is minimal if not negligible. (Just the surface layers of the atmosphere could generate 20 times the current TOTAL human energy usage.) Unfortunately, as with hydropower, the easy spots – that is, the places where a huge turbine farm isn’t out of place - are being used for other projects. And that means that wind power has to move offshore, where the real estate tends to be heavily discounted on account of being a thousand feet beneath the ocean. And although it’s possible for us to build infrastructure in the ocean on this scale, it’s not cheap and it’s not easy – and again enter ROVs, keeping costs down, keeping human divers out of harm’s way, and providing more information for project engineers about safety and performance.
It would be an exaggeration to say that without ROVs, we can’t get to a lower-carbon, warming-mitigated world economy. But it wouldn’t be an exaggeration at all to say that ROVs are making major contribution to the energy economy’s attempt to get us over the carbon-footprint hill and into the low-carbon, high-energy promised land.
One of the most common uses for commercial underwater remote-operated vehicles (ROVs) is in conducting inspections of water tanks, ship hulls, and submerged infrastructure such as bridge components or dams. A critical element of these inspections is measuring the thickness of metal components like hulls or girders. How do ROVs conduct this type of measurement?
On the Aquabotix Endura line of high-performance commercial ROVs, we offer the Cygnus NDT Metal Thickness gauge as an optional accessory. These gauges use ultrasound technology to measure the thickness of metal objects underwater. By emitting an ultrasonic beam into the surface of the metal and analyzing the return sound, the Cygnus NDT can measure metal of thicknesses up to 10”, even through coatings such as paint up to 0.787” thick.
The Cygnus NDT is extremely easy to use. The included CygLink software allows the ROV operator to visualize the tool’s measurements remotely on the video feed. To make things even easier, the optional Cygnus Probe Handler automatically aligns the probe to the wall or item being measured, with 15 degrees of movement, even if the operator has not perfectly approached the measurement subject.
Tools like the Cygnus greatly enhance the utility of our Endura ROVs. As ROVs take on more responsible roles in things like underwater inspections, the need for tools such as the Cygnus will continue to grow.
The concept of “the last frontier” is one frequently bandied about by popular writers. Whether the phrase refers to the Western frontier of American expansion in centuries past, or specific “hot” fields of scientific inquiry, or the vast expanse of interplanetary and interstellar space, the concept is always the same: there’s one Great Mysterious Place left for us to go, and (“fill in the blank”) is that Place.
It turns out that frontiers don’t work like that. It’s true that sometimes a constraint closes off further exploration of a place; once the American border reached the Pacific Ocean, there wasn’t a whole lot of Old West left to “discover.” (The people who had already been living there for 10,000 years probably knew that.) But it’s far more common to find that expansion and discovery are never-ending, that new exploration is always worthwhile, that there is always something more over the horizon.
Or under it. For centuries – actually, for millennia - the world ocean of our planet has been a vast empty space on the map. Explorers skimmed its surface looking for new land-based opportunity, and merchants and warriors fought along its peripheries for access to new markets and new resources on the lands that the ocean adjoins. What lay beneath has been a murky question mark – a question mark hard to find, harder to reach, and almost impossible to exploit.
Technological progress is rapidly revising that predicament. The earliest historically-attested submersible vehicles, built in the 1600s, could attain depths of less than a hundred feet, in calm waters, for periods of a few minutes at best – and couldn’t see or do much while they were down there. Today’s bathyspheres, submarines, and advanced remote-operated vehicles (ROVs) have reached the uttermost depths of the ocean floor, can move at up to 40 miles per hour underwater, can stay submerged for weeks or even months, and can visualize and interact with environmental features and objects with a huge variety of tools. The ocean, while not “the last frontier” (because we aren’t likely to run out of those), is now a frontier which is eminently accessible.
