I told JD where to look, and he navigated the craft around the habitat to the top of the control room. The floodlights spotlit the way, and we searched the hull.
It didn't take long to find the device.
I zoomed in with a high-definition camera and recognized it right away.
I rushed to the lockout chamber, sealed the hatch behind me, and opened the bottom hatch. I put on my fins and mask, then shouldered the harness for the bailout bottle and put the regulator in my mouth. There was enough oxygen left for a short dive, much more time than I would need.
Only seconds remained as I grabbed a plasma torch and a pry bar, then plunged into the frigid water.
Cold shock rippled through me as I swam toward the device. It was an M97x—an advanced Russian design. Common among terrorist groups and non-state actors. I was familiar with the device’s layout.
This one looked a little enhanced. It had a tapered conical metallic casing. Inside, neodymium magnets attached it to the hull with 500 kg of force. Not something you could easily pry off. And even if you could, there was an anti-tamper plunger that would detonate once you pulled it away. The M97x also had electronic tilt sensors that could detect removal attempts.
The device was filled with PBX with HMX or CL-20. Perhaps C4 or even Semtex. All of which were highly stable and needed an intense shock from a blasting cap to detonate. The plastic explosive could withstand dramatic thermal changes and casual impacts and wouldn’t explode. It took an abrupt action to trigger.
The M97x had a digital exploding foil initiator, triggered by a high-voltage pulse. The booster used nano-thermite for faster initiation. Inside, the whole thing was controlled by an electronic circuit board and could be fitted with Bluetooth or an acoustic modem for remote operation, most likely the latter in this scenario. The device hinged on a power source, which would trigger the detonator, which would then cause the C4 or PBX, or whatever the hell it was, to do its dirty business. Most limpet mines were powered by a 9V battery. But the M97x had a sealed lithium-ion battery.
If I could disable the power source, it would render the device safe.
But that was a bigif.
The explosive compound was located in the conical section. Below it were the magnets, circuitboard, power source, and anti-tamper switches. All of which were accessible from the faceplate on the other side. The faceplate that you couldn't get off once it was attached to the hull of the ship or a subsea habitat.
It wasn’t the first time I had disabled one of these things. I knew the basic layout of the components. But anything can change. Customizations can be made.
I tapped the base of the device with the prybar, listening for hollow and solid sections.
I looked at my dive watch.
19 seconds left…
18…
17…
My heart thumped my chest. I breathed heavily.
41
This was the moment of truth. I was pretty certain I knew where the battery compartment was. While the plastic explosive was insensitive to thermal shock, excessive heat could trigger the detonator. The device could instantly explode. No bueno.
In roughly 15 seconds, it was going to explode anyway.
There weren’t many options at this point. I placed the plasma torch against the casing with shaky hands and fired a brief pulse through the metal, and hopefully into the battery compartment.
I don't know if you've ever seen a lithium battery on fire, but you can't put one out until it exhausts itself.
Underwater, the pinpoint strike at 30,000° vaporized the battery’s sealed casing and internal separators. Volatile organic compounds off-gassed with a hiss of bubbles. The battery dumped its energy. Voltage collapsed to zero almost instantaneously.
Bubbles continued with fury.
I figured I had hit the right spot. I got the hell out of there and swam back to the mini-sub. There was no point hanging around. If it was going to detonate, it would detonate.
3…
2…
I climbed into the lockout chamber, pulled off my mask, and spit out the regulator. Trembling again, I slipped the harness from my shoulders, took off my fins, and sealed the bottom hatch. Then I opened the hatch to the main compartment and joined the others.
