Burning sub

Fireflair wrote:
Other countries don't spend their time and energy trying to hunt down subs in the wide ocean. If Russia, or China, or whomever, wants to have their subs puttering around at 5000m in the middle of the Atlantic, more power to them. There's nothing there and they're no danger to us. Certainly not to our subs.

Do you have the ability to find subs on 5000 meters depth?

Fireflair wrote:No, ballistic subs do not spend their time in the depths, even if they could hang out at 5000m they wouldn't. I was assigned to them, I know exactly where they spend time and it's not at depth.

As I pointed out previously, going deep doesn't do you any good. You can't get to land, or sneak up on land without hitting the continental shelf, which puts you back to shallow waters again.

Other countries don't spend their time and energy trying to hunt down subs in the wide ocean. If Russia, or China, or whomever, wants to have their subs puttering around at 5000m in the middle of the Atlantic, more power to them. There's nothing there and they're no danger to us. Certainly not to our subs.

There are a number of reasons the USN has opted out of titanium hills which would have allowed for deeper dives than HY-80 or HY-100 do. Foremost is that it's not useful to warfare in most any format to be able to dive that deep.

Unless you go all the way back to Polaris missilss, SSBNs have no need to get close to land. A sub armed with TRIDENT 2 missiles definately has no need to get close to land.

Boomers do not hang out at 5,000 meters because the cost and tradeoffs of building subs capable of diving to that depth is prohibitive. However; boomers don't hang out at 50 meters close to shore.

Point being, there's no reason to be at 5000m. Yes, if we wanted to hunt subs at 5000m we could do so. Sonar works the same at 5000m as it does at shallower depths, better in fact in many ways.

Again, subs don't run around at 5000m, there's no point. Ballistics can't launch missiles, ICBMs or Tomahawk style cruise missiles, from 5000m either. They have to be relatively shallow to do so. So you're not hunting ballistics at 5000m and the rest of the time they've got a whole wide ocean to hide in, which you won't find them in. Generally speaking.

Fireflair wrote:Point being, there's no reason to be at 5000m. Yes, if we wanted to hunt subs at 5000m we could do so. Sonar works the same at 5000m as it does at shallower depths, better in fact in many ways.

Again, subs don't run around at 5000m, there's no point. Ballistics can't launch missiles, ICBMs or Tomahawk style cruise missiles, from 5000m either. They have to be relatively shallow to do so. So you're not hunting ballistics at 5000m and the rest of the time they've got a whole wide ocean to hide in, which you won't find them in. Generally speaking.

The fact remains that diving depth equates to stealth. The deeper the sub, the less vulnerable to detection it is. This is why most subs are designed to dive to 200-300 meters rather than 20-30 meters. This diving depth comprimises speed and armament because most of the mass of the sub must be devoted to the pressure hull rather than the reactor, turbines, propulsion and weapons.

You clearly don't understand modern submarines and both their ability to avoid detection and detection technology. There is nothing gained at 5000m that isn't there at 800m when it comes to avoiding detection. Submarines actually prefer being at a few hundred meters.

And we're still back to the idea of avoiding detection in the shallows. You can't go to 5000m costal. If you're firing missiles, you have to be relatively shallow, so depth doesn't help.

There are no thermal layers below several hundred feet. Thermal layers are caused by surface heating, wave, and wind action. Below that, the water cools very slowly. There are some instances of warmer water very deep, but there are no sudden changes, which is what’s needed to form a layer useful for a submarine to hide in.

The hiding place is called a shadow zone. That location is below the MAXIMUM sound speed. At relatively shallow depths, maximum sound velocity coincides with MAXIMUM water temperature.

At deeper depths, pressure begins to control sound velocity. Eventually, the sound velocity will equal the shallow layer sound velocity. At that point, sound is refracted back up to the layer depth, where it is refracted down again. This area is called the Deep Sound Channel (DSC) or SOFAR Channel (Sound Fixing Or Ranging)

Essentially, the SOFAR is where a hiding submarine does NOT want to be. Any sensor at that depth (submarine, towed array, VDS, SOSUS) has maximum range to hear a submarine (hundreds or even thousands of miles).

This is where large whales (such as the Blue Whale) go when they want to communicate over long distances.

There are only two tactical advantages of being able to go deeper.

