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Imagine you had a drone that could dive to the ocean floor, pick up a chunk of rock, fly up one foot above the deck and drop the rock, then fly back down and re
by asdff 4y ago
Imagine you had a drone that could dive to the ocean floor, pick up a chunk of rock, fly up one foot above the deck and drop the rock, then fly back down and repeat. Imagine you had 10 thousand of these swarming a single aircraft carrier. You'd be able to sink it before long, and the poor sailors aboard will have no defence against 10 thousand tiny machines that only appear for a second and are all around the ship. Anything you fire at them is liable to damage the ship itself.
Maybe you wouldn't even need to have them come above the water line. Maybe the drone is just a weight and a magnet that can clamp onto the ships haul below the water line. Again, you can't combat that without having thousands of divers below your ship scraping the hull.
- CamperBob2 4y agoImagine you had a drone that could dive to the ocean floor, pick up a chunk of rock, fly up one foot above the deck and drop the rock, then fly back down and repeat That would take a ridiculous amount of energy.
- kragen 4y agoIf we suppose we have to stack 100'000 more tonnes of rock on top of a 100'000 tonne displacement aircraft carrier to sink it, and the ocean is 2 km deep at that point, it takes about 1.96 terajoules at 100% efficiency. At 46 MJ/kg that's 43 tonnes of gasoline. That is a ridiculously small amount of energy to sink a carrier; it's maybe a large gas station. Of course the question is open: how efficient would the rock-stacking drones be? If they're 50% efficient the scale of the operation is different than if they're 0.05% efficient.
- CamperBob2 4y agoSeems that energy will need to be expended in both directions, given that you're working in the opposite direction of the usual diving practice where a weighted diver sinks to the bottom and releases ballast to come back up. Is that being accounted for? Also, I imagine somebody will notice this rock-stacking activity at some point over the (days? weeks?) it will to swamp the aircraft carrier, and take care of the problem with plain old birdshot. Or just a bunch of sailors with brooms or fire hoses. Failing that, just cruise away from the drone swarm. They'll run out of gas long before the carrier runs out of U235.
- kragen 4y agoIt's easier to change your buoyancy by releasing ballast, but that's not the only option, or the best option in this context. You can instead adiabatically expand a vacuum space (for example, in a cylinder with a piston) against water pressure to go from negative to positive buoyancy. 100'000 tonnes is 100 million kg, so for a million drones it would be 100 dives. I agree that stacking rocks on the deck of a carrier, or even gluing or magnet-clamping them to its hull, is probably not the most effective way for drones to damage it. Firing birdshot at sailors, for example, would be more effective; blinding them with lasers more effective still. The point is that even ridiculously primitive attacks become effective when you multiply them by enough orders of magnitude.
- r00fus 4y agoAs long as we're imagining we could use that same amount of energy and drop tungsten rods from orbit. https://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment
- kragen 4y agoYou clearly haven't done the relevant calculations.
- WastingMyTime89 4y agoIf someone had the technology to make a drone able to dive 3.7km to the bottom of the ocean, had enough strength to bring back a rock and then propel itself 40m above the surface and keep that small, your scenario would be the least of my worry. Anyway, if you are in position to bring something close to a carrier from underwater, an heavy torpedo will do the job for a lot less money that your swarm.