It’s a frontier with resources that humanity desperately needs. The potential is almost infinite – fully three-quarters of the surface of our world is under the ocean. And although much of the ocean floor is theoretically “barren” – not much growing there, not much living there – there are subsurface resources almost beyond cataloguing. In fact, we haven’t even begun to catalogue them – they’ve been too hard to reach! But as that is changing, the potential for energy resources – oil and gas just to start, although uranium and thorium are more likely to be long-term contributors to the global economy – is vast. Already, about a sixth of US oil production comes from offshore and the numbers are building quickly. Deep-water oil formations have barely begun to be explored, and although there are environmental considerations, the ocean is likely to produce the majority of world energy needs within our lifetimes.
There is also tremendous potential for health and wellness from the undersea environment. In today’s pharmaceutical environment, many dramatic developments in new treatments and new drugs come from exploitation of newly-discovered species. For example, a promising breast-cancer drug is under development from a species of Japanese black sponge, while a bacteria found in the Bahamas has been shown to produce compounds that can be used to produce antibiotics and cancer-fighting drugs. What’s even more exciting is that an estimated 90% of oceanic species have not yet been discovered or catalogued – the extent of this incredible harvest of potential medical advances is literally waiting to be discovered.
In 2016, the Expedition and Education Foundation, an anonymous charitable organization established to support marine research, funded the University of Southampton’s Black Sea Maritime Archeological (MAP) Project, the largest project “of its type ever undertaken.” This project was designed to survey the Bulgarian waters of the Black Sea, where thousands of years ago, large areas of land were submerged due to rising sea levels as the last ice age was ending.
The Black Sea was much smaller 12,000 years ago, and the project was designed to study what significant historical treasures were inundated by water, as glaciers melted and sea levels rose, and how these rising waters affected the human populations along the shorelines of the Black Sea.
John Adams, of the University of Southampton, led the team of archeologists and researchers in this study. The main instruments used to map the Black Sea floor were two specially designed ROVs or remote operated (underwater) vehicles. These ROVs are basically tethered underwater devices with instrument arrays, and are unoccupied and highly maneuverable. They are operated remotely from the mother ship, in this case, the Stril Explorer. On this expedition, MAP archaeologists lowered the two ROV’s to hunt for ancient shipwrecks and lost history.
When interviewed, Dr. Pacheco-Ruiz of the University of Southampton said he was watching the monitors one night in September when the ROV lit up a large wreck in a high state of preservation. “I was speechless,” he said. “When I saw the ropes, I couldn’t believe my eyes. I still can’t.” He was describing a beautifully carved, perfectly intact rudder with a coil of ropes hanging off one of the ships timbers. At the depths of this discovery, the oxygen levels are so low as to prevent any microorganisms from feeding on the wood timbers.
The remarkable color images of these wrecks are a result of the union of the ROV’s 2D images and cutting edge software, which uses photogrammetry, turning thousands of 2D images into 3D renderings. These are translated into the phenomenal final renderings of these wrecks, which look like actual photographs. The tethered ROV cameras shoot video and still photos using distance information from advanced sonars, with measurements often less than a millimeter. The software layers these images to produce incredibly realistic 3D digital models of entire shipwrecks that would normally only be barely seen from the top in the visible light spectrum.
The ships have been determined to be from the 9th century through the 19th century, spanning a thousand years of sea trade and travel. Goods traded on the Black Sea included grains, furs, horses, oils, cloth, wine and people. For Europeans, the Black Sea provided access to a branch of the Silk Road and the importation of silk, satin, musk, perfumes, spices and jewels. It is possible that Marco Polo was traveling this route when some of these ships sank around the 13th century.
Two other important elements of the MAP project are Education and Documentary. Eight students of school age were selected to join the science team on board in order to experience and even participate in many of the procedures. The documenting of this entire project is placed in the capable hands of Black Sea Films. Just as the science involved in this MAP project is cutting-edge, so is its filming, for the Black Sea Films team includes those who created the award-winning BBC series Blue Planet and Planet Earth.
The MAP findings of these ancient shipwrecks from the Byzantine and Ottoman Eras is the most significant underwater archeological discovery of this century and demonstrates how effective partnerships between academia and industry can be, especially when funded by enlightened bodies such as EEF.
