USS Connecticut: Close encounter in the South China Sea

Media reported a U.S. Navy statement Thursday that USS Connecticut (SSN-22), a nuclear-powered attack submarine, had suffered an underwater collision on 2 October 2021 while operating in the South China Sea, and was headed to Guam for inspection.  No sailors were killed in the collision; 11 were injured, but the Navy hasn’t indicated the injuries are life-threatening.

The statement, quoted at the U.S. Naval Institute website, is as follows:

“The Seawolf-class fast-attack submarine USS Connecticut (SSN-22) struck an object while submerged on the afternoon of Oct. 2, while operating in international waters in the Indo-Pacific region. The safety of the crew remains the Navy’s top priority. There are no life-threatening injuries,” Capt. Bill Clinton told USNI News.

“The submarine remains in a safe and stable condition. USS Connecticut’s nuclear propulsion plant and spaces were not affected and remain fully operational. The extent of damage to the remainder of the submarine is being assessed. The U.S. Navy has not requested assistance. The incident will be investigated.”

Subsequent reports in the mainstream media have indicated Connecticut was in the South China Sea.

Connecticut is one of three Seawolf-class attack submarines and is homeported at Kitsap in the Bremerton, Washington naval complex.  USS Jimmy Carter (SSN-23), another unit of the class, is uniquely configured to support a wide array of special forces operations, but Connecticut’s ability to support special forces, while meaningful, is more limited and conventional.  As an attack submarine with antisubmarine, antisurface, land strike (i.e, Tomahawk), and intelligence collection capabilities, Connecticut is as well-equipped as any U.S. SSN.

The sub deployed for an operational patrol on 27 May 2021.

A report from the Kitsap Sun on 9 October said Connecticut pulled into Guam on Friday.  Two sailors “who received ‘moderate’ injuries were treated at a local military treatment facility but not admitted,” the Sun quoted Cynthia Fields, a spokeswoman for the U.S. Pacific Fleet Submarine Force, as saying.

No details about the collision have been reported.  The Navy refers to the object struck as unidentified, but reportedly has said it was not the vessel of a foreign navy.  The Kitsap Sun:

A Navy official on background said it was not a vessel of the Navy, either one of the U.S. fleet or that of a foreign power. 

A few comments.

We can assume at this point that the “object” collided with was not a commercial surface ship; e.g., a cargo ship or fishing vessel.  There would have been open-source reporting on such an event even before the Navy announcement on Thursday, 7 October.

The 7 October announcement was clearly timed to herald Connecticut’s arrival in Guam the next day, which could not be hidden.  We’ll see if images emerge from the sub’s pier in Guam.  Damage to the sub may or may not be visible from above the waterline.

The sub’s most sensitive systems, including major weapon systems, apparently weren’t damaged.  The reporting has said Connecticut was able to surface after the collision (always the first concern with submarine damage; Submerge – Surface = 0 is the only acceptable outcome).  It hasn’t been entirely clear that Connecticut transited all the way to Guam on the surface, although I’ve seen commentators suggesting that was the case.  It may have been at periscope depth rather than fully surfaced.  We know too little about the collision itself to speculate intelligently much beyond that.

As for discerning where in the South China Sea Connecticut might have been, the time-distance factor doesn’t help us a whole lot.  If the sub was operating in the central-to-northern part of the SCS, and went to Guam through the Luzon Strait north of the Philippines’ Luzon Island, it would have required approximately a 12-knot speed of advance (SOA) to make the trip between 2 and 8 October.

Potential USS Connecticut operating areas in the South China Sea centered on the Spratly and Paracel Islands, in relation to speed required to transit to Guam. Google map; author annotation

If SSN-22 was in the central-to-southern part of the SCS, and went through either the Luzon Strait or the Balabac Strait, Sulu Sea, and Celebes Sea to reach the Pacific, the longer trip would have required more like a 16-knot SOA.

In either case, the transit in the time indicated is feasible from as far as the western side of the SCS, as long as Connecticut didn’t have a major propulsion casualty. 

