A Russian Navy “Grisha-III” in 1997.
Wikimedia Commons
With the late August launch of Marichka – an 18-foot drone submarine prototype – the Ukrainian Navy could soon field an underwater attack capability. Equipped with explosives and controlled by an internal inertial system, the underwater drones could wreak havoc on what remains of the Russian Navy’s Black Sea Fleet.
Since the Black Sea Fleet cannot receive reinforcements – Turkey controls the Bosphorus and does not allow warships through – it must make do with the forces it already has while figuring out ways to intercept a possible future fleet of Ukrainian drone submarines.
That means the fleet’s sonar-equipped Kamov Ka-27 helicopters, as well as the 181st Anti-Submarine Ship Division. The department oversees four Project 22160 and three Grisha III submarine corvettes.
The newer, 1,700-ton Project 22160s apparently lack sonars: their role is to monitor the older, 1,000-ton Grisha-IIIs, which are equipped with two sonars: one mounted under the bow and another – the classic Elk Tail – the ship descends vertically on a long cable.
The Grisha-IIIs are around 40 years old, so it’s worth questioning their condition. But in their day they were “tough little fighters,” according to famed naval analyst Norman Polmar, writing in Proceedings, the U.S. Navy’s journal, in 1976.
If the Black Sea Fleet can deploy its Kamovs and Grisha-IIIs the way the Soviet Navy did, perhaps it can find and sink Ukraine’s drone submarines before they run into a fleet anchorage.
Soviet shallow-water ASW tactics were quite sophisticated, as naval consultant Troy Bentz explained in a 2010 issue of Proceedings. “The Soviets relied on active sonar as the preferred method of tracking in coastal areas,” Bentz wrote. “They learned that sonar dipping – lowering a sonar transducer from an ASW helicopter – is very valuable on fast platforms.”
“Using two or three platforms in one system was the most tactically effective,” Bentz continued. “The Soviets used diving sonar not only on helicopters, but also on the Grisha-class ASW corvettes.” Any mix of two or three Kamovs or Grishas would be sufficient.
The corvettes and helicopters worked together using “leap-frog” tactics, Bentz explained. “One ship was actively drifting and pinging with the sinking sonar, while another was racing toward a calculated position.” In this way, pairs of helicopters or corvettes could drag a kind of sonar chain over a maritime bottleneck – for example, the mouth of a bay.
If there was a flaw in the tactics, it was that the Kamov or Grisha were hovering or standing still while dipping their elk-tail sonar. Any sinking sonar was a stationary obstacle – one that a careful submarine commander could avoid.
The Soviets had foreseen this problem. A Grisha’s bow sonar beeps continuously while the corvette is underway. In a sufficiently large Soviet ASW flotilla, some of the corvettes could sweep while others submerged.
The flaw with this tactic is that behind a bow sonar there is usually a dead spot where the ship’s propellers are located. In 1977, the Royal Navy submarine HMS Swiftsure took advantage of this empty space at the stern to infiltrate a Soviet battle group and spend hours beneath the then-new aircraft carrier Kiev. The result was an intelligence bonanza.
All in all, the Soviets had a method of coastal anti-submarine warfare that was effective but not perfect. If the Russians can copy this tactic, they could have a chance of intercepting future attacks by Ukrainian drone submarines.
Emphasis on power.
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