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ARTICLES FROM BACK ISSUES OF UNDERWATER MAGAZINE 
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The petroleum industry's entry into deepwater, coupled with an increase in
romantic search and salvage missions for high-profile quarry like Titanic,
is pushing the technological envelope of the underwater vehicle industry.
Increased technology comes with a high price tag. However, there is an
interesting underground movement of sorts taking shape, do-it-yourselfers
who have designed and built their own underwater vehicles, often at a
fraction of the cost of what the "big boys" offer. By Daron Jones
The design and operation of underwater vehicles is big business. And despite the most recent crisis surrounding worldwide oil prices, the oil and gas industry is still a multi-billion dollar entity. To this point, subsea work performed by underwater vehicles has played a significant role in helping the petroleum industry stretch its realm of productivity beyond the continental shelf. As we enter the new millennium and the new deepwater era, remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) will only become more significant in the chase for oil and gas profitability. The vehicles and their tooling packages will be asked to do more, will therefore be more technologically advanced (see "UnderWater Marketplace: ROV Tooling" on p. 35 of this issue), and consequently, more expensive. However, the essential components that make an underwater vehicle actually work remain the same, and can be assembled in a relatively inexpensive and simple manner. In fact, enterprising souls everywhere have built their own budget underwater vehicles. Several of these entrepreneurial types are featured here. Whether these backyard projects were spurred by commercial need, school projects, or were just for fun, they demonstrate that, even in today's technological age, the common man can design and build a working underwater vehicle with off-the-shelf components available just about everywhere. In fact, Dan Fjellroth's established website, www.ROV.net, hosts an annual design-and-build competition just for the do-it-yourselfers. There are three classifications of commercial ROVs: low cost ROVs (LCROVs) which can be as simple as tethered underwater cameras and are primarily used by inland contractors, mid-sized ROVs which are used inland and offshore, and work class ROVs that do most of the offshore work. These various vehicles range in price from $20,000 to several million. The homemade underwater vehicles built by the following handymen range between $5,000 and $100,000, so there is something for everyone.
Jeff Byars - the Corps' secret weapon The ROV is a system of tubes equipped with three propellers, two lights, and a video camera mounted to the frame. It is controlled from a surface boat via cables. A VCR and monitor on the boat shows and records what the camera sees underwater. Byars conceived the idea a few years ago while attending the Corps' Diving Supervisory School in Key West, Fla. "The safety manual says if you can do underwater repairs without divers, it is safer," said Byars. So he thought of using an ROV to inspect lock and dam structures and videotape them. Structural engineers can then review the tape and see what repairs are needed. Byars, captain of the survey boat E.B. Wallace, is a tinkerer. "My grandfather was a farm equipment mechanic, and when I was about 10 years old I worked with him and learned a lot," he said. "I've been in the diving business since 1982 and I've always been interested in ROVs. And I used to be a commercial diver, so I have an understanding of what you need to see." To most people, ROVs are the high-tech megabuck probes that explored the Titanic and Bismarck wrecks. You wouldn't imagine one could be built by a handyman in his garage. But Byars built an ROV on his own time and expense in 1992. That prototype cost about $5,000. In 1993 he tested it at Corps locks and dams. Once Byars proved the prototype, managers on the Tenn-Tom Waterway and Black Warrior-Tombigbee (BWT) River System projects funded a new $8,000 ROV. Byars built both ROVs using off-the-shelf materials - PVC pipe, trolling motors, lights, and a video camera. The current unit weighs about 75 pounds and runs off a 12-volt battery. The ROV uses five or six batteries for each inspection. The surface boat carries the batteries and feeds power to the ROV via waterproof cable. "Each time we used it at Bay Springs we saved about $23,000 a day that would be spent on divers," Byars said. "It can pay for itself very quickly." In 1994-95 Byars used his prototype to inspect structures during the Bay Springs Lock closure. Then came 15 inspections for the Tuscaloosa office on the BWT. In May 1997, Byars' team did the first inspection with the current ROV. Since then they have done eight more. "We've had good success so far," Byars said. "Some people thought you wouldn't be able to see anything underwater," but the lights give a clearer picture than the naked eye. The ROV can't replace divers for everything. But even when divers have to go down, the ROV can still act as a safety scout. At Miller's Ferry, below the spillway, the ROV spotted a log with giant hooks all over it and warned the divers of the hazard before they entered the water. Each situation where the ROV is used is different. "You just have to adapt and change things as you go to fit different tasks," he said. Byars is already planning the next ROV modification - attaching a mechanical arm to the ROV. He is also designing a third generation ROV. This one will have two controllable arms for lifting and moving. "I've got the frame built on a new model." The ROV is a challenge, but it fascinates Byars. "It's a work in progress," he said. "You have to adapt it to different jobs. A lot of it is experimental. We do everything as safely as possible, and using the ROV is a lot safer than putting in divers. You just have to adapt it to fit different tasks. We're learning as we go." (Exerpt by Tim Dugan. Reprinted by permission from the February 1999 issue of Engineer Update, copyright 1999 by the U.S. Army Corps of Engineers.)
