With all the money being spent on new aircraft, smart bombs (and torpedoes), anti-ship and anti-aircraft missile systems you would think the U.S. Navy would pay a lot more attention to the cheap and low-tech weapon that has, since the end of World War II actually damaged or destroyed more U.S. Navy ships than any other type of weapon. This common cause of American warship losses was naval mines. While the American naval budget tends to focus on dealing with high-tech (and expensive) threats that only a handful of wealthy nations can afford, much less is spent to deal with a naval weapon (naval mines) that remain cheap enough so that just about any country (and many Islamic terrorist organizations) can afford them.
A growing number of American naval officers have been trying to get the senior leadership to take this threat seriously and actually do something. That appears to be happening as the availability of cheaper mine-clearing tech makes it difficult to insist that cost is an issue. This cheap tech makes heavy use of unmanned surface and underwater systems that can automatically search and report, to a human operator, about any mines down there. If the human operators confirms the presence of a threat that mine can be destroyed without risk of people getting hurt. The next step is an automated system for dealing with the older mine designs that float near the surface. What makes all this possible is that a lot of the UUV (unmanned underwater vehicle) tech was first developed and heavily used by commercial operations (researchers and offshore oil facilities and exploration). At the same time USV(unmanned surface vehicle) tech was easier to develop and since the late 1990s has been increasingly put to work for commercial and military applications. Now the U.S. Navy is applying its decades old networking tech to a system that would quickly clear mines from a large area.
The latest example of this is the 11 meter (35 foot) USV ARCIMS towing the AQS-24B torpedo like (in appearance) mine-hunting system. The AQS-24 was originally designed to be towed by helicopters at speeds of up to 34 kilometers an hour. The AQS-24B contains a high resolution sonar that seeks out mines than lay on the sea bottom, waiting for ships to pass over. This version can more quickly identify these “bottom mines”, which is important if it is one that is able to detonate if a ship type it was programmed to attack is detected. The U.S. Navy has been using this tedious and time-consuming detection and destruction approach since the 1980s and there have been many changes to make it very reliable and effective.
AQS-24 has been around since 1995 and has been updated several times to incorporate more powerful (and often smaller and cheaper) electronics and other components. AQS-24 was first demonstrated being towed by a USV in 2002. The switch to USVs is now considered because there are small UUVs that can be sent down to destroy the mine by having the UUV explode or drop an explosive that will go off when the UUV is out of the way.
The goal here is to build enough of these UUV systems to put one or more on most surface warships and develop networking software that can be programmed to calculate the quickest way to cooperate and search an area and destroy any mines found. The idea is to make the robotic mine clearing system something that does not require a specialized ship or a lot of highly trained techs to operate.
Something like this is long overdue because modern naval mines were widely used for the first time over a century ago, during the Russo-Japanese war (1904- 1905) and found to be simple, cheap and very effective. These first weapons were contact mines, floating in shallow water and kept in place with an anchor and chain. When the tide was right they would be just below the surface, ready to explode whenever struck by a ship. Some 2,000 of these mines were used to destroy sixteen ships during the Russo-Japanese war. That's one ship lost for every 125 mines used.
During World War I (1914-18), modern mine tactics and clearing methods evolved. Thousands of mines were laid to provide defensive barriers against enemy movement in the North Sea. Mines were also used offensively by secretly placing them across known enemy sea routes. More than 1,000 merchant and war ships were lost because of the 230,000 mines used. That's over 200 mines used for every ship lost.
During World War II there was a major effort to develop better mine clearing methods to deal with an even larger number of mines being used. During World War II a total of 2,665 ships were lost or damaged to 100,000 offensive mines. That's one ship for every 37 mines. Some 208,000 mines were used defensively to inhibit enemy movement and tie up his resources.
