Nearly every mine warfare article or presentation starts off with the same sentence: “Naval mines have sunk or damaged more ships since the end of World War II than all other weapons combined.” This rhetoric, while true, has done nothing to sustain a U.S. strategic mining capability. A new breed of strategic underwater weapons unmanned has the potential to reshape not just mining but also antisubmarine and surface warfare.
The Strategic Mining Option
Naval mines are used for coastal and harbor defense, area denial, antisubmarine, and antisurface warfare, as well as blockade operations. Their use as a strategic shaper of the maritime battle space goes back to the U.S. Civil War and were used in World Wars I and II, the Korean War, the Vietnam War, and the Gulf War in part because “sea mines are key to regional navies’ antiaccess/area-denial (A2/AD) and sea-control strategies and operations.”[1] Mines are cheap and easy to build compared with other weapons and can have the same impact as multiple ships and aircraft. They allow nations without economic spending power to strategically influence maritime confrontations, as the mere threat of an enemy minefield can significantly influence naval and amphibious operations and timelines.
There are various classifications of mines—moored, bottom, and drifting mines—and they can be either contact or influence activated. Naval mine fields are classified with respect to recognized geographic boundaries.
- protective minefield: A minefield laid in friendly territorial waters to protect ports, harbors, anchorages, coasts, or coastal routes.
- defensive minefield: A minefield laid in international waters or international straits with the declared intention of controlling shipping in defense of sea communications.
- offensive minefield: A minefield laid in enemy territorial waters or waters under enemy control.[2]
U.S. Mining and Legal Constraints
The current U.S. mine inventory is limited to the Quickstrike mine series (MK-62, 63, and 65) and the MK-67 submarine-launched mobile mine. Quickstrike mines are general-purpose bombs that have been converted to mines and are used primarily in shallow water against surface contacts. Quickstrike mines are deployed from strategic or tactical aircraft to form offensive, defensive, or protective minefields. Alternatively, the MK-67 is launched from a submarine torpedo tube, and the stealth nature of the submarine delivery makes these mines ideal for offensive minefields. The U.S. Navy has no surface mine-laying capability.
The earliest legal mine-laying guidelines come from the 1907 Hague Convention VIII. It placed restrictions on drifting and moored mines; set guidelines on laying automatic contact mines off ports with the intent of intercepting commercial shipping; and set requirements to remove mines after a conflict. Additionally, the 1982 U.N. Convention on the Law of the Sea (UNCLOS) has become customary international law, though the United States has not signed it. The primary focus of the UNLOS is on reserving the use of the high seas for peaceful purposes and freedom of navigation rights. The treaty is not meant to constrain military operations consistent with international law. Additionally, the UNCLOS established an internationally recognized 12-nautical mile territorial sea limit.
These two treaties have led to the guidelines and policy in the Department of Defense Law of War Manual, which states, “Mines are lawful weapons; however, specific rules apply to their use.”[3]
- Peacetime Mining
- Naval mines may not be placed in the internal waters, territorial sea, or archipelagic waters of another state in peacetime without that state’s consent.
- If a state places armed mines in their own territorial sea or archipelagic waters, they must notify the international community of the existence and location of the minefield.
- Armed mines may not be placed in international straits or archipelagic sea lanes during peacetime.
- Controlled mines emplaced in a state’s own archipelagic waters or territorial seas are not subject to notification or removal requirements.
- Mining in International Waters
- Controlled mines may be placed in international waters if they do not unreasonably interfere with other lawful uses of the area.
- Since controlled mines do not constitute a hazard to navigation, international notice of their placement is not required.
- Armed mines may not be placed in international waters prior to the outbreak of armed conflict.
On the Outs
Mining has fallen out of favor with the U.S. Navy for a number of reasons. The lack of controlled actuation creates an increased risk that a mine detonates on its own or on neutral shipping.
Additionally, the mining mission is a low priority for both the mine delivery assets and their mine load-out capacity. U.S. mines are placed either by submarine or aircraft (Air Force bombers or Navy P-3 and F/A-18 aircraft), and mining is a secondary or tertiary mission for these aircraft and operational control of the assets falls outside of the mine warfare commander. Mining missions must be sourced with the Combined Force Maritime Component Commander or Joint Force Maritime Component Commander staffs, who in turn must negotiate these missions with the air component commander, strike commander, or antisubmarine warfare commander. Furthermore, aircraft sorties for offensive mining are risky without air superiority and are often not worth the potential loss of the aircraft and crew.
U.S. protective mining capability has severely degraded over time, and its offensive mining capability suffers. The paradox of offensive mining is that to be effective, offensive minefields must be placed before a conflict starts, which is generally considered an act of war and restricted by the rules of engagement. Once conflict escalates, it is often too late to conduct offense mining missions.
A Technological Solution
The moored mine and torpedo have a shared genesis. During the battle of Mobile Bay in August 1864, Admiral David Farragut is famed to have said, “Damn the torpedoes. Full speed ahead.” The torpedoes he referred to were moored naval mines.
Nearly 150 years later, the technology exists to build an advanced underwater weapon that combines the capability of both mines and torpedoes. This new asymmetric underwater weapon could be capable of mining an enemy port or sinking enemy ships at the pier. Either option prevents enemy ships from laying mines or conducting other naval missions. Most important, a weapon of this type would solve the legal and operational concerns with respect to maritime mining; it would be accomplished at a fraction of the cost of a single ship and would eliminate the risk to ships, aircraft, and crewmembers.