David Thompson Thompson had some trouble locating a controlled test area. "No one would allow me to put my machine in their swimming pool for fear of contamination," he says. "Most of my tests were done in Morro Bay on the central Californian coast. Unfortunately, the water was very murky and not much could be seen. The other systems worked, but the maneuvering system was a bit under powered. I had designed a system utilizing water reaction jets which had some trouble maneuvering the craft in the currents. I plan on modifying the system to be more powerful." Thompson used readily available materials from hardware stores and equipment supply companies like McMaster Carr. Most of the ROV housing is built with PVC and ABS parts. The electronics are basic components purchased mainly from Radio Shack. Thompson used a lathe, mill, and other common tools to modify the parts to make them work and fit together properly. "There was very little information about ROVs and their designs so I had to start from scratch," he says. "I first listed the functions I wanted it to perform. I then researched different ways that these functions could be accomplished and what materials were available to me at relatively low cost. I wanted to try out some unique ideas that I had not seen before. For example, I wanted to use a maneuvering system using water reaction jets as opposed to motor driven thrusters. I then designed the entire system, including detailed calculations on every component including weight, buoyancy forces, stress, and fluid flow. With these calculations I knew how the ROV would perform before building it. For example, by calculating the weight and displacement of the ROV, I could design a neutrally buoyant craft." The design was successful and Thompson went on to win the 1999 ROV.net Design and Build Contest. He plans to build another vehicle in the future, using what he learned the first time around.
Gavin Chait's designer ROV An electrical engineering student at the University of Cape Town, Chait originally developed an interest in ROVs when he attempted to design a controller for a colleague's miniature ROV as part of his undergraduate thesis. "But that was going to prove impossible," says Chait. "I've discovered that, especially in South Africa, everyone - and I mean everyone - seems to think that project and business planning is for mere mortals. So we'll just slap something together, spend a great deal of money, and then act all surprised when it doesn't work. I managed to get my terms of reference changed to creating a design specification instead of simply designing a controller for an ROV that some of the experts I'd spoken to didn't think would work. The more I learned about ROVs, the happier I became at my foresight at not getting too closely involved with the original ROV." Chait stresses that, although he believes strongly that his design will work, he does not consider himself an engineer. "I have a very practical common sense bent and don't worry too much about the details. A good trait in a project co-ordinator, a bad trait in an engineer," he says with self-effacing humor. "It took a great deal of time to understand ROVs," he says. "They're not difficult to understand from the outside, and once I understood the secret, they're not hard on the inside either. The real problem is that just about everything is proprietary and based on designs from the 1960s, or even older. New technology is just bolted onto the side and control systems are fairly rudimentary, requiring the pilots to be highly skilled." Chait began to research ROV design, but found it difficult at the outset. "The difficult part was realizing how little help I was going to get, and then how small the industry is. Word got out about what I was up to. The only chap in Cape Town who acts as the agent for most of the equipment was inundated with calls to find out what I was up to. We eventually met and he was extremely helpful." Chait was ready to begin an actual ROV design from scratch, starting with the obvious questions: How does one build an ROV? What is it actually supposed to do? "Looking at the basic designs, I couldn't understand why they were all so analog. Whenever computers were used, they merely patched into a massive mess of analogue equipment. It looked like a machine designed by committee. I was hooked." Chait was convinced he could not only produce a better design, but that it could be executed using entirely off-the-shelf components. Finding the components and deciding how to put them together became the task. The design went through various stages as Chait learned the ropes. "Silly things like realizing that a digital voltage signal sent down 300 meters of cable will be invisible at the other end and then finding out what the components are for a voltage to current converter and realizing that it's not as hard as I thought." The control algorithms were the trickiest part of the design. Chait had to discover what sort of feedback loop was required to get the ROV to hover, what measurement devices were needed, etc. "The trick here is to get the ROV to act like the machines in video games and controllable with a single joystick," he says. "The other tricky bit was positioning the thing accurately. A GPS doesn't work through several hundred meters of water. So we do this, an altimeter and integrate the dx, dy, dz from the movement sensor. Zero the ROV at the GPS at the surface. Work out the length of cable and its likely curvature, plus the ROV's net direction. Calculate and you're pretty close." At this point, Chait knew where it was and what it was doing underwater, thus making it easier to control. The computer controller would allow the operator to preprogram a route and send the vehicle on its way. "I used distance pingers to pick up a distance from object in all six degrees which would allow it to keep out of trouble. You could use some image recognition software to boost the picture quality and use it to pick up hull damage, metal fatigue, and so on." One very interesting element of Chait's design was the idea of using a virtual reality helmet as the controller. He envisioned wiring the sensors in the helmet to the camera motor so that when the pilot turned his head, the camera would also turn. It took Chait about four months to complete his design. "The components specified are totally off the shelf, but the front-end software still has to be written," he says. "Anyone with a basic interest and understanding of ROVs should be able to handle the plans. Off the shelf components basically assume that one played with Lego as a kid." Plans are available at http://www.angelfire.com/ct/gchait/rov.html.
