This post is based upon a presentation by robotics engineer John Griffiths and Alicia Dunn at the Norfolk Island Knowledge and Learning Centre, Norfolk Island, on 5 July 2024. It is re-published here because of the potential of this technology for cost-competitive environmental management, the control of Crown of Thorns Starfish in Queensland being just one example. For an article on COTS, see https://scienceqld.org/2024/08/20/cots/

History
Underwater drones or ROVs, short for “remotely operated vehicles”, first saw commercial use in the oil and gas industry for inspecting oil rig structures. They were giant machines the size of a large vehicle that took multiple people to deploy and control. By the 1980s, they were well recognised as being safer, more cost-effective and – with tools mounted on them – more capable than sending down divers, particularly to the depths at which most of the work required of them was conducted. However, the cost of such machines was so great that only very few industries or institutes could afford one. A few companies realised the potential of building smaller and smaller units. The cost of research and development and the low production numbers meant that they were very expensive so the uptake and awareness of their availability was very low.

The development of aerial drones saw miniaturisation of the electronic systems needed to fly them. It quickly became apparent that with changes to the software, much of those electronics could control underwater motors and could stream video to a screen through a tether, usually consisting of twisted pairs of copper inside protective casing. While these units were limited to just being able to send video with tethers less than 100 metres, and were often subject to failure-prone electronics or leaky housings, it put the price within the range of the average consumer and sparked the interest of hobbyists all over the world.

Our personal journey
Our personal journey into the world of underwater drones started on Norfolk Island at about that time – in 2015. The Island had been through a particularly bad patch of weather with very few fresh fish being caught. Frustrated with the fish options being Nile Perch or Bass freighted from the other side of the world, John Griffiths had the idea he could make a remotely controlled submarine of some sort with a spear gun on it that he could use off the rocks on the sheltered sides of the Island. He could see that the concept had considerable merit if it could be implemented. It would mean selective targeting of only the fish the user wanted, with no bycatch, providing a dependable source of high-grade protein that was environmentally sustainable and had a far lower carbon footprint than anything shipped in from overseas. It was obvious that a spear gun on an underwater drone could also be used for tagging sharks or collecting DNA for research. The problem was that nothing remotely capable of firing a spear was on the market so he set about trying to make one.

After more than a year of frying numerous electronics components in leaking PVC tubes from Bunnings and trying to find motors that would work, a guy in a backyard garage in California put some waterproof motors he had designed on Kickstarter and in the months later started making waterproof tubes, an improved motor and various components including a robotic claw. Suddenly, everything needed to make a functional underwater drone capable of firing a spear gun was available. Lots of trial and error followed with various types of spear guns and actuators. It very soon became apparent that the system that could fire a spear gun also could control any number of mechanical tools. John took the approach that his underwater drones and tools should be designed to allow for tools to be changed in matter of minutes like a tractor changing from having a post hole borer to a rotary hoe or even carrying multiple tools for various functions at the same time. What followed was year after year of constant research and development where tools as varied as pneumatic drills, golf ball collectors and crown-of-thorns starfish injectors to name a few were developed. Fast forward to now, as well as being the only makers in the world of a spear gun attachment for underwater drones, our firm designs and builds underwater drones for any purpose that has an environmental benefit. One of our designs won a NSW design award and is the most hydrodynamic industrial grade underwater drone in the world and features artificial intelligence for anomaly detection on ship hulls.

Now we are finishing the world’s first marine debris-collecting underwater drone complete with twin disc cutters and deployable grappling hook designed to remove abandoned fishing nets and lobster pots, sunken vessels, tyres or anything else damaging marine environments. All over the world, businesses that previously relied on divers to do their work, now realise that an underwater drone with the right tool is a far cheaper and more effective way to perform multiple functions at the same time.

While we focus primarily on design and building specific use underwater drones, a number of other companies have developed sophisticated electronics for these small drones so that now plug and play sonar, position holding, location tracking, temperature and depth gauges are just off-the-shelf upgrades many underwater drones are equipped with. The potential uses of underwater drones are expanding by the day and the market is increasing at a rapid rate.

Just some of things an ROV can do
1. Data collection such by high resolution video, sonar and lidar images, laser measurements, temperature and depth gauges, are now standard capabilities.
2. Food harvesting such as spearfishing, sea cucumber, sea urchin, crayfish, scallops, hook and line fishing can all be done with an ROV.
3. Also with a spear gun mounted on an ROV, shark tagging and DNA collection could be done with far less trauma and physical damage to the shark than current methods allow.
4. Invasive marine species control. An ROV equipped with our Crown of Thorns Starfish injector or the tool we have developed for rogue urchin eradication would go a long way to solving the problems that devastate large sections of the Great Barrier Reef and the kelp beds of much of NSW, Victoria, Tasmania. These are just two of the problems caused by invasive marine species world-wide. There are many other ROV-mountable tools that could be developed to address these problems.
5. Marine debris collection. Marine debris comes in many shapes and forms but we know that the breakdown of the debris is filling the ocean with tiny particles that are ending up in the entire food chain, including the seafood that we eat. A suitably equipped ROV can cut cables, wires, rope, retrieve large items with a trapping hook and airbag.
6. Infrastructure inspection for cracks from dam walls to oil rigs pylons to jetties.
7. Fish-farm net repair and removal of dead fish.
8. Search and rescue. An ROV with an air tank can power pneumatic tools such as hammers to smash into submerged vehicles or boats, while robotic arms can extricate a person. The quick deployability of an ROV makes them far better suited for the role, particularly where depth and water temperature are factors.
9. Subsea mining for the very high value minerals found concentrated on parts of the ocean floor.
10. Ship hull inspection for anomalies like cracks or even contraband and also biofouling detection.

Reducing bycatch when fishing
Fish are a great source of healthy protein and societies all over the world that have high levels of sea food in their diet tend to be in better health and live longer. Here is where an ROV equipped with either a spear gun or a hook and line can be of great assistance. A spear gun allows you to select the fish you want and if your aim is right, you almost certainly have secured dinner. A rod mounted onto the ROV with the bait dangled in front of particular fish that you see is quite effective as well. This is a tool that we have just developed.

Potential for misuse
Like any technology the potential for misuse is high and we have at times destroyed prototypes of tools developed for one purpose when we realised they could be used in a very different and destructive way in unregulated fisheries around the world. It doesn’t take much imagination to see a future where 10,000 small AI-enhanced underwater drones, with just a few extra lines of code in the software, can be thrown over the side of a vessel in international waters, with that extra code telling them all to surface next Wednesday having grabbed everything they see of a certain size and colour.

They also can be armed relatively easily and something programmed for patrolling a submarine pen could easily be directed to sink a vessel. We are watching the emergence of this type of utilisation in the Ukraine/ Russia war and no doubt it will be part of any military arsenal of the future just as aerial drones are now.

Subsea mining is another area where great harm through misuse of this technology in fragile environments could occur.

This means that our firm is very careful about what we develop, what we show and what we make available. We are very cautious about who our buyers are and what is the intended usage of that underwater drone or tool design. Like the internet or nuclear arms, in the wrong hands, the world becomes a worse place. We design and build only things that we think can make the world a better place.

Down Deep Drones

info@downdeepdrones.com
www.downdeepdrones.com
26 July 2024

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