France 2030 Seabed Control Plan is 21st Century Version of the Atlantic Wall

France has unveiled new “Seabed Control” where they will have drones, mines, submarines and missile platforms to fortify their coastal defenses out to the bottom of the ocean.

This is somewhat like a 21st version of the Atlantic Wall or the Maginot Line. However, the new plan and having military vehicles that can go all the way to the seabed is useful. Submarines tend to not go below 500 meters in depth while the ocean bottom averages about 4250 meters deep.

Vehicles or devices that operate on the ocean floor will be very hard to detect. Think about the years and decades it takes to find wrecks on the bottom of the ocean. Small submarines and drones have already reached the bottom of the ocean.

Here is seafloor map of the Atlantic Ocean. There is all kinds of rough terrain.

The English channel / Straits of Dover are only about 50 meters deep. The seabed becomes really interesting new territory for military use when it is 500 meters or deeper and has rocky terrain or coral or other features. Basalt rock makes sonar and magnetic surveying very difficult. At less than 500 meters or with smooth sand, a drone or new mobile mine could dig in below the sand and hide.

The Atlantic Wall and Maginot Line were on top of the land sitting along the coastline or along a border. They were bunkers and guns built into the rock that could be bombed from the air or pounded by naval guns.

Holding the ocean bottom with enough force would mean that no ships or submarines would be able to operate safely above them. An attacking military would have to have its own ocean crawling force. They would have to come forward on the ocean floor hiding among jagged rocks and the equivalent of mountains and other ocean bottom terrain. The attacking force would take out the ocean floor defenders and defenses and allow submarines to then safely operate.

Ocean bottom terrain is somewhat like operating in the mountains. Mountain forces can hide from attacks using hundreds of meters of rock.

The French Navy already has mine warfare and hydro-oceanography capabilities contributing to the control of the seabed. France will expand capacities down to 6,000 meters deep with deep-sea exploratory military capacities. They will use underwater drones (AUV – Autonomous underwater vehicle) and robots ( ROV – Remotely operated vehicle).

Some of France’s new plans are:
Study the particular modes of ultra-low frequency acoustic propagation.
Increase our undersea search, surveillance and intervention capabilities to meet the needs inherent in maintaining freedom of action for French forces in areas with depths down to 6,000 meters.
Continue to analyze ways of deploying underwater surveillance vehicles in order to broaden the range of military options: air-portability, combat ships, submarines, etc.
Make CEPHISMER a center of expertise capable of implementing a military capability complementary to SLAMF for depths greater than 300 meters.

China the UK are also working on seabed defense systems.

Today’s submarines are link blimps in the ocean. They float high over the seafloor. Dr Robert Ballard proposed submarines that hide on the ocean floor.

Modern nuclear attack submarines like the American Seawolf-class are estimated to have a test depth of 490 meters (1,600 ft), which would imply a collapse depth of 730 meters (2,400 ft). Each 10 meters (33 feet) of depth puts another atmosphere (14.7 psi/100 kPa) of pressure on the hull.

There is a lot of sonar and magnetic interference on the ocean floor. It can be very hard to find something hiding in the seafloor terrain.

The average ocean depth is 4250 meters (2.6 miles).

300 meters (1,000 feet): the hull is withstanding thirty atmospheres (30 bar, 441 psi, 3,000 kPa) of water pressure.
800 meters: the hull is withstanding eighty atmospheres (80 bar, 1176 psi, 8,000 kPa) of water pressure.
3000 meters: hull is withstanding three hundred atmospheres (300 bar, 4410 psi, 30,000 kPa) of water pressure.
6000 meters: hull is withstanding six hundred atmospheres (600 bar, 8820 psi, 60,000 kPa) of water pressure.

SOURCES – Naval News
Written By Brian Wang,

30 thoughts on “France 2030 Seabed Control Plan is 21st Century Version of the Atlantic Wall”

  1. Likely anticipating the coming Facebook proxy war, masquerading as the Napoleonic War, Part Deux, when they come for your data.

  2. Seems like sensors and a nearby quick reaction force would be good enough. Wasn't there a 'listening line' of microphones checking for submarines decades ago – SOSUS or something — still used in some ways…

  3. Greece is a good example of this. The Greeks won a number of what could be called defensive victories against the Persians at Salamis and Marathon. Those victories saved Greece from Persian conquest, but they did not end Persian attacks on Greece. In fact war between the two countries went off and on for decades afterwards. Ultimately, it wasn't until Alexander invaded and crushed the Persian Empire a century later that Greece was spared from further Persian aggression.

  4. The USSR began attacking the Germans even during the first days of Operation Barbarossa in June 41. Like any army, the Soviets alternated between defense and offense as the tactical and strategic situation dictated. In fact, they launched a number of major offensives in 1941 and 1942 that the Germans crushed. The most well known is the 2nd Battle of Kharhov in May 1942 where after initial gains by Soviet forces the German Army Group South encircled and destroyed several Soviet Armies.

    Even when the Soviets assumed the strategic offensive in 1943 they were beaten a number of times by the Germans. Again at Karkhov in March 1943, on the Moscow Front in late 43, at Narva in 44, most famously and lopsidedly at Targu Frumos in 44, and in Courland in 45. The German Army was by no means broken when the Soviets took the strategic offensive. The same was true of the Japanese when the US took the strategic defensive at Guadalcanal in Aug 42. The Japanese were full of fight even up to the invasion of Okinawa in 45.

    I think what is confusing you is that regardless at whether a country fights battles on the defense, ultimately throughout history no country has won a war solely on the strategic defensive. In every case, the victor had to assume the offensive and take the battle to the enemy.

