A Survey Of Long-Term Waterproofing Options

March 27, 2023 by Matthew Carlson 27 Comments

When it comes to placing a project underwater, the easy way out is to just stick it in some sort of waterproof container, cover it with hot glue, and call it a day. But when you need to keep water out for several years, things get significantly harder. Luckily, [Patricia Beddows] and [Edward Mallon] from the Cave Pearl Project have written up their years of experience waterproofing data loggers for long-term deployment, making the process easier for the rest of us.

It starts with the actual board itself. Many SMD boards have at least some flux left over from the assembly process, which the duo notes has a tendency to pull water in under components. So the first step is to clean them thoroughly with an ultrasonic cleaner or toothbrush, though some parts such as RTCs, MEMs, or pressure sensors need to be handled with significant care.

Actual waterproofing starts with a coating like 422-B or nail polish which each have pros and cons. [Patricia] and [Edward] often apply coatings to PCBs even if they plan to otherwise seal it as it offers a final line of defense. The cut edges of PCBs need to be protected so that water can’t seep between layers, though care needs to be made for connectors like SD cards.

Encapsulation with a variety of materials such as hot glue, heat shrink tubing, superglue and baking soda, silicone rubber, liquid epoxy, paste epoxy (like J-B Weld), or even wax are all commented on. The biggest problem is that a material can be waterproof but not water vapor proof. This means that condensation can build up inside a housing. Temperature swings also can play havoc with sealings, causing gaps to appear as it expands or contracts.

Overall, it’s an incredible guide with helpful tips and tricks for anyone logging data underwater for science or even just trying to waterproof their favorite watch.

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Gaze Upon The Swimming Mechanical Stingray, Made With LEGO

December 10, 2022 by Donald Papp 5 Comments

Stingrays have an elegant, undulating swimming motion that can be hypnotic. [Vimal Patel] re-created this harmony with his fantastic mechanical mechanical stingray using LEGO pieces and a LEGO Technics Power Functions motor. The motor is set in a clever arrangement that drives the motion remotely, so that it and electrical elements can stay dry.

The mechanical stingray sits at the end of a sort of rigid umbilical shaft. This shaft connects the moving parts to the electrical elements, which float safely on the surface. This leaves only the stingray itself with its complex linkages free to move in the water, while everything else stays above the waterline.

We’ve seen some impressive LEGO creations before, like this race car simulator and pneumatic engine, and the mechanical action in this stingray is no exception. Interested in making your own? The part list and build directions are available online, and you can see it in action in the video embedded below.

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Love Is A Burning Flame, And So Is This Underwater Burning Ring Of Fire

July 29, 2022 by Ryan Flowers 22 Comments

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.

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All Dressed Up And Nowhere To Flow: Russia’s Nord Stream 2 Pipeline

April 24, 2022 by Ryan Flowers 38 Comments

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.

A Bubble Curtain containing the disposal of WW2 ordinance

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.

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That’s No Moon… It’s An Algae Robot

January 27, 2022 by Al Williams 10 Comments

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.

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Underwater Drone Films, Is In Film

January 22, 2022 by Al Williams 3 Comments

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.

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A Big Ship Chop Shop On The Georgia Coast

April 4, 2021 by Roger Cheng 16 Comments

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.