Hiding A Bomb In Plain Sight

March 7, 2026 by Al Williams 38 Comments

You are at war. Trains are key to keeping your army supplied with fuel, ammunition, food, and medical supplies. But, inexplicably, your trains keep blowing up. Sabotage? Enemy attack? There’s no evidence of a bomb or overt enemy attack. This is the situation the German military found itself in during World War II. As you can see in the video below, the hidden bomb was the brainchild of a member of Britain’s SOE.

The idea was to put plastic explosive inside a fake plastic lump of coal. They hand-painted each one, and the color had to match the exact appearance of local coal. Paint and coal dust helped with that. The bomb had to weigh the correct amount as well.

The coal was safe until it got quite hot, so resistance fighters could easily carry the coal and surreptitiously drop the bomb anywhere coal is stored. Eventually, it will be put in a boiler, and at the right temperature, it will do its job. There’s some actual footage of a test in the second video below.

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SpyTech: The Underwater Wire Tap

March 5, 2026 by Al Williams 20 Comments

In the 1970s, the USSR had an undersea cable connecting a major naval base at Petropavlovsk to the Pacific Fleet headquarters at Vladivostok. The cable traversed the Sea of Okhotsk, which, at the time, the USSR claimed. It was off limits to foreign vessels, heavily patrolled, and laced with detection devices. How much more secure could it be? Against the US Navy, apparently not very secure at all. For about a decade starting in 1972, the Navy delivered tapes of all the traffic on the cable to the NSA.

Top Secret

You need a few things to make this a success. First, you need a stealthy submarine. The Navy had the USS Halibut, which has a strange history. You also need some sort of undetectable listening device that can operate on the ocean floor. You also need a crew that is sworn to secrecy.

That last part was hard to manage. It takes a lot of people to mount a secret operation to the other side of the globe, so they came up with a cover story: officially, the Halibut was in Okhotsk to recover parts of a Soviet weapon for analysis. Only a few people knew the real mission. The whole operation was known as Operation Ivy Bells.

The Halibut

The Halibut is possibly the strangest submarine ever. It started life destined to be a diesel sub. However, before it launched in 1959, it had been converted to nuclear power. In fact, the sub was the first designed to launch guided missiles and was the first sub to successfully launch a guided missile, although it had to surface to launch.

Oddly enough, the sub carried nuclear cruise missiles and its specific target, should the world go to a nuclear war, was the Soviet naval base at Petropavolvsk.

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Inside SKALA: How Chornobyl’s Reactor Was Actually Controlled

March 3, 2026 by Maya Posch 13 Comments

Entering SKALA codes during RBMK operation. (Credit: Pripyat-Film studio)

Running a nuclear power plant isn’t an easy task, even with the level of automation available to a 1980s Soviet RBMK reactor. In their continuing efforts to build a full-sized, functional replica of an RBMK control room as at the Chornobyl Nuclear Power Plant – retired in the early 2000s – the [Chornobyl Family] channel has now moved on to the SKALA system.

Previously we saw how they replicated the visually very striking control panel for the reactor core, with its many buttons and status lights. SKALA is essentially the industrial control system, with multiple V-3M processor racks (‘frames’), each with 20k 24-bit words of RAM. Although less powerful than a PDP-11, its task was to gather all the sensor information and process them in real-time, which was done in dedicated racks.

Output from SKALA’s DREG program were also the last messages from the doomed #4 reactor. Unfortunately an industrial control system can only do so much if its operators have opted to disable every single safety feature. By the time the accident unfolded, the hardware was unable to even keep up with the rapid changes, and not all sensor information could even be recorded on the high-speed drum printer or RTA-80 teletypes, leaving gaps in our knowledge of the accident.

