One of the most common reasons for divers or ROVs to go into the water is to search for something. The “something” can be enormously variable – an engine that fell off a boat, a weapon, a human body, a sunken ship, an automobile – but regardless of the type of object being searched for, there are some common search patterns that are worth knowing about.
The arc search, also known as a half-moon or semi-circular search, is a very simple and effective search pattern frequently employed by divers looking for large objects (such as automobiles) or working on non-flat bottoms. In the arc search pattern, the diver works at one end of a taut tether, while a stationary handler holds the other end of the tether. The handler establishes visual or other landmarks on each end of the arc, and the diver moves along the arc, keeping the tether taut so as to maintain the proper distance.
When the diver reaches one end of the arc, the handler reels the tether in by a distance determined by the nature of the search. In general, the larger the object being searched for, the larger a distance the diver will be reeled in. Then the diver proceeds back along the arc at the new, shorter, distance, and the process repeats itself until the entire area of the arc has been covered.
Arc searches are fast, but have a couple of downsides. Although they work well even in scenarios where the bottom changes contour dramatically, this means the diver has to continually equalize their pressure. In addition, if there is a lot of bottom growth (such as weeds), the tether will tend to accumulate that growth quickly and this can put a lot of weight on the line, creating an entanglement hazard for any divers in the area.
Arc searches employing ROVs alone can be very practical. Since the ROV already has a tether, the operator can simply lock the tether length in place in order to perform each leg of the arc search, then reel in tether to set the distance for the next leg. ROVs can also augment a human-performed arc search by following the same pattern and employing sonar in addition to the diver’s visual search.
A circular search pattern can be used by one diver, but can use any number of divers, making it a popular choice when searching very large areas. In a circular search pattern, an anchor marker is dropped at the center of the search. A tether is attached to the anchor, and one or more divers take up stations along the tether at predetermined distances. Each diver marks their starting position so that the team will know when a complete circuit has been made. The divers then swim a complete circle, keeping the line taut. When a complete circuit is made, the divers move to new positions along the line, and the process is repeated. When the line length starts to make the search impractical, a new center point can be chosen and a new search initiated.
The disadvantages of a full circular search are that the search is not very tolerant of bottom variations, since all the divers need to be on the same line. If multiple searches must be done over a wide area, of necessity there will be considerable overlap between the searches, hindering efficiency. In addition, if a large area is being searched, the divers on the outer portion of the search will have to move faster than the divers on the inner portion, which can result in a hasty search that does not thoroughly cover the target area.
ROVs can be used in a circular search pattern to replace or augment human divers, just as on an arc search.
A compass search is a search which relies on the use of underwater compasses rather than search lines for navigation. A compass search may be needed in an area of rough terrain where a line would quickly become entangled, or in visibility conditions so poor that orienting to the line may be difficult or impossible. In a compass search, divers use wrist compasses or inertial navigation devices to maintain proper orientation.
A common type of compass search is the spiral box. In the spiral box search, a diver starts at the estimated position of the target, and then swims in a cardinal direction for a distance about as far as he or she can see under current conditions, counting the number of kicks it takes to cover that distance. The diver then turns 90 degrees, using the compass to set the bearing, either clockwise or anticlockwise depending on the layout of the area, and takes the same number of kicks before turning (in the same direction as before) and then swimming for twice that number of kicks.
For example, if the number of kicks is 10, the diver might kick 10 times, turn clockwise, kick 10 times, turn clockwise, kick 20 times, turn clockwise, kick 20 times, turn clockwise, kick 30 times, and so on. In this way an expanding box is searched, with the compass being used to ensure that the diver is actually covering the correct area. ROVs can make an outstanding contribution to this type of search, since their positioning sensors are more reliable than a diver using a compass; using an ROV to handle the navigation elements of this type of search can free the diver to devote 100% of his or her attention to the actual search.
The jackstay search, also known as a jackleg search or a Z-search, is a very powerful search pattern that is almost guaranteed to find even small target objects, if they are within the search area. It can be used by one or two divers at a time, and it works well in areas where there is either a flat bottom or a consistent slope, such as an embankment. In a jackstay search, two weighted anchors are placed at opposite ends of the search area, with a line taut between them. The diver proceeds along the line, searching along the path. When the diver reaches the terminal anchor, he or she moves the anchor by a short distance, between 60 and 80 percent of the visibility range, in the direction of the search progression. The diver then moves back along the line, covering some new ground and a lot of old ground. When they reach the other terminal, they repeat the process, so that the search line is moved a few feet at a time through the entire search zone. A second diver can follow the first, providing additional coverage.
The disadvantage of the jackstay search is that it is slow and labor-intensive. An ROV can make a major contribution to the efficiency of a jackstay search by filling the role of the backup diver, following the human diver through the pattern and providing both a second set of eyes and a sonar backstop to the visual search.
