Saving Submariners: Submarine Rescue and Escape
- Rescue is safer — escape methods expose survivors to hazardous conditions, like cold water and immense pressure, and are prone to mistakes.
- Rescue vehicles can operate much deeper (2,000 feet) than escape gear, which is limited to shallow water (600 feet or less).
- Rescue operations provide onsite resources, like a decompression chamber, to treat survivors.
The best way to safeguard a submarine and its crew is to avoid or quickly halt an accident. Submariners do this through extensive training, learning to do their own jobs and everyone else’s on the sub. They also run drills to practice plugging leaks (left) and extinguishing fires. Time is of the essence — a crew must control a casualty (emergency) within five minutes to save the sub and their lives.
Possibility of Rescue
Submarines can withstand pressure to a certain depth. If a submarine sinks below this point, called crush depth, its hull will collapse under the pressure.
Although submarines spend most of their time operating in the deep ocean, they are more likely to have an accident in shallower water (due to sea trials, diving and surfacing, transiting with open hatches near port, etc.), where they can survive.
Rescue: The Go-To Approach
Until 1939, the world’s navies believed rescue had little chance of saving trapped submariners. Then the U.S. Navy raised 33 survivors from the sunken USS Squalus in May 1939 using a rescue chamber, forever changing the rescue paradigm.
Following the successful Squalus operation, the Navy embraced rescue as its preferred approach. Over time, it has developed new rescue technology that continually improves its rescue abilities.
“Is There Any Hope?”
On December 17, 1927, Coast Guard destroyer Paulding struck surfacing submarine USS S-4. Salvage boats hurried to raise the submarine in hopes of saving the crew. Divers located six survivors by tapping on S-4’s hull, but weather thwarted all efforts to move the sub. Sixty hours into the operation, the trapped men tapped “Is there any hope?” Heartrendingly, the divers answered “no.” All 40 crew died in the accident.
Submarine Rescue Chamber
In service 1930s–Present
Commanders Charles Momsen and Allan McCann co-designed the submarine rescue chamber (SRC) after S-4’s loss. In less than 850 feet of water, a salvage ship can lower a rescue chamber to a disabled submarine to raise survivors to the surface. The Navy has used a chamber once for an actual rescue, to save 33 submariners from USS Squalus in 1939. Today the SRC remains part of the Navy’s rescue arsenal because its simple design makes it effective and reliable.
Rescue Gets Cutting-Edge: The DSRVs
In service 1970–2008
With the 1963 sinking of USS Thresher (SSN 593), the Navy realized submarines were operating deeper than rescue equipment could reach. The deep-ocean program it formed in response designed two sophisticated rescue submersibles called DSRVs (deep submergence rescue vehicles). When needed, a DSRV could be rapidly deployed by sea, air, or land to rescue submariners anywhere in the world. DSRVs Mystic and Avalon were launched in the early 1970s, given full operational status in 1977, and served as the Navy’s submarine rescue system through 2008.
Inside a DSRV’s outer fiberglass hull, three high-strength steel spheres formed the pressure hull. Two pilots operated the DSRV from the forward sphere, while the mid and aft spheres could hold one rescuer and 12 submariners.
At a rescue site, a specially-configured submarine or a submarine rescue ship carried the DSRV close to the sub. The DSRV could then descend, attach to the submarine’s escape hatch, and transfer rescued submariners to the support vessel in groups of 24.
Who rescues the submariners on a disabled sub?
Initially, any ship that encountered the submarine (often the ship that collided with it). With its establishment in 1927, the Navy Experimental Diving Unit became the first command responsible for submarine rescue.
The Navy created a dedicated command, the Submarine Rescue Unit, after its new rescue vehicles (DSRVs) entered service in the 1970s. Rebranded over time, the unit became the Deep Submergence Unit in 1989 and received its current name, the Undersea Rescue Command, in 2012.
Rescue Today: The SRDRS
In service 2008–Present
In 2008, the Navy adopted an updated rescue system, the Submarine Rescue Diving and Recompression System (SRDRS). The SRDRS carries out an operation in three parts:
- Reconnaissance — examining the downed sub’s conditions with an atmospheric diving suit
- Rescue — raising survivors using a rescue module named Falcon
- Decompression — transferring the crew from Falcon to a decompression chamber to avoid uncontrolled pressure changes
As an easily transportable “fly-away” system, the SRDRS is easier and faster to deploy than its predecessors, the DSRVs.
The Navy’s modern rescue systems, including the DSRVs and the current SRDRS, are purposely compatible with the submarines and rescue systems of navies throughout the world. The U.S. Navy regularly takes part in rescue exercises with other nations and has official submarine rescue partnerships and agreements in place with more than 40 countries.