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Reflections On Ten Years With The Wrencher

February 27, 2026 by Jenny List 26 Comments

An auspicious anniversary passed for me this week, as it’s a decade since I started writing for Hackaday. In that time this job has taken me all over Europe, it’s shown me the very best and most awesome things our community has to offer, and I hope that you have enjoyed my attempts to share all of that with you. It’s worth a moment to reflect on the last ten years in terms of what has made our world during that time. Continue reading “Reflections On Ten Years With The Wrencher” →

What One-Winged Squids Can Teach The Airship Renaissance

February 25, 2026 by Tyler August 31 Comments

It’s a blustery January day outside Lakehurst, New Jersey. The East Coast of North America is experiencing its worst weather in decades, and all civilian aircraft have been grounded the past four days, from Florida to Maine. For the past two days, that order has included military aircraft, including those certified “all weather” – with one notable exception. A few miles offshore, rocking and bucking in the gales, a U.S. Navy airship braves the storm. Sleet pelts the plexiglass windscreen and ice sloughs off the gasbag in great sheets as the storm rages on, and churning airscrews keep the airship on station.

If you know history you might be a bit confused: the rigid airship USS Akron was lost off the coast of New Jersey, but in April, not January. Before jumping into the comments with your corrections, note the story I’ve begun is set not in 1933, but in 1957, a full generation later.

The airship caught in the storm is no experimental Zeppelin, but an N-class blimp, the workhorse of the cold-war fleet. Yes, there was a cold war fleet of airships; we’ll get to why further on. The most important distinction is that unlike the last flight of the Akron, this story doesn’t end in tragedy, but in triumph. Tasked to demonstrate their readiness, five blimps from Lakehurst’s Airship Airborne Early-Warning Squadron 1 remained on station with no gaps in coverage for the ten days from January 15th to 24th. The blimps were able to swap places, watch-on-watch, and provide continuous coverage, in spite of weather conditions that included 60 knot winds and grounded literally every other aircraft in existence at that time. Continue reading “What One-Winged Squids Can Teach The Airship Renaissance” →

How To Restore Your 19th-Century Lancashire Boiler To Hold 120 PSI

February 23, 2026 by Maya Posch 14 Comments

The Industrial Revolution was powered by steam, with boilers being a crucial part of each steam engine, yet also one of the most dangerous elements due to the high pressures involved. The five Lancashire boilers at the Claymills Pumping Station are relatively benign in this regard, as they operate at a mere 80 PSI unlike e.g. high-pressure steam locomotives that can push 200 – 300 PSI. This doesn’t mean that refurbishing one of these boilers is an easy task and doesn’t involve plugging a lot of leaks, as the volunteers at this pumping station found out.

At this Victorian-era pumping station there are a total of five of these twin-flue Lancashire boilers, all about 90 years old after a 1930s-era replacement, with them all gradually being brought back into service. The subject of the video is boiler 1, which was last used in 1971 before the pumping station was decommissioned. Boilers 2 and 3 were known to be in a pretty bad condition, and they needed a replacement for boiler 5 as it was about to go down for maintenance soon.

Although the basic idea behind a Lancashire boiler is still to boil water to create steam, it’s engineered to do this as efficiently as possible to save fuel. This is why it has two flues where the burning coal deposits its thermal energy, which then goes on to heat the surrounding water. The resulting pressure from the steam also means that there are a lot of safeties to ensure that things do not get too spicy.

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Retrotechtacular: Bleeding-Edge Memory Devices Of 1959

February 21, 2026 by Maya Posch 6 Comments

Although digital computers are – much like their human computer counterparts – about performing calculations, another crucial element is that of memory. After all, you need to fetch values from somewhere and store them afterwards. Sometimes values need to be stored for long periods of time, making memory one of the most important elements, yet also one of the most difficult ones. Back in the 1950s the storage options were especially limited, with a 1959 Bell Labs film reel that [Connections Museum] digitized running through the bleeding edge of 1950s storage technology.

After running through the basics of binary representation and the difference between sequential and random access methods, we’re first taking a look at punch cards, which can be read at a blistering 200 cards/minute, before moving onto punched tape, which comes in a variety of shapes to fit different applications.

Electromechanical storage in the form of relays are popular in e.g. telephone exchanges, as they’re very fast. These use two-out-of-five code to represent the phone numbers and corresponding five relay packs, allowing the crossbar switch to be properly configured.

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