When Johnny Cash wrote “Ring of Fire”, he was talking about love. But when an unnamed follower of [TheBackyardScientist] took it literally and suggested making actual rings of fire — underwater — they rose to the challenge as you can see in the video below the break.
Of course there are several ingredients to underwater fire rings. First you need water, and a pool clearly does the job in this video. Second, you need flammable rings of gas. [TheBackyardScientist] decided to build a machine to create the gas rings, and it’s quite interesting to see them go through several iterations before settling on a voice coil based poppet valve design. We must say that it works absolutely swimmingly.
Lastly there needs to be fire. And for fire, you need something flammable, and something shocking. Forty thousands volts light up a spark plug, even underwater. The fuel is provided by what appears to be compressed air and acetylene but we’re not 100% sure. We are sure that it goes bang! quite sufficiently, as demonstrated by its aptitude for blowing things up.
We appreciated the engineering that went into the project but also the rapid iterations of ideas, the overcoming of serious obstacles and the actual science that went into the project. Even if it is just randomly making literal burning rings of fire.
At over 1230 km (764 mi) in length, $10 billion in cost, and over a decade in the making, the Nord Stream 2 pipeline was slated to connect the gas fields of Russia to Western Europe through Germany. But with the sanctions against Russia and the politics of the pipeline suffering a major meltdown, this incredible feat of engineering currently sits unused. What does it take to lay so much underwater pipe, and what challenges are faced? [Grady] over at Practical Engineering lays out out nicely for us in the video below the break.
As with any undersea pipeline or cable, a survey had to be done. Instead of just avoiding great chasms, underwater volcanos, or herds of sharks with lasers, planners had to contend with culturally important shipwrecks, territorial waters, and unexploded ordnance dating from the second world war. Disposing of this ordinance in a responsible way meant employing curtains of bubbles around the explosion to limit the propagation of the explosion through the water- definitely a neat hack!
Speeding up the job meant laying several sections of pipe at once, and then tying them together after they were laid. The sheer amount of engineering, manpower and money involved are nothing short of staggering. Of course [Grady] makes it sound simple, and even shares his take on some of the geopolitical issues involved, such as Germany refusing to certify the line for use after the Russian invasion of Ukraine. So far, the $10 billion pipeline is unused, and even Shell has walked away from its $5 billion investment.
Be sure to watch the whole video for even more fascinating details about the Nord Stream 2’s amazing engineering and construction. Check out a Robot Eel concept for the maintenance of underwater pipelines too.
When you think of a robot, you probably don’t think of a ball of underwater algae. But a team of university researchers used a 3D-printed exoskeleton and a ball of marimo algae to produce a moving underwater sensor platform. It is really at a proof-of-concept stage, but it seems as though it would be possible to make practical use of the technology.
Marimo are relatively rare balls of algae that occur in some parts of the world. A robot powered by algae runs on sunlight and could be electromagnetically quiet.
Having a drone that can follow you running or biking with a camera isn’t big news these days. But French firm Notilo Plus has an underwater drone that can follow and video an underwater diver. The Seasam has been around since 2019, but recently made an appearance in a French film, The Deep House about a couple exploring an underwater haunted house, as reported by New Atlas. You can see a video about the drone — and a trailer for the movie — in the videos below.
To follow a diver, the robot uses an acoustic signal from the user’s control unit to find the approximate location of the user. This works even in dark conditions. Once close enough, computer vision zeros in on the diver while a sonar system allows safe navigation.
Last week we saw a hapless container ship vaulted to fame, where people converged on its combination of mind-boggling size suffering an easily relatable problem of getting stuck. Now that it is moving again, armchair engineers who crave more big ship problem-solving should check out [David Tracy]’s writeup on the salvage operation of an overturned car carrier ship, the MV Golden Ray published by Jalopnik. If the ship’s name doesn’t ring a bell, the writeup opens with a quick recap.
Written for an audience of gearheads, [Tracy]’s writeup walks through some technical aspects of the salvage plan and initial results of execution. Citing from the official entity in charge, the St. Simons Sound Incident Response Unified Command, and augmented with information from elsewhere. Even though the MV Golden Ray is “only’ half the length and a third of the gross tonnage of our meme darling MV Ever Given, it is still a huge ship. Every salvage operation this big is unique, requiring knowledge far beyond our everyday intuition. At this scale, most Internet “Why don’t they just…” comments range from impractical to absurd.
Fortunately, people who actually know how to perform salvage work designed plans, submitted by multiple bidders, each making a different tradeoff in cost and speed among other factors. The chosen plan was to cut the ship into sections small enough to be carried by barge for further processing elsewhere. This required a huge floating crane, a chain pressed into cutter duty, custom fabricated lugs for lifting, and similarly custom fabricated cradles for the barges.
But we all know that no plan survives contact with reality. While this plan was seemingly chosen for speed, it hasn’t gone nearly as fast as advertised. Certainly the pandemic was a huge hinderance, but cutting has also been slowed by pieces built far stronger than spec. Delays also meant more sediment buildup inside the wreck, compounding headaches. Other bidders have started saying that if their plan had been chosen the job would be done by now, but who’s to say their plan wouldn’t have encountered their own problems?
In time St. Simons Sound will be cleared as the Suez Canal has been. Results of their respective investigations should help make shipping safer, but salvage skills will still be needed in the future. At least this operation isn’t as controversial as trying to retrieve the radio room of RMS Titanic.
Robotics has advanced in leaps and bounds over the past few decades, but in terms of decentralized coordination in robot swarms, they far behind biological swarms. Researchers from Harvard University’s Weiss Institute are working to close the gap, and have developed Blueswarm, a school of robotic fish that can exhibit swarm behavior without external centralized control.
In real fish schools, the movement of an individual fish depends on those around it. To allow each robotic fish to estimate the position of its neighbors, they are equipped with a set of 3 blue LEDs, and a camera on each side of the body. Four oscillating fins, inspired by reef fish, provide 3D control. The actuator for the fins is simply a pivoting magnet inside a coil being fed an alternating current. The onboard computer of each fish is a Raspberry Pi W, and the cameras are Raspberry Pi Camera modules with wide-angle lenses. Using the position information calculated from the cameras, the school can coordinate its movements to spread out, group together, swim in a circle, or find an object and then converge on it. The full academic article is available for free if you are interested in the details.
Communication with light is dependent on the clarity of the medium it’s traveling through, in this case, water — and conditions can quickly become a limiting factor. Submarines have faced the same challenge for a long time. Two current alternative solutions are ELF radio and sound, which are both covered in [Lewin Day]’s excellent article on underwater communications.
Underwater exploration and research can be exceedingly dangerous, which is why remotely operated vehicles (ROVs) are so commonly used. Operators can remotely command these small submersibles to capture images or collect samples at depths which would otherwise be unreachable. Unfortunately, such technology comes at a considerable price.
Believing that the high cost of commercial ROVs is a hindrance to aquatic conservation efforts, [Noeël Moeskops] has been developing an open source modular ROV he calls Aruna. Constructed largely from off-the-shelf components and 3D-printed parts, the Aruna promises to be far more affordable than anything currently on the market. Hopefully cheap enough to allow local governments and even citizens to conduct their own underwater research and observations.
More than just the ROV itself, Aruna represents an entire system for developing modular underwater vehicles. Whether you decide to build the boilerplate ROV documented and tested by [Noeël], or implement individual components into your own design, the project is a valuable source of hardware and software information for anyone interested in DIY underwater robotics.