The presence of an “unidentified object” underwater is an interesting clue suggesting that Connecticut was not in the heavily trafficked transit lanes of the SCS at the time of collision.   The sub could of course have been much deeper than the keel of any surface ship, but colliding with something that significantly rattled the Connecticut’s hull, with the force to injure sailors inside of it, would indicate an “object” capable of exerting counterforce when hit.  Something of substantial mass, and either stationary or under power, seems to be the candidate.

If it wasn’t a submarine or submersible vessel of some kind, it’s likely to be an important question what it was.  That would be because of the potential that someone placed it there.

It’s conceivable that it was a seamount, but the Navy hasn’t spoken as if it was.  The news stories allude to USS San Francisco’s (SSN-711) collision with a seamount in 2005, but that reference hasn’t been suggested as explaining what Connecticut hit.  (If Connecticut hit a seamount, the Navy would almost certainly know that already.  Even if it’s a suddenly erupting or growing seamount, conferring with the U.S. Geological Survey and NOAA should yield answers pretty quickly.  Whether the public would be told just yet is another story.)

There’s no way to pin it down, but given the priorities of the U.S. military, one possibility is of course that Connecticut was operating near one of the reefs China has been artificially building out to accommodate military installations.  If new undersea hazards had not been catalogued in parts of the South China Sea, those would be especially likely locations.

Map graphic: CSIS Asia Maritime Transparency Initiative. See:

But, again, what we can say at this point is that it’s feasible for Connecticut to have been in one of those locations for a collision, and to have transited from the collision site to Guam in six days, as long as no propulsion casualty limited her speed to below 12 knots.

As for whether Connecticut may have been operating near a Chinese submarine:  sure.  The Navy says our sub didn’t hit another nation’s naval vessel, but, of course, our sub could have hit something else while tracking a Chinese sub.  The question again would be where the requisite type of “object” would be, and what it’s there for.

There’s a lot of depth available in the SCS.  A submarine doesn’t have to be relatively shallow when it’s operating there.

But encountering an object no one knows about down deep would be the factor requiring an explanation here.  It will be interesting to see if we get one.  (I’m discounting an alien vessel like the one in James Cameron’s The Abyss, from 1989, but feel free to ponder that as well.)

Beyond these considerations, we can note, as reported by the mainstream media, that China professes to know nothing, and is demanding answers from the United States on the pretext of being concerned about environmental damage and maritime safety.

We can also note that at the time of the collision, the U.S., Japan, and UK were conducting a “four carrier” exercise with a slew of escort ships in the Philippine Sea (Japan’s JS Ise, capable of supporting both helicopters and the F-35B strike-fighter, being the fourth carrier).  Obviously China had a great interest in that.

China would not have responded to that, per se, by driving subs around the South China Sea or placing undersea objects there.  But China doesn’t need anything other than her own preexisting strategic priorities as the motive for submarine deployments and altering the maritime environment.

A final observation can’t fail to be of interest.  The collision reportedly occurred on 2 October.  China had been sending waves of military aircraft through Taiwan’s Air Defense Identification Zone (ADIZ) in the days just before that, and on 4 October set a new record for the number of PLAAF warplanes entering the Taiwan ADIZ.

Taiwan Ministry of Defense graphic

I always stress that entry into an ADIZ isn’t entry into a nation’s internationally recognized air space.  The mapped incursions by China indicate that the PLAAF is remaining outside the 12 nautical miles that would be Taiwan’s air space boundary, if Beijing recognized it.  This can’t be done everywhere in the ADIZ, but it can be done on the southwest corner of it.  That’s where the Chinese planes have been operating.

The timing, at any rate, is eye-catching.  The probability that the Connecticut collision had something to do with China is non-negligible.

5 thoughts on “USS Connecticut: Close encounter in the South China Sea”

  1. Perhaps that unknown object was ‘Xi Fireworks’ launched from the seabed, to make Oct. 10 doubly exciting?
    “10 10 is Double Tenth Day, the start of the Wuchang Uprising of 10 October 1911. The revolt marked the end of the Ching (Qing) Dynasty that had been established in 1644 by the Manchus. The revolt led to the founding of the Republic of China on 1 January 1912. … Following the Chinese Civil War, the Government of the Republic of China lost control of mainland China to the Communists and relocated to Taiwan in 1949.”

