RAN's Collins class replacement

[Officer of Engineers]

You're talking about passive sonar, not active. There is zero defence against pinging. The only downside to pinging is that from a distance, the sub will know where you are before you know where they are. The old axiom of warfare, find the enemy. Kill the enemy. Why do you think Soviet destroyers pinged the hell out of their naval bases before their SSBNs go on patrol? Your only chance against pinging is to get the hell out of the way.

However, from the Chinese POV about choke points, that's fine and dandy. Their pinging would keep Australian subs out of their area.

As for the old Ming, we were not actively pinging. Why would we? It's normal transit and pinging does disaster to the local plant life and wild life. It wrecks entire schools of fish. Even the Soviets only ping the hell out of their area during SSBN transits.

There's a big downside to hypersonic missiles vs subsonic AShM. Subsonic AShM can hug the sea surface. Hypersonic missiles can't, meaning they can be detected a lot further away than subsonic missiles. Normally, you would try to limit the reaction time with speed but the advent of fast CPUs, defences would be up before they can reach their targets. Sea hugging missiles have the advantage of being a lot closer before detection and can at least spray shrapnel onto their targets.

[zraver]

Sir, about active.... Hull shaping can defeat it. That appears to be why the Astute class is shaped the way it is.

[Gun Grape]

It doesn't defeat it, It reduces the return signal. Just like Anechoic tiles.

[zraver]

Like stealth shaping it radically reduces the return signature. Although its directional (generally against surface active sonars) it doesn't compress with depth and lose its capabilities like anechoic. tiles do. Combined with the natural noise of the see, thermoclines, anechoic tiles, and sound silencing, and if all else fails the ability to out run surface warships and often out maneuver torpedoes the next generation of subs will be ghosts in the water until a new technology emerges. If your surface/air ASW active sonars can only pick it up from say 2000m, but it can hear you from 40km, and kill you from 30km, and strike your shore targets from 500km..... Even the rumor a modern nuke boat is in the region may dissuade adventurism.

[Officer of Engineers]

Ok, let's put it this way. Would an Australian SSN Captain know where the Chinese naval task force doing active pinging is? Yes. Would he know it before the Chinese know where he is? Yes. Is he stupid enough to take on an entire Chinese naval task force doing active pinging all by himself? Not a chance in hell.

[Monash]

Ok, let's put it this way. Would an Australian SSN Captain know where the Chinese naval task force doing active pinging is? Yes. Would he know it before the Chinese know where he is? Yes. Is he stupid enough to take on an entire Chinese naval task force doing active pinging all by himself? Not a chance in hell.

Hmmm.. this is one scenario where a screen of automated drones deployed well ahead of SSNs could be very useful. All the drones have to do is detect active pinging, ID their type/source, count them and then get bearing & speed measurements etc. They don't even have to have the best sensor tech available just stuff good enough to handle active sonar detection at reasonable ranges. Once they've done that they either pop to the surface or release a transmitter buoy and send the data home for relay back to the SSNs.

Even if the enemy knows they're there he still has a dilemma. He can't actively search for enemy submarines without giving away his location and if he doesn't use active detection the SSNs can sneak up on him.

[Gun Grape]

Even if the enemy knows they're there he still has a dilemma. He can't actively search for enemy submarines without giving away his location and if he doesn't use active detection the SSNs can sneak up on him.

It would help, But the Chinese have helos with dipping sonar and ASW fixed wing (KQ-200) and their ships have towed array systems.

So like the US and other allied navies, they can bang away miles away from the friendly ship. Not sure if they have a version of the RUM-139 (Modern conventional armed ASROC)

Find, Fix and Destroy at long range

[zraver]

According to Aaron at Sub Brief his boats were never counter detected by surface or air ASW platforms. Even when they had to stay in a designated area to give the ASW assets a chance. This is backed up by the USN's inability to keep the Gotland from racking up "kills" against US carriers (photos taken from inside the ASW screen via the periscope). Modern subs are very quiet, even at speed. I already posted the source that says the Virginia is as quiet at 20 knots as a 688 is pier side and Aaron was in 688's. Unless the Chinese are radically better that we are they have a problem with subs just like we do. BTW, he also says sonar can hear helos and fixed wing aircraft. During the Cold War, as much better at passive as we were than the Soviets, collisions at (under) sea still happened.

In a high tension scenario, the thought of a allied nuke boat or a modern JMSDF Soryu class DE/AIPB is going to give Chinese Admirals in charge of carrier strike groups fits. The sub can hear them from farther than they can see the sub. The farther out they push the screen to try and hold off ranges for stand off weapons the easier it is to penetrate. The tighter the screen, the closer the sub can get before having to try and penetrate.

I don't know for sure but I am guessing a carrier doing air ops really messes with ASW efforts. Carriers have too go fast to help their planes generate lift. This makes it hard to drift/sprint/drift for the escorts making airborne ASW the primary defender of the fleet. The sonars (passive and active) on helos are tiny in both listening area and transmitting power. Fixed wing can add sonobouys, but only so many can be deployed, and the farther from the coast they are, the less land based support they can call on. Undersea sonar systems can create lines that might hear a sub cross over, but it will be hard to do any type of real time tracking.

