Submarine Accidents and Incidents: Lessons from the Depths

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Submarines, the silent sentinels of the seas, are marvels of modern engineering, capable of operating undetected beneath the ocean’s surface. However, these complex machines and their missions are fraught with inherent risks. Over the years, several submarine accidents and incidents have underscored the perilous nature of underwater operations. By examining these events, we gain valuable insights into the vulnerabilities and advancements in submarine safety.

The Dangers of the Deep

Submarines operate in an environment where the pressure is immense, visibility is limited, and the margin for error is minimal. The risks range from mechanical failures and collisions to environmental hazards and human error.

When things go wrong underwater, the consequences can be catastrophic, often leaving little room for timely intervention. Once the submarine is found, there is no guarantee anyone aboard is still alive, even if the hull has not imploded. If one or more compartments have flooded, there may be survivors in other sections, but they will have limited air. And that is a key problem.

Notable Submarine Accidents and Incidents

1. USS Thresher (SSN-593)

One of the most tragic submarine accidents in history, the USS Thresher sank on April 10, 1963, during a deep-diving test off the coast of Massachusetts. All 129 crew members and civilians on board perished. The exact cause of the sinking remains uncertain, but it is believed that a piping failure led to flooding, causing the submarine to exceed its crush depth.

2. USS Scorpion (SSN-589)

On May 22, 1968, the USS Scorpion was lost with all 99 crew members in the North Atlantic. The submarine’s remains were found months later on the ocean floor. The cause of the sinking is still debated, with theories ranging from a catastrophic internal explosion to a torpedo malfunction.

3. K-129 (Soviet Submarine)

In March 1968, the Soviet submarine K-129 sank in the Pacific Ocean, resulting in the loss of all 98 crew members. The exact cause of the sinking remains a mystery, though it is speculated that a mechanical failure or an explosion of onboard weapons led to the disaster. The incident led to a covert U.S. operation known as Project Azorian, which aimed to recover parts of the sunken submarine.

4. Kursk (K-141)

The sinking of the Russian submarine Kursk on August 12, 2000, is one of the most well-known submarine disasters. An onboard torpedo explosion led to the deaths of all 118 sailors. The tragedy highlighted significant deficiencies in Russian naval rescue operations and prompted international calls for improved submarine safety and rescue protocols.

5. HMS Thetis (N25)

The British submarine HMS Thetis sank during sea trials on June 1, 1939, with the loss of 99 lives. A combination of human error and design flaws led to the flooding of the forward compartments. The tragedy resulted in significant changes to submarine safety procedures and the design of escape hatches.

Recent Incidents and Ongoing Challenges

1. KRI Nanggala (402)

In April 2021, the Indonesian submarine KRI Nanggala sank during a training exercise, resulting in the loss of all 53 crew members. The wreckage was found at a depth of more than 800 meters in the Bali Sea. This incident highlighted the challenges of submarine operations, including the difficulty in tracking and rescuing submarines in deep waters.

2. San Juan (S-42)

The Argentine submarine San Juan was lost in November 2017 with all 44 crew members. The submarine was found a year later at a depth of around 900 meters. The search for San Juan involved high-frequency sonar and underwater television cameras to meticulously examine the seabed.

Causes of Submarine Accidents

The underwater environment is a dangerous one. The current there can be the worst in the world, the weather there is the worst in the world and the seafloor there is less well-known than the surface of the Moon. Submarines face many perils of the deep. Even a small fire or gas leak inside a submerged submarine can have catastrophic consequences. Material and/or personnel may be damaged/ injured by fire. Sometimes there is an Explosion when Vapor explodes (not necessarily leading to fire).

Submarine hits another vessel or man-made infrastructure.A collision with another vessel or grounding may be much more serious for a submarine than for a surface ship. On 8 January 2005, the USS San Francisco struck an undersea mountain South of Guam, and one sailor died as a result of injuries received when the submarine came to a sudden stop. It may also be Grounded when the Submarine hits the bottom, shoreline or ice.

The next problem is the ocean floor is rarely flat it can be very hard to detect the vessel among seabed features. When Argentinian submarine San Juan in 2017  sank in 900 metres of water – the search for it, even though aided by triangulation of the seismic signature of its implosion at depth, took a whole year, with minute examination of the seabed using high-frequency sonar and underwater television cameras.

Human error has been identified as the major cause of accidents at sea. Unlike floods, the causes behind collisions involve human factors (operator error and/or an aggressive party) or a less-than-adequate capability to effectively detect (or be detected as the situation warrants) and quickly maneuver to avoid striking.

Causes could include a material or mechanical failure leading to catastrophic flooding of one or more compartments. It does not take much loss of buoyancy for a submarine to lose control of its depth. Nuclear submarines also have nuclear-related Incidents. Personnel may also be exposed to a toxic substance other than radioactive material. Early submarines were notoriously unsafe. However, when coupled with the drive to maintain a technological edge, these early losses resulted in improved design and operation.

Apart from the risks of an accident, there are the potential dangers with the increasing number of submarines working in the relatively confined and potentially dangerous seas of Asia. Some vessels might be engaged on intelligence and surveillance missions that take them into sensitive waters where they are at risk of being detected by another country’s anti- submarine forces.

