The US Navy SEALs now have a special place on their submarines to conduct undersea operations without making a sound.
In 2017, Daniel Brown from Business Insider wrote a report on the USS John Warner, a Virginia-class attack submarine, in which he mentioned a ‘Lockout trunk’.
A Lockout Trunk is a specially developed compartment near the top of a submarine, which fills up with water and then empties, allowing special mission divers such as Navy SEALs to put on scuba gear, wait for the trunk to fully submerge and then exit the submarine quietly.
The National Interest reported that such a compartment was added during the construction of the Virginia-class attack submarine’s Block III variant.
Another Virginia-class submarine, USS New Mexico (SSN 779), recently conducted a training in the Mediterranean sea in which US Navy SEALs “rehearsed command and control architecture, staged equipment, and conducted diving operations utilizing the submarine’s large lock-in/lock-out chamber,” according to a US Navy 6th Fleet press release.
“This training demonstrated how the submarine force can adapt mission sets for theater commanders, providing a variety of options to address multi-domain challenges,” said Rear Adm. Anthony Carullo, Director of Maritime Operations, US Sixth Fleet and Commander of Submarine Group 8.
Among other advantages of Lockout Trunks, the primary benefit is the ability to carry out underwater warfare missions without enemy detection.
Underwater special operations include intelligence-gathering and surveillance tasks. Military reconnaissance refers to scouting or exploration of an area to obtain information about enemy forces, terrain, and other activities.
Diving sabotage is another underwater operation in which unauthorized divers or “frogmen” are sent to hostile territory to gather information or cause damage to the enemy naval assets.
Popular Mechanics reported on such “ghost” divers that many countries including the US and China are scared of.
Other underwater missions include targeted attacks, secret rescue missions, or hostage recovery operations which can be performed with a much smaller, much less detectable acoustic signature, as reported by National Interest.
This helps divers or in this case, Special Operation Forces, avoid detection by highly sensitive sonars. Although they would emit an acoustic signature, it would be non-detectable similar to an acoustic signature of a large fish, dolphin, or shark.
The Lockout Trunks are also important for escape missions during a disaster or a sunken submarine.
In case of an enemy attack, the Navy SEALs can escape using the trunk and then swim to retrieve what is known as a special-forces operations box, which would be filled with weapons and needed gear, from the tower, as per Brown’s report.
Throughout the history of naval warfare, submarine innovation has provided solutions to rescue the crew of a sunken submarine.
One of the earliest solutions was called “Escape Lungs”. The lungs were devices that recycled an escapee’s breath, using a chemical reaction to remove carbon dioxide and adding more gas as needed. The lungs were routinely stashed onboard submarines like the UK Royal Navy HMS Thetis, which sank during sea trials in 1939.
Modern-day submariners are equipped with full-body waterproof suits called Submarine Escape Immersion Equipment or the SEIE suits that allow the crew to escape from depths of 600 feet. Once in the open sea, the suits essentially become a life raft that protects the crew from drowning and hypothermia.
UK-based company Suvitech has specialized in designing, manufacturing, and supplying the most advanced safety solutions since the 1930s.
The newest suit called MK11 is a full body garment designed for pressurized tower escape with a fully integrated single-seat liferaft.
The US Navy is reportedly working on a submarine Deep Escape System which comprises a flood valve, auto-vent valve, single-man escape suit, and an escape suit hood inflation system among other components.
The need for an effective and efficient escape trunk has risen given the threat posed by unmanned underwater combat drones.
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