  5. too long. constant maintenance, weather, fishing boats… take decades. Billions, and be porous and unmanageable…

  6. Truly bizarre.
    Though timely and forward-thinking?
    As the intimate locations and identifications of all things military, terrorist, political, and technical become observable from above and sensed from around, the last great hiding spot of military assets appears to be underwater/ ground. Sensing and quantifying these threats may be crucial over the next few decades…

  7. Pretty sure Afghanistan poked a nuclear porcupine, so it is a little complicated. However, I have seen that the point I was trying to make is clearer with two examples. "best defense is good retaliatory offense" "Best defense is good aggressive offense". There are bozos out there who will see the second and think it is a good idea, as they can say they are just being defensive. I am trying to separate "offense" from "aggression". Offense is a type of fighting, not *always* aggressive. Defense seems pretty, well, defensive, but would not include sending out assassins or such. Ahem.

  8. If you've got a credible nuclear deterrent, it doesn't really matter if you've got thousands of warheads, like Reagan and Gorbachev had, 300 odd like China, or half a dozen like Kim. An all-out conventional war could probably do as much damage, eventually, even when the protagonists are as mismatched as the US and Afghanistan, but poking a nuclear porcupine brings instant regrets.

  9. I'm intrigued as to what enemy France in concerned about might attack them from the sea.

    The English and the USA (again)?

  10. Historically speaking, no power has ever won a war on the defense.

    I think you could argue that the USSR won WW2 on the defense.

    Eventually they went on the offensive, but they'd broken the German army by then, through effective defense.

  11. Not to disagree on that, indeed Hitler had already become the aggressor so the French even if they had attacked would not be. More of a broad concept that some these days would twist that saying into something stupid like: Because the best defense is a good offense, our offense was defensive.

  12. Those that see that as aggression aren't thinking clearly. Consider this, the French could have stopped Hitler in 1938, but their people overwhelmingly did not want to fight. The end result was a war that killed millions. Had the French crushed Hitler in 38, all those lives would have been saved.

    The reality is that people are short sighted and selfish. Their failure to consider the long term consequences of their actions constantly doom them to disaster. Munich 38 is a good example. The French didn't want to die in 38 for the Czechs, They didn't want to die in 39 for the Poles. What was the end result of the thinking? Over 200,000 of their soldiers died in 1940 anyway. And then they were under the German jackboot for 4 years and thousands more were killed. As the old saying goes, a stitch in time saves nine. Or in Europe's case, crushing Hitler in 38 would have prevented the deaths of millions of people.

  13. How about, "the best defense is a good retaliatory offense"? These days, many would see the other version as simply supporting the aggressor.

  14. Then just a year later the Germans invaded Poland in Sept 1939. Again, the French cowered behind the Maginot Line and did nothing. While their entire army sat motionless, the Germans overran Poland, then they redeployed their forces to their western border. Nine months later, they crushed the Western Allies in just 6 weeks.

    Historically speaking, no power has ever won a war on the defense. As the saying goes, the best defense is a good offense. The French Army would have much better served building a mobile army based on tanks, motorized infantry and artillery, supported by their air force. Had they done that they could have organized an elastic defense with fast moving, mobile tank forces to seal any breaches the Germans created. As it was, once the Heinz Guderian's 3 panzer divisions smashed thru French defenses at Sedan, the battle was as good as over.

  15. As a US Marine I've studied the Maginot Line extensively, as well as the German invasion of France in 1940. I would offer that there are major problems with extending it. One, the cost of extending the line all the way to the sea would have been tremendous. Two, the cost to maintain the entire line would eat up a major part of the French Defense budget. Three, those expenditures decrease the amount of money they could spend on other things like their air force and their armored forces. Four, the line actually was not that effective. The Germans were able to seize parts of it when they wanted. I can give examples if needed, Five, the main weakness of any linear defense, even a fortified one, is that all you have to do is pierce it in one place. Once you've breached the line, the whole thing becomes useless.

    The Maginot Line had other serious consequences that ultimately doomed France. One, it basically doomed the Czechs and the Poles to destruction. By building the line, the French committed themselves to the Strategic Defensive. And thus when the Sudeten Crisis erupted in 1938, the French Army which lacked the will and the offensive capabilities to aid the Czechs. the result was one of the most cowardly political appeasements of all time, the Munich Agreement of 1938.

  16. The ocean being relatively unknown is a visibility issue. Though with IoT hardware and Slocum glider AUV's starting to be built in bulk, there is a bit more visibility (though limited due to the power budget of a glider type AUV as they typically use trickle charging and paraffin thermal energy storage batteries). There's been a surge in chinese knockoff Slocum gliders being found in the south china sea region.

    With armed large format UUV's (XLUUV) being actively prototyped, as well as new patrol USV ships (sail equipped surveillance ones like SailDrones, converted small boats with remote weapons systems bolted on, and trimarans with dipping sonar like the ACTUV), we are probably going to see interesting swarm tactics.

    Additionally, many submarine navies have an existential fear of the ocean suddenly becoming transparent in terms of surveillance, due to the onset of things like water penetrating LIDAR. Green laser LIDAR appears to be already being used from airplanes for shallow water seafloor mapping. SSBN subs have held an advantage in the nuclear triad due to their ability to disappear into the black hole that is the deep ocean, but that ability being nullified will put a lot of pressure on rebalancing the triad.

  17. The first thing that came on my mind, when I heard that there were Russian military exercises near Ireland was – where are Transatlantic internet cables located. Russians could cut the cables or drop a bomb on them or something and cripple communciations between USa, Europe,…
    So it is naturally that should be protected, although I doubt it is practically possible. They are too long. Starlink satellites are much harder for Russians to take down at least for now.

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