A student project Louis Cranek, President of the Institute, is sold on the project ROV as a tool for teaching trainees what to expect when they get out in the field. "Building the CIGS II ROV taught the students hands-on practical exercises, teamwork, troubleshooting skills, and fly time," he says. "We make sure the six building blocks of project management - schedule, budget, design review, safety review, documentation, and operations - are used by the students." The ROV consists of a frame made from half-inch high-density polyethylene with stainless steel support bars. Three thrusters provide 30 pounds of thrust each and are rated to a depth of 250 feet (76m). The vehicle features four 130V/150W halogen shop lights that have been potted to withstand the depth pressure. A black and white chip camera is mounted in an underwater dive housing rated to 500 feet (152m). A fish finder simulates sonar capability.
Jon Shawl's Yel-O-Sub One member of this informative webring, Jon Shawl, successfully built a two-man mini sub called the Yel-O-Sub. Some of the specs are as follows:
For those interested in tackling a project of this type themselves, Shawl started an email group at his website, www.yel-o-sub.com. Some, like Shawl, have already built their own personal manned mini sub. "We, as a group, are planning on coming up with a practical sub idea and then we will go through all the design steps to come up with plans that could be used to build it," Shawl says. "We will also be learning more about the process of designing a sub as we go along. We have quite a varied group already. One person is planning on writing a book on the entire project."
Gary Boucher's "sports car" sub Boucher's sub is rated for 200 feet (61m), which he says is a conservative estimate. "I would estimate crush depth to be better than 600 feet," he says. "I have so far taken my sub to lakes in Arkansas and Texas. Most of the materials can be purchased locally or ordered off-shelf. There was a certain amount of machining that had to be performed with heavy machining equipment. The total for such machining was less than $1,000. I did most of the welding with a standard DC arc welding machine." Boucher is an electronics engineer, and his experience allowed him to automate much of the vehicle's systems using microprocessors. Data gathering from the power plant, electrical, and hydraulics systems run through two Motorola processors. His sub project required knowledge of physics, hydraulics, and numerous mechanical systems. However, with the exception of microprocessor electronics, Boucher says much of the design could be handled by most people with good concepts of mechanical and electrical knowledge. Boucher uses his sub much the same as some people use a sports car. He wanted a relatively fast sub that might remind someone of the WWII boats, and designed the vehicle with this goal in mind. However, other home designers go for the touring model for slow speed and high visibility. On a dive at a lake in Arkansas, Boucher remembers cruising for about a half hour at a depth of around 30 feet (9m) deep. "I looked at the bottom sounding sonar and it indicated that the bottom was more than 100 feet (30m) below me at the time. I remember feeling like I was over the abyss. It is a strange feeling the first time that you know that you might not escape if a serious problem arose. You know the bottom is there but you don't like to think about going there unexpectedly." Boucher is still tinkering with the equipment on the sub. "I have been doing research in the field of collision avoidance using scanning sonar. As part of this research, I designed and constructed a scanning sonar system capable of being mounted on my sub. The one thing needed to make it operational is a visual display capable of depicting 3D sonar returns. I hope to have this system finished and installed next summer." Another vehicle could be in the works, as well. "I may build a sport submersible capable of moving through the water in any attitude or roll position," he says. "This can be done by locating the center of buoyancy and the center of gravity at nearly the same location after submersion. In this way there is no roll or pitch torque, allowing the sub to 'fly' through the water much the same as an aerobatic sport plane would using the proper control surfaces."
Safety first Of his maiden submarine voyage, Gary Boucher admits, "I did not know how I would feel taking it down for the first time, but I had thought the systems out so many times and thought of as many What Ifs as I could, so I felt comfortable. I was perhaps a little excited, but not really afraid to dive the sub for the first time. On the first set of dives, I was at around 20 feet (6m) deep when I heard what sounded inside the hull like a great amount of water flowing into the sub's interior. A few pieces of debris got stuck in a check valve and allowed a slow flow of water to overflow a trim tank inside the hull. This got my attention faster than any other event of the day." Thankfully, the incident was not serious and only resulted in the thorough soaking of a few towels while drying the inside, but this is an example of what can happen with a do-it-yourself vehicle. Although most homemade underwater vehicles are not really practical for industrial applications outside of camera inspections, the thrill for do-it-yourselfers seems to be in the chase. The joy is in asking the question of themselves, "Can I do this?" The joy is in the work that takes them through the design, planning, and building stages. And the ultimate joy is in getting the vehicle in the water and finally proving the answer to the question, "Yes, I can."
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