1. Mechanical Failures

Mechanical failures, such as piping failures or propulsion system malfunctions, are common causes of submarine accidents. These failures can lead to catastrophic flooding or loss of control, making it difficult to surface or navigate.

2. Collisions and Groundings

Collisions with other vessels or grounding on underwater obstacles can have severe consequences for submarines. For example, the USS San Francisco struck an undersea mountain in 2005, resulting in one fatality and significant damage to the submarine.

3. Human Error

Human error, including operator mistakes and inadequate training, is a major cause of submarine accidents. Errors in navigation, operation, or maintenance can lead to fatal consequences in the challenging underwater environment.

4. Environmental Hazards

Submarines operate in a hostile environment where strong currents, severe weather, and unknown seafloor topography pose significant risks. These environmental factors can lead to accidents, such as the grounding or sinking of submarines.

Submarine Safety

Submarines must be maintained with the utmost diligence, adhering to a “zero tolerance” policy for even minor defects that could compromise their safety. The SUBSAFE program of the U.S. Navy exemplifies this approach, providing maximum reasonable assurance that submarine hulls remain watertight and can recover from unexpected flooding. This rigorous quality assurance program is essential for maintaining the safety of the nuclear submarine fleet.

Submarine operations are inherently high-risk and demand exceptional teamwork and trust among crew members. The successful and safe operation of submarines also relies heavily on accurate hydrographic and oceanographic data, which help navigate the often treacherous underwater environment. The complexity and danger of these missions require submariners to be among the most highly trained naval professionals, possessing advanced technical skills and proficiency in submarine escape procedures.

Effective command and control arrangements are crucial for submarine operations. These include detailed procedures for responding to incidents when submarines fail to report their location or surface on time, known as “Submiss/Subsunk” procedures. Pre-planned protocols are in place for instituting checks and initiating searches if a submarine fails to call in. These procedures swiftly transition from “SUBLOOK” (looking for a submarine) to “SUBMISS” (submarine is missing) and, when evidence of an accident surfaces, to the final stage, “SUBSUNK.”

Submarines are equipped with emergency indicator buoys that can be released to mark their position in the event of an accident, provided the crew is not incapacitated. In shallow water, these buoys remain tethered to the submarine, while in deep water, they become free-floating. When detected, search units must calculate back to the estimated release position, considering the impact of wind and currents on the buoy’s drift.

Communication with submarines, especially those engaged in sensitive missions, may not always be reliable. Therefore, comprehensive standard operating procedures must be in place to handle all eventualities, ensuring that submarines can operate safely and effectively in the demanding underwater environment.

1. Importance of Redundant Systems

Many submarine accidents have underscored the need for redundant safety systems. Failures in single points of operation, such as the loss of power or control, can be catastrophic. Modern submarines are designed with multiple backup systems to ensure continued operation even if primary systems fail.

2. Maintenance and Inspection

Submarines require rigorous maintenance and inspection protocols to ensure their safety. Programs like the U.S. Navy’s SUBSAFE provide maximum reasonable assurance that submarines will remain watertight and can recover from unanticipated flooding.

3. Advancements in Submarine Rescue

There are many challenges to tracking a submarine. First, they are inherently cover and unlikely to be tracked even when on a routine mission. Secondly is the limitations of sensors, even in a close-range exercise it can be very difficult to maintain sonar contact with a submarine. The inability to rescue trapped submariners in time has led to the development of advanced submarine rescue technologies. Submarine Rescue Vehicles (SRVs), Deep Submergence Rescue Vehicles (DSRVs), and Remotely Operated Vehicles (ROVs) are now integral parts of modern navies, capable of conducting rescue operations at significant depths.

4. Emergency Procedures

Navies have established comprehensive emergency procedures for dealing with overdue or missing submarines. These procedures, known as SUBLOOK, SUBMISS, and SUBSUNK, ensure a rapid and coordinated response to submarine emergencies.

5. Improved Training and Procedures

Accidents often result from a combination of mechanical failures and human error. Enhanced training programs and rigorous adherence to safety protocols have been implemented to minimize the risk of accidents.Submariners are among the most highly trained naval professionals. They undergo extensive technical training and are proficient in submarine escape procedures. Simulation-based training allows crews to practice emergency procedures in a controlled environment.

6. International Cooperation

Submarine incidents have led to increased international cooperation in rescue and safety operations. Organizations like the International Submarine Escape and Rescue Liaison Office (ISMERLO) facilitate multinational training exercises and the sharing of best practices. This collaboration ensures that navies worldwide are better prepared to respond to submarine emergencies.

Conclusion

Submarine accidents and incidents serve as stark reminders of the dangers associated with underwater operations. Each tragedy has spurred advancements in technology, safety protocols, and international cooperation, making submarines safer for those who serve on them. As we continue to explore and operate beneath the waves, the lessons learned from these somber events guide us toward a future where the risks are better managed and lives are more securely protected.

 

 

 

References and Resources also include:

https://aeasseincludes.assp.org/professionalsafety/pastissues/054/09/F2Tingle_0909.pdf

https://theconversation.com/submarines-are-designed-to-hide-so-what-happens-when-one-goes-missing-159634

https://www.rsis.edu.sg/rsis-publication/idss/895-perils-of-the-deep-the-danger/#.YMJspb6SlPa