AquaSur regularly makes a splash in the aquaculture world at its semiannual conferences. It's the most distinguished gathering of its kind in the Southern hemisphere, with major players in the field attending. In October 2016, Aquabotix CEO Durval Tavares traveled to Chile to take part in the AquaSur 2016 conference, which explored the present and future of ROVs in aquaculture and more. Over its four days, the conference accommodated 22,400 visitors representing 42 countries. Attendees included representatives from other ROV companies, food producers, medical companies, and chemical companies. By the end of the conference, there was widespread recognition that robotics was the wave of the future for keeping fish healthy and ensuring the livelihood of those in the aquaculture business.
Puerto Montt, Chile, hosted the event. Chile employs 80,000 people in its aquaculture industry, and is currently looking to expand the industry along the country’s northern coast. To encourage growth and safety in the aquaculture sector, pending legislation will likely encourage the use of ROVs to protect the environment. Using ROVs is a safer way to look underwater, especially inside nets, for problems that could affect the fish and nets. With the potential grown of ROV use in Chile and other countries with aquaculture industries, Aquabotix and its Chilean distributor TekChile, had an interested audience for showcasing various products from the Aquabotix line.
Outside the conference, separate events featured demonstrations of the ROVs from Aquabotix. These demonstrations greatly impressed those who saw substantial benefits over currently offered technology. The main advantages for farm operations of these products included the stability of the Endura and maneuverability. Thruster power was especially intriguing for the operators because it was unlike anything they'd seen. The Endura can be configured specifically for aquaculture with five standard thrusters, side thrusters, and a high output option. These attributes of Aquabotix's ROVs mean that these devices, and other ROVs like them, are predicted to not only be a perfect fit for the future of aquaculture but also a necessity as demand increases for fish and other water-grown products. Operators can use the extra thrusting power so the vehicle can be used in high currents compared to their current products.
The conference was a good time to illustrate the innovations represented by products such as the AquaLens Connect. Attendees at the conference discussed ways to reduce waste and cost, and underwater monitoring with the AquaLens Connect is a clear solution to these issues. The future of aquaculture will rely more on remote monitoring of nets and facilities as the industry expands. With remote monitoring, several sites can be watched at once, from a single screen, reducing the necessity for needing multiple people to watch several locations at once. The AquaLens Connect allows up to 32 cameras to be connected in a network for simultaneous viewing, and because the cameras are not static, a wider field of view is available to each camera. With pan and tilt of 120 degrees in each direction, a single camera can show a wide range of underwater space. When coupled with the unique abilities of an ROV, such as Endura's fish plow that removes dead fish, these devices make operations more profitable and safer for the employees and the fish.
The future of aquaculture is now, and ROVs and underwater cameras are on the forefront of the technology farm operators need to progress. By keeping up with the changing industry, and participating in exciting events like AquaSur 2016, Aquabotix will help our customers stay on the forefront of the evolving technical landscape.
Aquaculture and fisheries are a major source of the world’s protein production, and while fisheries are stagnating somewhat due to overconsumption, aquaculture production is growing at tremendous rates. As aquaculture facilities fill in the most desirable coastal locations, it is a certainty that future growth will take place in deeper water, where use of human labor will be more expensive and much more dangerous. One major job that will require significant automation in order to be economically practical is monitoring the aquaculture facility.
Aquaculture facilities require careful monitoring of a number of important parameters. The environment itself needs to be monitored for water quality, temperature, current, and so forth. Operators also need to be able to inspect hardware such as nets and cages, to count fish in particular enclosures, to locate dead fish, to check nutrient levels, to measure fish stress levels, and more. All of this information gathering is often done by human labor at onshore or shallow-water facilities, but that is impractical when the aquaculture facility is far offshore. Operators can’t hire from the local community when the local community is underwater – they have to use automated remote monitoring technology. Even in facilities where human labor is available, the cost and liability requirements of human workers will make automated remote monitoring a useful adjunct.