Battle damage. Increased hull strength means that it takes a larger warhead to damage a submarine enough to destroy it or force it to surface. That’s easy to counter, by modifying the torpedo.

Larger operational envelope. Depth affects safe operational depth. The reason is mechanical. If the submarine experiences a failure in the control surfaces, it will either be a “jam dive” (the planes are stuck in the full-dive position) or “jam surface” (the planes are stuck in the full rise position). If the submarine is going fast and deep, there’s no time to react and prevent the submarine from exceeding crush depth. If the submarine is going fast while shallow, a jam rise is almost as bad, because you could broach uncontrollably. When doing testing in the ‘50s, a submarine that did that ended up in an uncontrolled dive after broaching.

As far as going deeper to avoid weapons, when Russia introduced subs in the 70's that could go deeper than existing weapons, an improved torpedo was introduced that could go faster and deeper. It's a lot easier to redesign the mobile weapon than the submarine. Not to mention your deeper diving submarine is going to be slower and have less chance of avoiding the torpedo. A torpedo that is now hunting you in better acoustic conditions then the shallows provide and has a better chance of finding you.

Fireflair wrote:You clearly don't understand modern submarines and both their ability to avoid detection and detection technology. There is nothing gained at 5000m that isn't there at 800m when it comes to avoiding detection. Submarines actually prefer being at a few hundred meters.

And we're still back to the idea of avoiding detection in the shallows. You can't go to 5000m costal. If you're firing missiles, you have to be relatively shallow, so depth doesn't help.

There are no thermal layers below several hundred feet. Thermal layers are caused by surface heating, wave, and wind action. Below that, the water cools very slowly. There are some instances of warmer water very deep, but there are no sudden changes, which is what’s needed to form a layer useful for a submarine to hide in.

The hiding place is called a shadow zone. That location is below the MAXIMUM sound speed. At relatively shallow depths, maximum sound velocity coincides with MAXIMUM water temperature.

At deeper depths, pressure begins to control sound velocity. Eventually, the sound velocity will equal the shallow layer sound velocity. At that point, sound is refracted back up to the layer depth, where it is refracted down again. This area is called the Deep Sound Channel (DSC) or SOFAR Channel (Sound Fixing Or Ranging)

Essentially, the SOFAR is where a hiding submarine does NOT want to be. Any sensor at that depth (submarine, towed array, VDS, SOSUS) has maximum range to hear a submarine (hundreds or even thousands of miles).

This is where large whales (such as the Blue Whale) go when they want to communicate over long distances.

There are only two tactical advantages of being able to go deeper.

Battle damage. Increased hull strength means that it takes a larger warhead to damage a submarine enough to destroy it or force it to surface. That’s easy to counter, by modifying the torpedo.

Larger operational envelope. Depth affects safe operational depth. The reason is mechanical. If the submarine experiences a failure in the control surfaces, it will either be a “jam dive” (the planes are stuck in the full-dive position) or “jam surface” (the planes are stuck in the full rise position). If the submarine is going fast and deep, there’s no time to react and prevent the submarine from exceeding crush depth. If the submarine is going fast while shallow, a jam rise is almost as bad, because you could broach uncontrollably. When doing testing in the ‘50s, a submarine that did that ended up in an uncontrolled dive after broaching.

As far as going deeper to avoid weapons, when Russia introduced subs in the 70's that could go deeper than existing weapons, an improved torpedo was introduced that could go faster and deeper. It's a lot easier to redesign the mobile weapon than the submarine. Not to mention your deeper diving submarine is going to be slower and have less chance of avoiding the torpedo. A torpedo that is now hunting you in better acoustic conditions then the shallows provide and has a better chance of finding you.

Thank you for the explaination of the SOFAR channel.

I would point out that for lattitudes above 60 degrees (sub arctic regions), the SOFAR channel extends to the surface. Subs operating in the Arctic have to contend with this enhanced sound propgation. Intropical zones, the SOFAR channel is at about 1 km depth.

It should be pointed out that for satellyte and aircraft that use either optical sensors to see into the ocean or high resolution RADAR or LIDAR to measure surface disturbances are more likely to detect a submarine at shallow depth than at deep depth.

Subarines benefit from being able to dive deeper, but up to a point at which increased depth becomes a disadvantage. It is a tactical and engineering tradeoff.