- The U.S. Coast Guard and foreign navies are mobilizing to rescue a private tourism sub, Titan.
- The sub and its passengers were equipped to travel up to 12,500 feet underwater, deep enough to visit the wreck of the Titanic.
- The submersible may be so deep that not even military rescue submarines can reach it.
The missing civilian submarine Titan, built to dive to one of the most inhospitable places on Earth, could be out of reach for even military rescue teams.
The submarine was reportedly visiting the wreck of the famed sunken cruise ship, Titanic, when it was reported missing on June 18 with five people on board. Coast Guard and military assets are currently conducting a thorough sweep of the submersible’s last known location—a remote part of the Atlantic Ocean about 435 miles south of St. John’s, Newfoundland, off the coast of Canada—but those efforts may be inadequate if the sub is stuck at the Titanic wreck location, nearly 13,000 feet deep.
Built to Dive Deep
Titan, according to operator OceanGate, is a 22-foot-long commercial submarine. It has a crew of one, including the pilot, and four passengers. The sub is made of titanium and carbon fiber, and as a result has a maximum diving depth of 13,123 feet. Unlike some submersibles, the Titan has its own propulsion system, consisting of four Innerspace 1002 electric thrusters, giving it a top speed of 3 knots. It is also equipped with an inertial navigation system to determine its position—while submerged, the sub would be unable to poll the worldwide constellation of GPS satellites to determine its position.
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The submarine does have some systems in place to deal with emergencies. According to CBS News, in the event of an emergency, it has seven different ways to rise to the surface involving “multiple redundant ballast and air-bladder systems.” The reporter states that as of summer 2022, Titan lacked an emergency beacon, and that after a prior episode in which the sub got lost for five hours, there was some discussion of adding one. Whether or not that actually happened is unknown at this point, but the nature of emergency beacons suggests that if it did, the submarine’s passengers and crew would have been rescued by now.
All of this means that the submarine could be floating on the surface of the Atlantic Ocean, safe and awaiting rescue, stuck under two and a half miles of water, or virtually any place in between. Based on information released by OceanGate and the U.S. Coast Guard, there is really no way of knowing at this point.
Search and Rescue
A spokesperson for U.S. Coast Guard’s First District, responsible for the Atlantic Ocean region, stated that the service was coordinating search-and-rescue efforts with the Canadian Coast Guard and the U.S. Air National Guard. Two Coast Guard C-130 Hercules, a New York Air National Guard HC-130J Combat King rescue aircraft, and a CP-140 Aurora, Canada’s version of the P-3 Orion maritime patrol aircraft, have all participated in the search so far.
Currently, the open-source airplane tracker ADS-B Exchange shows no military or Coast Guard aircraft over the search area. However, it’s common for military aircraft to turn off their ADS-B transponders in midair, so there still might be aircraft in the vicinity.
Journalist Chris Cavas reports the Coast Guard buoy tender Sycamore is headed to the area to assist in the search. The Canadian Coast Guard ship Kopit Hopson is steaming to the vicinity of the missing sub, but at last report, was still a day’s sailing away. Another Canadian Coast Guard ship, the offshore fishery science vessel John Cabot, is also headed to the area. USNI News reports that a Canadian warship, the HMCS Harry De Wolfe, was also steaming to the area.
Unfortunately, none of the ships en route are equipped for a deep-water rescue.
A Shortage of Military Options
If the submersible has managed to surface, chances are good searchers will locate it and rescue the crew. U.S. Coast Guard C-130s are equipped with a 360-degree, belly mounted surface search radar designed to pick up small objects floating on the surface of the water. If the U.S. Navy gets involved, the P-8 Poseidon anti-submarine warfare aircraft features a nose-mounted AN/APY-10 surface search radar designed to pick up objects as small as submarine snorkels. The AN/APY-10 has a search range of up to 250 nautical miles, giving it the ability to quickly scan large patches of ocean.
If the Titan is still underwater, the situation becomes grim. The U.S. Navy maintains a submarine rescue capability able to deploy on short notice. The Submarine Rescue Chamber, or SRC, is a small diving bell operated by the Undersea Rescue Command and stationed at Naval Station North Island, California. The SRC is air transportable and can be flown via C-5M Super Galaxy or C-17 Globemaster III transport aircraft anywhere in the world. In November 2017, the U.S. government sent the SRC to Argentina to help search for the missing submarine ARA San Juan.
Unfortunately, the SRC has a maximum operating depth of just 850 feet, far short of the 12,000 feet the Titan could be located at if the sub ran into trouble at the wreck site. Another U.S. Navy rescue asset, the Pressurized Rescue Module, can dock with a stricken submarine at up to 2,000 feet. NATO’s Submarine Rescue System, jointly operated by the U.K., France, and Norway, can also dive to 2,000 feet. Even if any of these rescue assets could reach the sub, it’s unclear if the civilian-designed and built Titan can “mate” with a military rescue submarine, creating a waterproof, pressurized seal that would allow people to move from one vehicle to the other.
✅ Why can’t military rescue assets dive as deep as the Titanic wreck? The hulls of naval submarines are generally rated to a maximum diving depth of 3,000 feet or less. If a submarine goes deeper than that, the pressure will eventually collapse the hull from the outside, killing the crew. If a U.S. Navy Virginia-class submarine were to sink to a depth of 12,000 feet, there would be nobody left alive to rescue.
The search for the Titan grows more desperate by the hour, and as of Wednesday morning, the sub was believed to have less than 20 hours of oxygen left. The military’s rescue of mountain climbers, sailors attempting solo voyages, and other adventurers have given it a reputation of the ultimate rescue service. Unfortunately, in this case, if the Titan is still at the Titanic wreck site, there is little the military can do.
Kyle Mizokami is a writer on defense and security issues and has been at Popular Mechanics since 2015. If it involves explosions or projectiles, he's generally in favor of it. Kyle’s articles have appeared at The Daily Beast, U.S. Naval Institute News, The Diplomat, Foreign Policy, Combat Aircraft Monthly, VICE News, and others. He lives in San Francisco.