A number of different types of remote sensor can be used to monitor aquaculture operations, but one of the most generally useful instruments is also one of the simplest: a video camera. High-definition video cameras can capture a wide range of data both above the water and beneath the surface. Advances in robot vision, that is, the ability of computers to understand and utilize video feeds, mean that a huge number of video camera feeds can be interpreted by computerized systems. The aquaculture base can monitor types and numbers of fish in an area, examine nets and gates for damage, scan the bottom underneath fixed pens to check contamination levels, and even assess the weather pattern. AquaLens Connect, the underwater camera system from Aquabotix, has been built to withstand and excel in these challenging conditions. It features a full 1080p HD video with live view, push button recording, pan and tilt.
Aquaculture requires a great deal of management and assessment to be effective and profitable. Feed levels have to be continually adjusted to prevent excessive buildup of nutrients in the wastewater, fish populations have to be counted and their health checked, incursions from predators have to be seen to be mitigated, and physical infrastructure, always susceptible to storm damage, has to be kept in trim through regular inspection and maintenance. All of these tasks require that the aquaculture operator be aware of the condition of the facility. Stationary video cameras, as well as ROV-based roving cameras, provide a cost-effective means of achieving this goal.
There’s just something about robots.
Kids today grew up with robots represented in half the TV shows, books, and movies they were exposed to. The older generation remembers a childhood of R2-D2 and C3P0 – and their parents, in turn, remember Robbie the Robot, Klaatu, and other spectacular pulp-era automatons. Robots immediately seize the attention and fire the imagination of children in a way no other technology can.
We recently attended the Southcoast MA Mini Makers Faire, held near our Massachusetts headquarters, and saw first-hand how blazingly excited kids got with exposure to robots. Fortunately, the beneficial influence of studying robotics goes way beyond maker’s fairs and trade shows. Robotics may, in fact, be the key to inspiring the next generation of STEM (science, technology, engineering, and math) researchers, workers, and entrepreneurs.
There is a developing crisis in the STEM field. Employment analysts expect that by 2018 there will be 2.4 million unfilled STEM jobs in the United States alone – and new STEM jobs are desperately needed. In fact, STEM fields will grow almost twice as fast as conventional areas of employment in this decade. Higher education is doing its part, but the fact is that inspiring young kids to go into STEM fields is the key to ensuring that the American workforce is up to the challenge of dealing with a high-tech economy.
And that may well be where the robots come in. Research shows that engagement with STEM concepts in early childhood and elementary school is practical – the kids can grasp the ideas – and effective. Specifically, out-of-school activities that engage the attention of young kids are very likely to create a lifelong pattern of seeking new knowledge and activity in those same fields. Kids who do something educational *as a hobby on their own time* are clearly hooked. Robotics, as it happens, is an area where even very young kids can do meaningful work, and they will fight to get at the materials and lessons they need to do it.
One area of strong fit between robots and early childhood education is that the elementary school period is a time when kids are having to learn reading and abstract symbol manipulation skills – critical skills to have, obviously – but what they really want to do is to be hands-on, kinetic, to draw and to shape and to create physical objects. Working with robots encourages both the abstract skills that they need (but often aren’t terribly excited by) and expressing those skills with hands-on tinkering and mechanical work. Most of the math and science education in the lower grades is entirely theoretical – robotics allows kids to put what they are learning to direct, immediate application.
Fortunately, the robotics industry is well aware of how critically important it is to get the youngest new learners excited about robots. There is a vast wealth of resources available to schools and educational programs for designing, creating, and deploying robotics projects. Many of these programs are cast as competitions, such as the Wonder League Robotics Competition, where kids from 6 to 12 can compete in a series of events by sending in videos of their robots successfully completing a series of challenges. The Wonder League events focus on programming. The Vex IQ Challenge, for elementary and middle schoolers, focuses more on robot operations, while the First Lego League Jr., for kids age 6 to 10, is naturally all about the building. There are many other programs and events in a similar vein.