Also, once again for the Virginias, SeaWolfs, 688 flight III, Yasen-M's, Oscar II's it only takes one to cripple a fleet since they are no longer really SSN's but are in truth SSGN's via VLS systems. Once the USN's anti-ship missile tech catches up this threat goes exponential.

[Monash]

It would help, But the Chinese have helos with dipping sonar and ASW fixed wing (KQ-200) and their ships have towed array systems.

So like the US and other allied navies, they can bang away miles away from the friendly ship. Not sure if they have a version of the RUM-139 (Modern conventional armed ASROC)

Find, Fix and Destroy at long range

As I recall the RUM 119, like its predecessor isn't exactly 'long range'. I don't know what the range is of the submarine launched version of current gen Harpoon missiles is but its got to be a dammed sight longer than the 30 plus kicks you get from a RUM 139 once its dropped the torpedo.

I'd always thought fixed wing and helo dropped torps were the primary line of defense against enemy subs.

[Officer of Engineers]

Even if the enemy knows they're there he still has a dilemma. He can't actively search for enemy submarines without giving away his location and if he doesn't use active detection the SSNs can sneak up on him.

Numbers game. A Chinese naval task force is at least 4 destroyers (The VARYAG/LIAONING CBG is 2 cruisers, 4 destroyers, 1 replinishment ship as well as the aircraft carrier). Kill one (actuially just firing a torpedo which must travel faster than 4 knots) and the other 3 will know where and how to kill you. Trading destroyers for SSNs is not a game winning strategy.

Jason says SSN is a force multipler. He's right. For that, you need a force. Not a lone lion.

[zraver]

As I recall RUM 119, like its predecessor isn't exactly 'long range'. I don't know what the range is of the submarine launched version of current gen Harpoon missiles is but its got to be a dammed sight longer than the 30 plus kicks you get from a RUM 139 once its dropped the torpedo.

I'd always thought fixed wing and helo dropped torps were the primary line of defense against enemy subs.

Air dropped torpedoes tend to be electric and run out of oomph quickly. LI batteries promise to change this when they are introduced but for now, once an electric torpedo uses up half its battery performance falls on its face. The big thermal torpedoes have ranges now exceeding 30km.

OOE, 4 destroyers is not enough since half or more have to be sprinting at any one time if the carrier is conducting air ops. You have to hope your air can find and at least semi-localize the sub so you can vector the surface units into the area, but aircraft deployed sonar is far less capable. A drifting destroyer with bow and towed area can ping above and below the layer, but can't keep up with the carrier. A destroyer fast enough to keep up with the carrier can't use sonar. The Gotland killed our carriers over and over again.

In the USN, subs are lone lions, have been since early in WWII. The Soviets used wolf packs, but they had missiles that could talk to one another via data link.

[Officer of Engineers]

The VARYAG/LIAONIG is bait. Nothing more.

[Monash]

In the USN, subs are lone lions, have been since early in WWII. The Soviets used wolf packs, but they had missiles that could talk to one another via data link.

So standard doctrine is still that they dont pair up or tripple up to take on a large surface force (thats ssuming the SSNs are close enough to one another to co-ordinate in the first place of course)? I say this because in the South China Sea at least there would seem to be a lot of choke points that would provide you with the opportunity to do so if you wished.

[zraver]

According to Aaron, nope, they work alone. If you are by yourself, then everything is a target, Modern subs pack so much firepower making them fleet killers. Again according to Aaron, you fire 90d off your bearing, if possible from the other side of the layer to mask the sound of the launch and at a decently long range so any counter fire is delayed by how long it takes them to hear the fish coming. This gives you time to move, and they have a huge area to try and decide where to shoot at. A Virginia can engage 2 targets at a time this way, a Seawolf can do 4. Subs shooting at a ship is a 2D problem (bearing and speed) counter fire is 3D, (bearing, speed, depth) and the sub has the advantage in detection, fire power (heavyweight thermal vs lightweight electric) and environment. Ships have air support, and asroc style counter fire can get to the target area quickly, hence the need to fire in a way and at a range that minimizes detection.

[zraver]

Joining twitch and listening to Aaron's sea stories, expose's (non-classified) and naval news is hella informative. Dude was a sonarman who ended up being a sonarman trainer who was assigned to the development squadrons and spent time off the Soviet and Russian coasts. The only surface sonar he was scared of was the Horse Jaw. He is dismissive of most surface and air ASW effectiveness to American boats being targeted with Soviet or American sonars. You will learn about sonar (types and employment), layers, sound channels, the shadow zone, torpedo evasion, life on a nuke boat and a possible impact with a whale.... He also does a series of videos on Patreon called Sub Brief where he does documentaries on various non-US sub classes. He releases them to You Tube after 1 year.