Thursday, September 8, 2016

ASW: abundans cautela non nocet

ASW: abundans cautela non nocet
// USNI Blog

maxresdefaultI was lucky, I was a JO in the last act in the Anti-Submarine Warfare golden age; the Cold War. Headed over to Desert Storm as an Ensign, came back a LTjg and then spent a few glorious years in an ocean where Soviet Tangos and Victor IIIs still prowled, frustrated, and more often than not – snuck by us when we weren't trying to run away from them.

In exercises towards the end of that first sea tour a few years after the Soviet collapse, we still were a well oiled machine living off of tactical inertia. I have one of those memories at sea that at the moment you knew you'd always remember; a clear, bright evening. RED submarine was, I believe USS GATO (SSN 615). In the distance there were two SH-3 dipping one after another as a P-3 flew in orbits a few hundred feet above them throwing out flares/smokes on occasion while for the DD & FFG, tails were wet and working the same sub.

What made it so memorable wasn't just the visual beauty of it all, but was that everyone seemed to be able to locate, track, and even make simulated attacks. It wasn't that easy. It was never that easy – but at that one moment in time it all came together and had a bit of a non-goat-rope feel about it. Though you hoped that is what it would be like with a no-kidding adversary submarine – whichever nation they came from now that the Soviet Union was gone – but you knew that it wouldn't. You remember the message traffic that outlined that TANGO disappeared when they wanted to, and that Angel of Death VICTOR III – well, people were still collecting jock-straps from Bear Island to the Malta Escarpment.

Surface, submarine, and aviation – everyone was in on the game. Carriers had large numbers of escorts when they deployed – and for the time almost all of them were ASW capable themselves for a knife fight, and the FFG, DD, and CG came with a mix of the last of the SH-2 and the sparkly new SH-60 to reach out a bit. The carriers had the S-3 and the SH-3 with the SH-60 coming along there as well. The submarines, well, say no more. Ashore, you always had the P-3 bubbas for comic relief.

The hope was that somewhere in that mix was the key to keep the submarines away, if not dead. We were never happy with the one trick pony of the LWT – after they took away our DUSTBIN – but if nothing else it might be good enough to make a hostile submarine break contact.

But, then the post-Cold War mindset came in. ASW went to the back and the money went elsewhere right when the potential enemy submarines were getting much better – our ASW technology was only getting marginally better, and our ASW skill against non-permissive and non-scripted submarines drifted and faded in the ambient noise of higher priorities.

As, rightfully, much of our ASW discussions should only take place behind the cipher door, it's helpful to find something in open source as a reference point. In The Economist last month, there is a great article on modern ASW challenges, Seek, but shall ye find?

Some nice points to ponder a couple decades post-drift;

DURING war games played off the coast of Florida last year, a nuclear-powered French attack submarine, Saphir, eluded America's sub-hunting aircraft and vessels with enough stealth to sink (fictitiously) a newly overhauled American aircraft-carrier, Theodore Roosevelt, and most of her escort. An account of the drill on a French defence-ministry website was promptly deleted, but too late for it to go unnoticed.

Nor was this French victory a fluke. In 2006, in what was very far from being a war game, a Chinese diesel-electric submarine surfaced near Okinawa within torpedo range of another American carrier, Kitty Hawk, without having been detected by that carrier's escort of more than a dozen vessels and anti-submarine aircraft. And, from the point of view of carrier-deploying navies, things are threatening to get worse. Saphir, launched in 1981, hardly represents the state of the art in underwater undetectability; in the decade since the Okinawa incident diesel-electrics have become even quieter. For an inkling of the silence of the new generation of such subs when they are running on battery power alone, without their engines turning, Jerry Hendrix, a former anti-submarine operations officer on the Theodore Roosevelt, asks: "How loud is your flashlight?"

The always quotable Jerry!

…submarines are spreading. Since the cold war ended, the number of countries deploying them has risen from a dozen or so to about 40.

While we have rested some, tinkered with "new" ASW search methods a bit, the world continues to build.

Worse, for those trying to defend ships from submarine attack, Western powers have routinely cut anti-submarine spending since the end of the cold war. American carriers retired the S-3 Viking submarine-hunting warplane in 2009, leaving shorter-range helicopters to compensate. Since the Soviet Union's demise the average surface escort of an American carrier has shrunk from six vessels to four. … Many carry anti-ship guided missiles as well as torpedoes. One such, the CM-708 UNB, was shown off by China in April. It packs a 155kg warhead and, after popping out of the water, flies at near the speed of sound for about 290km. An export version is available but, if you prefer, Russia's submarine-launched Kalibr-PL missile offers a bigger warhead and a terminal sprint at Mach three.