Class time in schools is, of course, a natural incubation point for STEM education, and robotics works well as the framework in which to teach a wide variety of STEM concepts. Teachers report that teaching robotics requires kids to look at complex systems made up of multiple parts, to design and connect those systems themselves, which teaches real-world problem solving. The kids are, of course, highly motivated because they are learning by doing, rather than by listening to a teacher talk. And kids who learn best on their own can do so even outside of the school environment with consumer systems like Lego MindStorms, a fully-functioning robotic development kit using Lego blocks for implementation.
No single concept is going to be a magic bullet that solves our shortage of STEM workers. It will take a lot of different ideas, and a lot of different initiatives, to get to where we need to be. It’s clear, though, that robotics is an area with vast potential to inspire young minds to innovate and design the world of the future.
There have been several news stories recently about challenges with Lithium Ion batteries. Most notable is the situation with the Samsung Galaxy 7 but issues with airplanes, hover boards and other personal electronics have been in the headlines.
Since their introduction in the early 1990s, Lithium Ion batteries have become the standard for consumer electronics devices, including smartphones, smartwatches, laptops and cameras. Aquabotix utilizes Lithium Ion batteries to power our ROVs because of their performance and has found them to be very reliable, stable and safe. We have experienced no reports of any problems with these batteries from our customers.
Most Aquabotix ROVs have only internal batteries. That is, the only way to charge the batteries is while they are inside the vehicle and charged through the topside box or vehicle charging port. When charging the batteries inside your vehicle, the danger of fire caused by the overhearing or other failure is minimal. Still it is prudent to charge the batteries only until they are fully charged (charger LED light changes from red to green) and then to unplug the charger from the electric power source.
Some commercial ROV users have purchased additional batteries and external battery chargers from Aquabotix. If you have extra batteries and external chargers, please follow these precautionary steps.
- Always make certain that the batteries, connectors, charger and all other parts are clean and dry.
- Make certain that the batteries and charger are paired as they were supplied to you. Do not mix batteries from one vehicle with another. Do not use any charger other than the one supplied with your vehicle.
- When externally charging batteries, it is advised that the batteries be contained in a fire retardant or fireproof safety bag designed specifically for this purpose. These can be purchased inexpensively or, if you purchased extra batteries and an external charger from Aquabotix, we will be happy to send you a safety bag at no charge. Please contact Aquabotix Customer Service with your vehicle serial number.
If you will be traveling by air with your ROV batteries, please contact Aquabotix Customer Service for further instructions.
Aquabotix is committed to the satisfaction and safety of our customers and users. We appreciate your support and are happy to answer any questions you may have.
Phone: +1 508 676 1000
Many ROV applications require that the operator know the position of the ROV with varying degrees of precision. However, precise navigation for small ROVs is actually a very difficult task to achieve.
There are three basic positioning techniques that are practical for use on ROVs: dead reckoning, Global Positioning System (GPS), and Ultra-Short Baseline (USBL). We will look at each of them in turn.
Dead reckoning is the navigational method used by mariners all over the globe before the invention of compasses, chronometers and sextants. In dead reckoning, the navigator starts with a known (or estimated) position, and from there attempts to gauge the vehicle’s position by applying the vehicle’s heading and speed. Depending on the tools available, dead reckoning can be a surprisingly effective form of navigation. In the modern era, where the starting position of an ROV may be known with great precision and the heading and speed of the vehicle are also known quantities, dead reckoning can be sufficient for many applications. However, dead reckoning has one fatal defect: it cannot account for currents in the water. If the current is significant, the position of the ROV at the end of a run can be vastly different than the reckoned position.
