Usefulness of Kinetic Kill Weapons as Antisubmarine Weapons

[Zeropoint]

Blowing up the whole Atlantic to get one sub is not going to play well with the public.

[Cykeisme]

Inverse square law applies for surface detonations, right?

[Terralthra]

In a sense, yes, but it is complicated by the fact that force is not "radiated" equally in all directions from a surface impact with a direct downward vector, nor for an explosion on the water's surface. An explosion under the surface is roughly inverse square, with a few complicating factors like what happens when the shock front hits a thermocline.

[Simon_Jester]

Come to think of it, submarines are almost by definition hardened against hundreds of psi of overpressure. Nuclear depth charges were a thing in the Cold War, with good reason, but those were designed to be submerged in high-pressure water before initiating.

[Batman]

Subs are designed to survive a lot of overpressure, but only for a limited amount of 'a lot'. There's a reason for the term 'crush depth' and any overpressure (if any, I myself am dubious nonridiculous surface events are going to amount to much) created by such would be on top of the pressure the sub's already exposed to.

[Q99]

Blowing up the whole Atlantic to get one sub is not going to play well with the public.

Right.

Lesse, if you're hitting to a kill-depth of 2000 feet, then the shockwave is hitting the same killing capacity 2000 feet in every other direction, and lesser pressure far beyond. Killing all life in a a gigantic sphere of ocean.


Probably deafen whales a dozen miles away.

[Simon_Jester]

That is a gross underestimate; it takes a LOT less to deafen a whale than to crush a submarine.

Also, Batman, submarines rarely operate at or close to their crush depth if they can help it, because it's bad for the hull. So their ability to survive considerable extra overpressure factors in. And 'considerable' will typically mean 'dozens if not hundreds of psi.'

[Batman]

And I know that. My point was that while submarines are built to deal with overpressure, they're also constantly exposed to it, and them having a crush depth means there's a limit to what they can take. Any overpressure the weapon creates will come on top of the pressure the hull is already exposed to by virtue of operating at depth.

[Q99]

That is a gross underestimate; it takes a LOT less to deafen a whale than to crush a submarine.

A hundred miles away? It'll be a bad scene, in any case. You'll see dead sea creatures washing up on shores all over.

[Patroklos]

One of the problems with ideas like this is that the default assumption seems to be one of one set of future tech against otherwise largely static technology. If you have the ability to locate submarines with satellites, why does anyone still use them? Submarines actually aren't that hard to kill once you find them, the problem is finding them.

The only thing that it would make sense to build in that environment is surface vessels that are well defended with high power lasers and missiles. Maybe carriers, maybe just futuristic destroyers. It would almost be a situation akin to space combat in which detection is relatively easy.

At which point your satellites have the same problem. Once surface ships or any surface laser has the ability to destroy anything substantial within line of sight that means it can easily reach into orbit and kill a satellite as we know it. So you need to imagine a satellite with some sort of laser defense or stealth feature.

[Marko Dash]

IIRC some satellites today can find shallow running subs.

let's say your satellite picks up a hostile boomer coming up to launch depth, could the kkv even reach the surface in time? that's a lot of space and atmosphere to fall through.

[Caiaphas]

IIRC some satellites today can find shallow running subs.

let's say your satellite picks up a hostile boomer coming up to launch depth, could the kkv even reach the surface in time? that's a lot of space and atmosphere to fall through.

Wouldn't there also be an upper limit to your KKV velocity? I imagine that at a certain point it's travelling so quickly that it smacks into the steadily thickening atmosphere as though it's a brick wall.

[Khaat]

Wouldn't the transient nature of the impactor's over-pressure (or even directional compression passing along the hull) undermine the usual engineering concerns? Isn't that why depth charges work (they're irregular, unequal compression of the hull)?
Normal water pressure is a constant, regular pressure on the hull, while an "over-pressure event" would be a brief spike-then-release of pressure.

[EnterpriseSovereign]

As far as I can work out, the KKW would only be a threat if the sub was either surfaced or at least periscope depth.