    Wish I could format here…

  2. I’ve been poking through this event.. it does sound “hinky” and Connecticut seems to have been operating in an area where the “keeping a quiet eye on things” sort of operation is the preferred course of action. Okay, haven’t been through any unclassified summaries of the configuration and capabilities of the SSN-21/22 (Seawolf and Connecticut) subs, but my memory isn’t horrid, yet, and the configuration for the time was on the “newish side”. the bow area contains the main sonar (active and passive array) and no weapons tubes. There is a towed array setup somewhere amidships with enough line to trail off to one side or the other of the boat. Sound gear is the first weapon of every sub. Since the report contains the “fact” that none of the weapons systems were damaged, that means the lower portion of the hull amidships (where the eight launch tubes are housed – 4 port and 4 starboard – at least by known publications like Jane’s) mean that a lower hull strike is not probable… It does look for all the world like some sort of “collision” while operating at periscope depth.. I’d have to guess as to what that is measured from the surface to the keel of the boat.. couldn’t be more than 85 to 100 feet… and yes I know that the new fiber optic and advanced systems allow the sub to operate at deeper periscope depths, but if it was snooping around, it was probably deploying more than visual surface sensors.

    It all speaks of hard contact from something sub surface that purposefully maneuvered to strike the sub.. 1) If the Chinese did something, they certainly wouldn’t admit it, under any circumstances. 2) I get concerned about blind spots in the sensor arrays if it was an admidships strike… regardless of the cause. 3) If nothing was severely damaged I can’t imagine (as you note) that they’d transit to Guam on the surface.. (modern subs aren’t World War II era Gato and Balao class subs that were designed to operate on the surface. (by the way, the silent service owned the South China Sea by the end of WWII and nothing hostile was safe. It’s a pretty well mapped area, and some secret seamount, though possible is not probable.)

    I do note your map and track of the Chinese air space “challenges” being all in the Southwest corner of their warning zone. I find that abundantly interesting and I am sure that the Naval and Air Intelligence folks have been attracted to figuring out why that zone seems to be so “interesting” to the PLAN and PLAAF… You’d think they’d be playing cat and mouse games at various locations if they were really planning on an invasion. Maybe our snooping in the area attracted some over the top attempt to stop it.. an undersea drone, perhaps? Something that would slam into the sub hard enough (burst of speed…from slow and creeping to go full speed in a blind spot) to send it away… and then have the drone break up and sink into the depths… leaving no real evidence..

    Dunno.. but it’s a worrisome game of chicken if it is.


    1. Please forgive the typos.. need more coffee… and it’d really be nice if there was a comment editor on the WordPress site..

    2. Not to worry about the typos, OAB.

      Regarding where the Chinese are flying in the Taiwan ADIZ, that’s what my point about the 12NM limit explains.

      A lot of observers have mused curiously about the Chinese flight paths, but they’re not a mystery at all. The Chinese are flying through the only part of the ADIZ that’s IN the ADIZ, but OUTSIDE the 12NM limit draw from Taiwan’s coastline. That 12NM boundary applies to both territorial seas and airspace. (You can see in the Taiwan Strait itself that the center line between the mainland and Taiwan splits right about 12NM-12NM. That’s why China never flies there to make a point of being in Taiwan’s ADIZ: because crossing from Chinese airspace over the center line can’t be done without approaching Taiwan closer than 12NM.)

      China doesn’t formally recognize Taiwan as having sovereign seas or airspace, but nevertheless respects the 12NM line. That’s evident in every entry the PLAAF makes into the Taiwan ADIZ.

      The game of chicken will ratchet up to teen-angst-movie level if China commences little micro-incursions on the 12NM line. I’m definitely hoping not to see that happen. So far deterrence has been preventing it.

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