Naval mines achieved several striking successes during World War II. In the Pacific naval mines proved more destructive to the Japanese war effort than the atom bombs. During a 10 week period between April and August 1945, 12,000 mines were delivered to the Japanese coast by American bombers. These destroyed 1,250,000 tons of Japanese shipping (670 ships hit, 431 destroyed). That's 18 mines for each ship hit. The Americans had air superiority, so losses during these 1,500 missions amounted to only 15 planes, most of them accidents. Had these missions been flown against opposition, losses would have been between 30 and 60 aircraft, plus similar losses to their fighter escorts. Either way it was a stunning success for naval mines,
A conventional submarine campaign was also waged against Japanese shipping using mines. Comparisons between subs using mines and torpedoes is interesting. A hundred submarines were involved in an anti-shipping campaign that ran for 45 months from December, 1941 to August, 1945. These subs sank some 4.8 million tons of enemy shipping with torpedoes. For every U.S. submarine sailor lost using submarine launched torpedoes, 560 tons of enemy ships were sunk. During the mine campaign 3,500 tons were sunk for each U.S. fatality. On a cost basis the difference was equally stark. Counting the cost of lost mine laying aircraft (B- 29's at $500,000 each) or torpedo armed submarine ($5 million each), we find that each ton of sunk shipping cost six dollars when using mines and fifty-five dollars when using submarines. This data was classified as secret until the 1970s. It indicates that mines might have been more effective than torpedoes, even if the mines were delivered by submarine.
The Germans waged a minelaying campaign off the east coast of the United States between 1942 and 1944. Only 317 mines were used, which sank or damaged 11 ships. This was a ratio of 29 mines used for each ship hit. More importantly eight major ports were closed for a total of 40 days. One port, Charleston, South Carolina, was closed for 16 days, tying up not only merchant shipping but the thousands of men, warships, and aircraft dealing with the situation. American submarines also waged a limited mine campaign in the Pacific. For 658 mines used, 54 ships were sunk or damaged (12 mines per ship). No subs were lost. Considerable Japanese resources were tied up dealing with the mines. On the Palau atoll the port was closed by the mines and not reopened until the war ended. Even surface ships were used to lay mines. Three thousand mines were laid by destroyers. Only 12 ships were hit but these were barrier fields, not the ambush type mine fields that a submarine can create by sneaking into an enemy held area.
Even after World War II, despite all the evidence of naval mine effectiveness, not much chaged. In Korea during the early 1950s, the Soviets provided North Korea with 3,000 mines, many of 1904 vintage. These were used to defend Wonson harbor. It took several weeks for UN forces to clear these, at a loss of a dozen ships hit. Half of these ships were destroyed.
During the Vietnam War over 300,000 American naval mines were used, primarily in rivers. The vast majority were not built as mines but were aerial bombs equipped with magnetic sensors instead of fuzes. These bombs/mines used a small parachute to insure that no damage occurred on landing. In shallow water these makeshift weapons sat on the bottom and performed as well as mines. Haiphong Harbor was actually mined with 11,000 of these "destructors," as the U.S. Air Force called them, and less than a hundred conventional mines. Haiphong Harbor was shut down completely for months, and it took years to clear out all the American mines. The "destructor" mine design was so successful that it is still in use, using more modern electronics, as the Mk 62 mine.
During the 1991 Gulf War the Iraqis laid over a thousand mines off the Iraqi and Kuwaiti coast. The predominantly U.S. naval forces did not have sufficient mine sweeping resources to deal with this situation and had a helicopter carrier and cruiser hit and damaged while trying to clear the area. This effectively prevented any US amphibious operations, although the Marines were not going to be used for a landing anyway. It took over a month of mine clearing after the fighting ceased to eliminate all the mines. In the meantime, two U.S. warships were damaged by these mines. In 2003, the Iraqis again tried to use mines, but were hampered by prompt American, British, and Kuwaiti action.
In any future war naval mines will again surprise everyone with how effective they are. It is feared that terrorists might get their hands on some bottom mines, but so far, there do not appear to have been any attempts. Mines are basically robotic weapons and apparently the most effective way to deal with them is with robots.