There are literally dozens of common search patterns, many with specialized applications for certain conditions, and we have only discussed a few of the most commonly used patterns here. However, ROVs can make an excellent addition to almost any search pattern, whether to directly search, to provide navigation and orientation support for human divers, or to conduct preliminary assessments of search areas without risking human divers in dangerous waters.
There are many individuals, organizations, and businesses that would get a lot out of owning an Aquabotix remote-operated vehicle (ROV), but who may shy away from the initial purchase. To help those individuals and organizations “test-drive” an ROV at their convenience, Aquabotix has rolled out an ROV rental program. With the rental program, ROV customers can get first-hand experience with a full-featured ROV in their own environment at a reasonable cost. This “try before you buy” program allows your operation to test how you would use an ROV in your daily business without having to jump into the deep end right away.
Renting an ROV is flexible and easy to do. Rentals are offered in blocks of two weeks at a time; you can rent for two weeks, a month, six weeks, or longer, depending on your individual needs. Aquabotix rents both sport and professional model, so there is a rental that’s right for your application no matter what it may be. Upon completion of the rental agreement, your ROV is shipped directly to your door by UPS or Fedex, so you can get right into the water.
You can use your ROV as though it were your own – you can inspect ships and underwater objects, maneuver around your water tanks, or use it to support commercial dives. As long as you return the ROV in good condition, you may use it freely for the duration of your rental. In addition, should you choose to purchase an Aquabotix ROV at the conclusion of the rental term, then fully 75% of your rental fees will be applied towards your ROV purchase.
Learning to use your rented ROV is extremely simple – in fact, Aquabotix ROVs are among the easiest to learn to “fly”. Absolute novices can be maneuvering their ROV in three hours, and can be a proficient operator not long after that. Aquabotix ROVs can be controlled either using an iPad or a game controller. You will have no difficulty in becoming a skillful ROV operator not long into your rental term. There are manuals for the ROV and the control software online. In addition, there is a great tutorial video covering the HydroView control software at https://www.youtube.com/watch?v=IKTGFkGZLdY.
Renting an ROV is a great low-risk way to explore these innovative and useful vehicles without committing tens of thousands of dollars to an unfamiliar hardware platform. By renting an Aquabotix ROV, you can find out how an ROV can expand your existing operation, enhance your underwater capabilities, or create new opportunities for your business or organization. Aquabotix makes renting easy with a straightforward rental agreement, convenient short rental terms, and a family of ROVs with a gentle learning curve and great user support. The water is starting to warm up – this is a great time to start getting your feet wet in the world of ROVs.
In the post-9/11 era, the security of sea and river ports became an issue of great and pressing public
concern. Thanks to the efforts of multiple layers of government and private security, no major terrorist
attacks at US ports have occurred since that dark day. However, port security remains a critical area for national and local law enforcement, and it is an area where remote operated vehicles (ROVs) such as the Endura 100 SLE can make major contributions.
There are 360 commercial sea and river ports in the United States alone, and those ports handle
approximately one-fifth of the global maritime trade. These ports handle more than 70,000 large ships
(and an innumerable plethora of smaller craft) annually, carrying more than two billion tons of cargo in
and out of the United States. Securing and ensuring the safety of that much traffic is a job of stupendous
ROVs can help with this task in a number of important ways.
The underwater physical infrastructure of the port itself, as well as the submerged hulls of vessels using
the port, are key areas for port security concerns. However, visual inspection of these zones is often
problematic. Ports are highly-trafficked areas, which creates safety concerns for human divers. In
addition, the visibility conditions beneath ships and around piers are often exceptionally poor. Silt
movement from tidal flows and bottom stirring from vehicle traffic can make it almost impossible for a
human diver to see.
ROVs like the Endura 100 SLE ROV can be equipped with 360-degree scanning sonar, allowing the
ROV to see things where a human diver would be helpless. In addition, ROVs can engage in much longer
dives than humans. This allows exhaustive search scenarios that would be extremely expensive if human
divers were deployed.
In situations where visibility is better, the Endura 100 SLE has the ability to record 1080p
high-quality video. This permits the ROV to be deployed as an eyes-on monitoring station at a fixed
point or along a patrol route for hours at a time, again far exceeding the capabilities of a human diver.
Underwater surveillance and monitoring missions are thus made much more practical and affordable.
Vehicle hull inspections are an area where the positioning capabilities of Aquabotix ROVs can provide a
unique edge. Most hull inspections do not attempt exhaustive coverage of the entire hull area, because
this is impractical and would take too long – instead, inspections focus on a number of fixed high-value
points of interest. The Endura 100 SLE has advanced positioning software which makes programming
a search of these known points practical and straightforward.
