The news comes from a study published in a Chinese journal, regarding detection of the most advanced American submarines. The stealthiest examples use all kinds of sophisticated systems to damp vibrations and reduce acoustic signatures to make detection as hard as possible. However, a new type of magnetic detector could change all that.
A research team used computer simulations to determine whether nuclear-powered submarines could be detected via the bubbles produced when cruising at high speed underwater. When these bubbles inevitably collapse, it can apparently produce a detectable signal that is orders of magnitude higher than the sensitivity of the best magnetic anomaly detectors. The signal is found on the order of 34.19 to 49.94 Hz, deep in the ELF range, according to researchers.
This could yet create another arms race, as submarine designers begin designing vessels to reduce bubble shedding at speed. Or, for all we know, this is already a well-known principle in the high-stakes world of submarine surveillance and combat. If you’re in the know, please don’t reveal any classified information in the comments section. It’s not worth your job or ours! If you recreate such a detector at home in a non-treasonous manner, though, don’t hesitate to let us know!
Donald Reid had a passion for applying himself to challenging problems, and in many ways his life’s work was that of developing a prototype submersible aircraft — or flying submarine — for which his son Bruce was a test pilot. [Jesse Moody] brought to our attention a fantastic documentary he created (with a short teaser trailer here) in which he interviews Bruce, and in the process teaches us all about a story that spanned decades and formed an important part of aviation history. Bruce experienced his share of hair-raising moments while testing the craft, but still has all of his fingers and limbs. Still, in his own words, “you wouldn’t be doing that kind of testing today!”
In many ways, the story revolves around defying assumptions. Without context, a “flying submarine” project might sound like a lone kook’s obsession, but Donald Reid was nothing of the sort. He was a brilliant engineer who was able solve problems by applying his skill and intellect with a laser-like focus. And it turns out that getting a submerged vehicle to successfully transition from waterbound craft to airborne is a source of numerous and novel problems that were not trivial to solve. In fact, these problems needed to be solved in order to develop the Tomahawk cruise missile, which is launched by submarine. And that brings us to the lawsuit that bookended it all.
[Tom Scott] has traveled the world to see interesting things. So when he’s impressed by a DIY project, we sit up and listen. In this case, he’s visiting the Bathysphere, a project created by a couple of passionate hobbyists in Italy. The project is housed at Explorandia, which based on google translate, sounds like a pretty epic hackerspace.
The Bathysphere project itself is a simulation of a submarine. Sounds simple, but this project is anything but. There are no VR goggles involved. Budding captains who are up for the challenge find themselves inside the cockpit of a mini-submarine. The sub itself is on a DIY motion platform. Strong electric motors move the system causing riders to feel like they are truly underwater. Inside the cockpit, the detail is amazing. All sorts of switches, lights, and greebles make for a realistic experience. An electronic voice provides the ship status, and let’s the crew know of any emergencies. (Spoiler alert — there will be emergencies!)
The real gem is how this simulation operates. A Logitec webcam is mounted on an XY gantry. This camera then is dipped underwater in a small pond. Video from the camera is sent to a large monitor which serves as the sub’s window. It’s all very 1960’s simulator tech, but the effect works. The subtle movements of the simulator platform really make the users feel like they are 20,000 leagues under the sea.
Check out the video after the break for more info!
The “caterpillar drive” in The Hunt for Red October allowed the sub to travel virtually undetected through the ocean, but real examples of magnetohydrodynamic drives (MHDs) are rare. The US Navy’s recently announced Principles of Undersea Magnetohydrodynamic Pumps (PUMP) intends to jump-start the technology for a new era.
Dating back to the 1960s, research on MHDs has been stymied by lower efficiencies when compared with driving a propeller from the same power source. In 1992 the Japanese Yamato-1 prototype, pictured at the top of the page, was able to hit a blistering 6.6 knots (that’s 12 kph or 7.4 mph for you landlubbers) with a 4 Tesla liquid helium-cooled MHD. Recent advances courtesy of fusion research have resulted in magnets capable of generating fields up to 20 Telsa, which should provide a considerable performance boost.
The new PUMP program will endeavor to find solutions for more robust electrode materials that can survive the high currents, magnetic fields, and seawater in a marine environment. If successful, ships using the technology would be both sneakier and more environmentally friendly. While you just missed the Proposers Day, there is more information about getting involved in the project here.
About two years ago, [Hyperspace Pirate] set to work on building his own two-seater submarine, because who doesn’t want to have a submarine when you have just moved to Florida? In the linked video (also attached below), he describes the reasoning behind the submarine design. Rather than going with a fully sealed submarine with ambient pressure inside and a hull that resists the crushing forces from the water, he opted to go for a semi-wet ambient pressure design.
What this essentially entails is a fancy equivalent of an old-school diving bell: much as the name suggests, these are sealed except for the bottom, which allows for water to enter and thus equalize the pressure. Although this has the distinct disadvantage of being not dry inside (hence the semi-wet), it does mean that going for a dive is as easy as letting the water in via the bottom hole, and to resurface only a small amount of air injected into two ballast tanks and a pump are all that are required.
So far this submarine has survived a few test runs, which uncovered a number of issues, but diving and resurfacing seems to be going pretty smoothly now, which is definitely a massive plus with a submarine.
The projects featured on these pages frequently rule the air, the ground, the rails, and even the waves, but very rarely do they rule the deep. Building a submarine is hard, and thus it’s a challenge not taken on by all but the most courageous of builders. This hasn’t discouraged [Timo] though, who has embarked on the construction of what is shaping up to be a very nice underwater ROV build.
The design is straightforward enough, with a PVC tubing frame carrying thrusters for maneuvering, and a central tubular compartment for the electronics and a camera. Control and power comes via a wired connection, and there is a companion controller holding a Pi Pico interfaced to a PlayStation controller.
So far the craft is a work in progress, and he’s engaged in a battle with water pressure to keep in dry inside. The fittings are all 3D printed, and this means a constant battle with warped prints and collapsing infill. He’s not given up though, and is instead recovering enthusiasm by working on the shore-side controller.
Building an underwater remotely operated vehicle (ROV) is always a challenge, and making it waterproof is often a major hurdle. [Filip Buława] and [Piotr Domanowski] have spent four years and 14 prototypes iterating to create the CPS 5, a 3D printed ROV that can potentially reach a depth of 85 m.
FDM 3D prints are notoriously difficult to waterproof, thanks to all the microscopic holes between the layers. There are ways to mitigate this, but they all have limits. Instead of trying to make the printed exterior of the CPS 5 waterproof, the electronics and camera are housed in a pair of sealed acrylic tubes. The end caps are still 3D printed, but are effectively just thin-walled containers filled with epoxy resin. Passages for wiring are also sealed with epoxy, but [Filip] and [Piotr] learned the hard way that insulated wire can also act as a tube for water to ingress. They solved the problem by adding an open solder joint for each wire in the epoxy-filled passages.
For propulsion, attitude, and depth control, the CPS 5 has five brushless drone motors with 3D printed propellers, which are inherently unaffected by water as long as you seal the connectors. The control electronics consist of a PixHawk flight controller and a Raspberry Pi 4 for handling communication and the video stream to a laptop. An IMU and water pressure sensor also enable auto-leveling and depth hold underwater. Like most ROVs, it uses a tether for communication, which in this case is an Ethernet cable with waterproof connectors.