The widespread availability and accuracy of global positioning systems (GPS) has made terrestrial navigation a breeze for motorists and surface vessels. Anyone with a line of sight to four or more GPS satellites – which effectively means anyone on the surface of the Earth – can use an inexpensive computerized navigation device to locate themselves, with an accuracy of as close as ten feet. GPS is cheap, effective, and nearly foolproof – so it’s the perfect solution for ROV navigation, right? Unfortunately, no – GPS is almost useless for most ROV applications. The problem is that the satellite communication signal is severely blocked by fresh water, and totally blocked by sea water. Underwater vehicles cannot use GPS without coming to the surface. There are some specialized use cases for GPS on an ROV, but they are few.
Ultra-Short Baseline (USBL) is a technique for determining a vehicle’s position underwater. It is a fairly complex system which involves a base station/transceiver, usually mounted on a ship, a transponder/transceiver mounted on the ROV, and a sophisticated computer system (usually located with the base station). The base station sends out a powerful acoustic pulse, similar to a sonar “ping”. This pulse is picked up by the transponder on the ROV, and a response pulse is sent from the ROV back to the base station. When the base station receives the response pulse, it calculates the duration between the initial signal and the response, and determines the range between the two transceivers based on that time. A set of transducers in the transceivers permits the calculation of a bearing between the two transceivers; the combination of the range and the bearing gives a precise position for the ROV relative to the base station.
USBL is extremely effective and accurate, but it is also expensive - a USBL installation for an ROV can cost upwards of $20,000. It also has a technical weakness in that under “busy” sonar conditions – a crowded harbor, for example – can cause problems for the system. However, for now, USBL represents the state of the art in ROV navigation systems.
Depending on which maritime body you ask, there are somewhere between 50,000 and 100,000 large ships sailing the world’s oceans, with cargo vessels, passenger ships, and warships making up the bulk of this number. Commercial vessels are required to have their hulls inspected on an annual basis, and military vessels generally follow a similar inspection regimen. There are various global and national bodies which provide certification standards, such as ABS (American Bureau of Shipping) and Lloyds of London. The goal of inspecting large vessels is to protect the owners of the ships, the crews, the passengers, the companies using the ships, and the insurance industry.
There are a variety of different certification standards, but the standard ABS inspection regimen is fairly typical for the industry. The ABS regimen is known as HIMP, which stands for Hull Inspection and Maintenance Program. HIMP has a three-tiered system of inspections, with annual inspections, three-year inspections, and five-year inspections. The three- and five-year inspection tiers encompass all the inspection areas of the lower tiers, while adding further areas of the ship to the inspection list. HIMP inspections cover the entire vessel, but the underwater portion of the survey is the trickiest for ship owners. Underwater surveys can be conducted by human divers, but increasingly this job is being handled by remote-operated vehicles (ROVs).
On a commercial vessel, the diver or ROV must provide visual data on the stern and rudder bearings, the sea suctions and sea valves, the propellers, and – most time-consuming - the hull plating. The inspection must look at any markings on the hull, all inlets and discharges, the rudder, the propeller, and all other objects that protrude from the hull. Corroded or damaged areas must be examined closely, and although thickness testing is not automatically part of the HIMP, any area found to be damaged or corroded is likely to be examined internally and have the thickness tested at the affected spot(s).
Military vessels follow a similar inspection regimen, and many military vessels will also have stencil-marked areas of the hull which need to be looked at. Inspections will check the hull and other secondary areas of the vessel for biofouling, to assess the need for having the ship’s bottom scraped. Inspections generally involve several waterline-to-waterline underwater traversals of the vessel, following the seams of welded sections. Propellers need to be inspected on both their front and rear facings.
In the early years of ROVs, their use in underwater hull inspections was relatively rare because the low video quality of early vehicles made their results of marginal utility to inspectors. Today however, with true HD displays and cameras on even consumer-level ROVs, these useful vehicles are an integral tool for large hull inspections. Since inspection divers need to be ABS-certified, many surveying companies are finding that it is highly useful to conduct a pre-inspection using an ROV only. This pre-inspection can find any problems that already exist so that they can be mitigated before the actual inspection, preventing a time-consuming, and expensive, temporary suspension of the vehicle’s certification when the inspector finds significant problems.