So, solutions? We need to be careful in putting too much trust in high-demand, low-density "war winning" capabilities yet to be robustly tested (and always remember, no one has really faced a sub threat since the Royal Navy in the early 1980s), or promises of something just around the corner – we should reinforce what we know works.

Keeping track of submarines is good to remove uncertainty in peace, and a quicker kill in the transition to war – but how do you try to recreate the Cold War multilayered tracking system? Well, we don't have the numbers or the money – so we'll experiment a bit.

We are thinking about drones, but their utility starts to wear thin after the second follow-on question – but they have great promise not as a solution – but a tool;

Perhaps belatedly, but certainly determinedly, a new approach to the submarine threat is now being developed. It is based on a simple principle: since submarines are hard to detect, when you do find one you should never let go.

Shadowing threatening submersibles is nothing new. Trailing something is a much easier sensory task than discovering it in the first place, when you have an entire ocean to search. But at the moment this job is done by destroyers and (for those that have them) nuclear submarines. These cost billions of dollars to build and tens of millions a year more to run. Instead, the idea is to use smallish unmanned ships—marine drones, in effect—to do the job. These will be packed with enough sensors and artificial intelligence to follow adversaries' submarines automatically.

Half a dozen Western naval powers are conducting the R&D needed to build these, according to Eric Wertheim, author of the US Naval Institute's reference doorstop "Combat Fleets of the World". America is furthest along. In June its Office of Naval Research and its Defence Advanced Research Projects Agency, DARPA, began tests in the Pacific of the Sea Hunter, an unmanned (and, for now, unarmed) 40-metre trimaran, pictured. It is designed to follow an enemy submarine from the surface relentlessly for months, even in high seas. While the crew of the boat being tailed will probably be able to hear their pursuer's diesel engine, that is not really a problem. Short of a torpedo launch, which would be an act of war, "there's nothing you can do about it", says Nevin Carr, a retired rear admiral in the American navy who now works at Leidos, the firm which designed Sea Hunter.

ASW is not that easy. The water column is not constant, busy sea lanes are loud, the ocean bottom can be fussy – and your target gets a vote and the right to have countermeasures.

Saab Kockums's new 62-metre A26 model will sport a tube from which an underwater drone could slip out to attack surface drones. This, Mr Wieslander says, is the first time that such a feature has been fitted to a production submarine. Mr Krepinevich, however, counsels caution regarding underwater drones. They are fine for attacking other drones, but without huge advances in battery technology (see article), no such machine could keep up for long with a big submarine that charges its batteries from a diesel engine and can travel at up to 20 knots—much less with a faster nuclear-powered one.

More sophisticated systems than this are in the works—including anti-drone countermeasures. According to Torstein Olsmo Sæbo, a scientist at FFI, Norway's defence-research establishment, drone-towed acoustic arrays can now mimic the signature of a big submarine, luring a drone off in the wrong direction.

A new IUSS?

One way to do this, at least for home waters, is to have a dense grid of fixed detectors. One of the more advanced of these is Singapore's. It consists of underwaterbuoys called acoustic nodes that are tethered to the sea bed two or three kilometres apart. These nodes can talk to each other. They communicate by broadcasting precisely calibrated vibrations through the water. At the moment they are sending test messages, but eventually they will be equipped with their own submarine-detecting sensors.

Active and passive? Huh … wait unit the whale people find out about that active part.

Anyway, we have been here before;

The arms race between surface vessels and submarines has been going on for almost exactly a century—since Germany's demonstration to its enemies in the first world war of the threat from its U-boats. By the end of the second world war, the Allies had become so good at finding U-boats that German crews taking to the sea had a life expectancy of about a week. As the examples of the Kitty Hawk and the Theodore Roosevelt show, the balance at the moment has tipped back in favour of the submariner. The great question is how long it will stay that way.

The key in the hyper-Darwinian game that is ASW is to never stop. Never stop developing, never stop training, never stop understanding the threat.

Another lesson of real-world ASW? It takes numbers of ASW units on, above, and under the surface, a wide diversity of units, and the investment to maintain them.

As for the kill-chain part of the problem, well … ahem. Let's not go there right now.


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