This underwater smart weapon design would utilize an underwater unmanned vehicle (UUV) as the payload delivery vehicle and perform the missions of both a moored/bottom mine and a torpedo—the “moor-pedo.”
Figure 1: Moor-pedo Design
Figure 1 follows traditional UUV design with several modifications to take advantage of the latest technological advances in propulsion and energy storage. The communications subsystem would utilize an iridium antenna capable of extending to the surface while the moor-pedo is lurking in a neutral state. A small temporary anchor could be housed internally for one-time mooring. The mine influence subsystem would utilize a mine target-detection device, which would actuate an influence trigger in the shaped-charge warhead located in the nose. The warhead could be initiated via magnetic, acoustic, or pressure influence depending on the desired target, or upon impact with the hull of a moored ship. It would use GPS and/or inertial navigation systems; there would be no need to retrieve sensor data, but a side-scan sonar subsystem could be added to assist with navigation.
Concept of Operation
The moor-pedo would function as either an influence mine against ships coming in or out of a port or as a slow-moving torpedo/contact mine against moored ships. Multiple moor-pedoes could be clandestinely deployed prior to hostilities starting while enemy ships are still in port and political negotiations are in progress. These weapons could also be used after hostilities occur to prevent ships and submarines from entering ports for re-supply. The moor-pedoes would be launched in international waters by a surface ship, small boat, or helicopter and transit to a loiter area outside of the territorial limit for a designated enemy port, remaining in international waters. Once in the loiter area, the moor-pedoes would deploy their temporary anchor to maintain their position and deploy their floating antenna.
Propulsion and electronic subsystems would be powered down to conserve batteries; however, the communications system would remain alert enough to receive an activation signal. In this dormant state, the moor-pedoes would not be considered armed mines and would not pose a threat to navigation for surface vessels. According to the legal guidelines, international notification of their placement location is not required and no violation of rules of engagement will have occurred. The moor-pedo could remain in this loiter location for several weeks while intermittently checking for an activation signal via the iridium antenna. If the situation is settled diplomatically, a command would be sent to the moor-pedos to transit to a designated recovery location or to detonate in place. If the situation escalates to conflict, an activation signal would be sent to the moor-pedoes, which would then activate their navigation system and receive an updated GPS position and their designated track/target plans via the antenna. This downlink of position, track, and target data could be sent from a satellite or an unmanned air vehicle such as an MQ-8 Fire Scout or RQ-4 Triton. The moor-pedos would then release the temporary anchor and restore the propulsion systems. The vehicles would then dive to attack profile and commence the mission track. Alternatively, the Navy could designate a single UUV as the communications vehicle and send an acoustic signal to the other moor-pedoes to activate.
Figure 2: Simulated Moor-pedo Loiter Field
The moor-pedoes would arrive at the enemy port in a matter of hours and could follow various attack profiles.
Bottom Mine Option: A moor-pedo designated as influence mines would navigate to exact positions at the entrance of the harbor, alter buoyancy to sink to the bottom, and activate its mine target-detection device to become bottom-influence mines. It would prevent enemy ships from returning to port if already underway or impede ships sorting to sea from an unknown berth.
Torpedo Option: The vehicle would use high-resolution satellite imagery to determine the exact location of enemy ships moored at piers or anchorages. The fidelity of the target coordinates would be accurate enough not only to drive the moor-pedo into an enemy ship, but to have it make contact at a specific location, such as the stern where the propellers are located.
Moored Mine Option: The moor-pedo could deploy directly to the mining coordinates without stopping in a loiter box, using the internal anchor to function as a moored-influence mine in the near-surface region.
Summary
The moor-pedo could provide the United States with a cost-effective strategic solution to current mining problems that doesn’t require placing an expensive delivery platform or personnel at risk. The design provides flexibility to function as a bottom-influence mine, moored-influence mine, or slow-moving torpedo. Their precise positioning capability would result in far fewer assets needed to achieve a desired minefield measure of effectiveness.
From an operational concept, the moor-pedo would adhere to all international guidelines on mining. Additionally, these weapons would be capable of being emplaced or detonated within a matter of hours as opposed to days to weeks with traditional mines—all without risk to a single ship, submarine, or aircraft. Most important, the moor-pedo is within the capability of current UUV. The Navy could develop larger UUV to provide a deep-water moored mine capability to act as a barrier minefield or a design that could be launched from the Navy’s large displacement unmanned underwater vehicle, which would provide an increased operational range from the host surface platform or port location.
Figure 3: Example of a Moor-pedo Attack Profile
[1] Scott Truver, “Taking Mines Seriously: Mine Warfare in China’s Near Seas,” Naval War College Review: Vol. 65 : No. 2 , Article 5 (2012), https://digital-commons.usnwc.edu/nwc-review/vol65/iss2/5.
[2] Joint Chiefs of Staff, Naval Tactics, Techniques, and Procedures (NTTP) 3-15_2, Naval Mine Countermeasures, 2011.
[3] Office of General Counsel, U.S. Department of Defense, Law of War Manual (Department of Defense, 2016), https://dod.defense.gov/Portals/1/Documents/pubs/DoD%20Law%20of%20War%20Manual%20-%20June%202015%20Updated%20Dec%202016.pdf?ver=2016-12-13-172036-190.