ROVs are capable of carrying out advanced port security missions even without being controlled by
highly-paid professionals. Anyone can learn the basics of “flying” a Endura 100 SLE in just a few hours
of practice, and mastery takes only a few days. In addition, the low weight and easy handling
characteristics of the Endura 100 SLE mean that a single operator can carry the unit to the point of
launch, control it throughout the mission, and retrieve it single-handedly, keeping costs to the bare
Port security workers can control the Endura 100 SLE through a simple and intuitive iPad application,
or using a wireless handheld controller. In addition, the video and sonar data produced by the ROV is
stored on-board – no additional recording devices are required. Date and time stamps on the media
make the use of ROV-acquired data easy to document for law enforcement purposes.
Perhaps the most critical contribution an ROV can make to port security efforts comes from the fact
that, in the worst-case scenario, the ROV is expendable in a way that a human diver never will be. Port
security often involves investigating strange objects, which could easily be explosive devices or even
worse. An investigation of such an underwater device using human divers is risky at best and may have a
tragic outcome. ROVs can fearlessly investigate such threats with the worst-case scenario being merely
the loss of some metal and plastic. This allows port security to aggressively investigate suspicious objects
in a way that simply can’t happen relying on human divers alone.
Port security will never be an easy task, and the problems facing port security forces are likely to grow along with the volume of business done at the port. Every new problem inspires the creation of new tools, however. ROVs like the Aquabotix Endura 100 SLE can expand the ability of port security forces to keep their facilities and visitors safe, at a reasonable cost.
There is a story – probably apocryphal – that one of the early Roman emperors was approached by an inventor who had created a steam-powered device for moving huge marble columns around, an invention of obvious interest to the monument-building Romans. The emperor rewarded the man for his innovation, but declined to purchase the device for the empire, stating that he had a city full of workmen who needed to eat, and the invention would put them all out of work. In the modern era, most of us recognize that the addition of powered machinery doesn’t permanently take jobs away from workers; rather, it changes the nature of their work, usually for the better. Today’s construction machine operators make a lot more money and work a lot more safely than did the burly gangs of workmen in Roman times.
In many ways, we’re smarter than our Roman forerunners. Today we are a lot more likely to see opportunity in new technology, not threats. Commercial divers sometimes worry about ROVs undercutting them on price for some kinds of jobs, but the opportunities for new business provided by ROVs are a much larger vein of possible work. ROVs represent an affordable way for divers to expand their businesses by increasing the human diver’s capabilities while simultaneously cutting costs and improving safety. ROVs are not going to replace human divers – instead, they are going to add to those divers’ ability to work productively underwater.
Diving is difficult and often dangerous work. It’s uncommon for a client to need a diver to conduct a brief excursion in crystal-clear waters in order to do some trivial task. Rather, divers are asked to handle hard jobs in unpleasant and sometimes unsafe conditions. Many times, a job can’t be done because there’s no way to do it safely. ROVs can change that, because an ROV worth a few thousand dollars can be risked in many situations where a human life would be at too much risk. That ability to run additional risks with only hardware on the line can actually improve the ability of a dive team to take on a job, because the ROV can scout the work and establish whether or not it actually is a human-achievable job.
Many diving jobs involve a great deal of reconnaissance and scouting in order to do an hour’s worth of actual work. For example, in a salvage operation, a diver may spend days looking around a site and finding the items that are worth retrieving, then do the actual salvage work in an afternoon. However, all of that scouting time is just as expensive, just as dangerous, and just as exhausting as the actual paying work at the end. An ROV doesn’t require a trained commercial diver for its operation; the diver can hire support personnel (who work a lot cheaper) to do the scout work with a controlled ROV, then go into the water herself later on when the job is narrowed down. Same payday, but a lot less cost upfront – plus the diver can work more actual jobs.
Some jobs which require a human diver can actually be done under a diver’s direction but without the diver having to go into the water, or at least not having to go in as much. For example, hull inspections or damage surveys often involve putting eyes on the target, but don’t require any hands-on work. A diver reviewing an ROVs video feed can do just as good a job as if they had been in the water the entire time – but again, with much lower costs and no risk. Remember, risk costs money – in insurance premiums, in medical expenses, in training costs – and reducing risk is effectively the same as putting money back in your pocket.
Even hands-on work like underwater repair can be made more efficient and less stressful with intelligent use of ROVs. ROVs can be used to survey the worksite and get good information into the dive planner’s hands before anyone puts a foot in the water. And while the divers are actually working in the water, other staff can use ROVs to keep eyes on other areas of the work site, or to fetch tools and parts without a lengthy surfacing process. We profit and grow when we see the potentials unlocked by technological change.
Divers who adapt to the technological innovation coming to the industry by adopting the new tools that ROV technology is making available are going to be able to do more work, to do it better, and to do it safer than they were doing it before. Adding ROVs to an existing dive business requires challenging some ideas about how the business should run, but it’s a change that will pay off.