Anti-submarine warfare is an issue of increasing concern among NATO allies, as the Russian Navy has not only demonstrated a more aggressive stature throughout the Baltic Sea and Atlantic Ocean in recent months, but has made some particularly concerning claims about the training they’ve been conducting. Now, seven surface combatant vessels and three sub-hunting aircraft hailing from multiple NATO allied Navies are on the hunt for two of their own submarines in the deep waters of the Atlantic, off the coast of Norway.

The annual drill, which began last week, will pit the two subs against the best NATO has to offer in terms of tracking and intercepting advanced submarines, providing both surface and submerged crews with valuable experience pursuing enemy submarines, or evading enemy intercept, respectively. Assets from Denmark, France, Germany, the Netherlands, Norway, Spain, Turkey and the U.S. will all participate.

“This exercise is a unique opportunity to enhance naval forces’ warfighting skills in all three dimensions of Anti-Submarine-Warfare in a multinational and multi-threat environment. We are most grateful to Norway and the Norwegian Navy for offering to host our exercise,” Rear Admiral Andrew Lennon, NATO Submarines Commander, said in a news release provided by NATO’s Allied Maritime Command.

The drill will provide the opportunity for each of the seven surface ships to devise and execute a variety of strategies and tactics aimed at tracking down the encroaching subs, who (based on releases regarding previous drills of this nature) will likely be given orders to traverse the training area with a specific target in mind. The surface ships will have their pursuit bolstered by maritime aircraft specialized in submarine hunting. Those eyes in the sky may prove invaluable to tracking down signs of submarine behavior deep beneath the surface of the ocean, but in the depths of the North Atlantic, even airborne assets are no guarantee of victory.

“This valuable training opportunity will allow us, in conjunction with our NATO allies and partners, to enhance our ASW capabilities, improve interoperability and ultimately strengthen the alliances that bind our nations together in mutual commitment to regional security,” Cmdr. Chad Donnelly, commanding officer of Patrol Squadron (VP) 10, said in a Navy statement.

Some have described these sorts of drills as a game of “cat and mouse,” though that may not be the most appropriate comparison. While the two submarines will face the challenge of traversing the Atlantic with seven warships and three aircraft on their tale, those warships will also have to engage in the hunt without falling prey to the submarines themselves. The “mice” in this hunt have the advantage in a number of ways, and although outnumbered, could potentially even the odds by “sinking” a surface ship or two as they make their way across the training space.

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If you think it’s unlikely that a submarine could successfully evade detection long enough to do so in today’s technological climate, a similar drill from 2005 may surprise you. In that drill, the Nimitz Class aircraft carrier USS Ronald Reagan and it’s accompanying strike group lost out to a single diesel powered Swedish submarine — the Gotland. Although most diesel subs are fairly easy to track thanks to their reliance on oxygen forcing them to surface after only a few days, the Gotland utilizes liquid oxygen, allowing it to remain submerged for longer periods of time, and ultimately to “run rings around” U.S. Navy forces — according to Naval analyst Norman Polmar. The liquid oxygen-diesel set up actually ends up running quieter than nuclear submarines that have to utilize cooling pumps in their reactors.

The Swede’s success proved so dramatic that the U.S. Navy then leased the Gotland for two years just to develop systems that could effectively counter the stealthy submarines capabilities.

Russia currently operates 72 submarines of varying types and propulsion systems (one more than the United States Navy at the moment). In March, they claimed to have traversed the Atlantic undetected and parked nuclear attack subs outside of multiple U.S. Navy bases along the American east coast, though the Department of Defense has not issued any response pertaining to their claims. They have, however, announced that the United States will bring back the Navy’s Second Fleet, tasked specifically with countering Russian aggression in the Atlantic — seeming to suggest that there may be some truth to Russia’s claims.

Featured image: The Los Angeles-class attack submarine USS Houston (SSN 713) leads a formation of ships from USS George Washington (CVN 73) Carrier Strike Group and Japan Maritime Self-Defense Force (JMSDF) for a photo exercise during the final day of Exercise Keen Sword 2011. The exercise enhances the Japan-U.S. alliance which remains a key strategic relationship in the Northeast Asia Pacific region. Keen Sword caps the 50th anniversary of the Japan – U.S. alliance as an “alliance of equals.” | U.S. Navy photo by Mass Communication Specialist 3rd Class Adam K. Thomas/Released