USS Montpelier Collision

The Navy got an unwanted present on its 237th birthday when USS Montpelier (SSN 765) and USS San Jacinto (CG 56) collided off the East Coast today:
NORFOLK, Va. (NNS) -- There were no injuries as a U.S. Navy submarine and an Aegis cruiser collided off the coast of the Eastern United States earlier this afternoon.
The collision between USS Montpelier (SSN 765) and USS San Jacinto (CG 56) occurred at approximately 3:30 p.m. Eastern Daylight time.
No personnel aboard either vessel were injured.
Overall damage to both ships is being evaluated. The propulsion plant of the submarine was unaffected by this collision. Both ships are currently operating under their own power.
The incident is currently under investigation.
Both the submarine and the ship were conducting routine training at the time of the accident.
Montpelier returned from deployment in February, while San Jacinto is assigned to Carrier Strike Group TEN with USS Harry S Truman (CVN 75), which is in a deployment workup cycle. Here's some more information from the ABC News website:
The Navy official says that at approximately 3:30 p.m. the bridge watch aboard the San Jacinto saw the submarine Montpelier rise to periscope depth about 100 to 200 yards ahead of them. The bridge ordered an “all back,” but still collided with the sub.
According to the official, the initial assessment of damage is that there was a complete depressurization of the sonar dome aboard the San Jacinto. Located below the water line of surface warships, sonar domes provide the bulbous shape to the bows of warships.
After the collision the official said the submarine surfaced and communications were established between all the ships on the scene.
Will update as more information becomes available. Staying at PD...

Update 2130 14 Oct: The Navy reports that both ships are pierside and being evaluated. In this picture of Montpelier, it appears that the upper section of her rudder is missing.

I've always thought that there was no more dangerous peacetime evolution (other than some ORSE prep drill sets) than fleet ASW exercises away from an instrumented range. During Topeka's 1992 deployment, we did an opposed UNREP against the Ranger Battle Group. After one simulated attack, we moved ahead of the group to get in position for a follow-up green-flaring. As we were coming to PD with the CO ("He Who Must Not Be Named") on the 'scope, the Weps watching the ASVDU, and me on Pri-MATE, the dots were stacking in such a way that it looked like a contact was coming closer and closer, and we started getting near-field effect on the sonar displays. The WEPS recommended we abort the PD trip, and the CO ordered emergency deep. When the contact (probably USS Rentz) passed astern and came back on the other side, the CPA calculated out to about 50 yards.

In this case, we don't know if the cruiser was operating a quieting system (some have questioned if discussion of such a hypothetical system skirts the bounds of confidentiality, but we'll assume the commenters are referring to the possibility of a system such as the one described in this open-source Wikipedia article), who was on the 'scope, and what the sea state was. I'm used to the CO or Command Duty Officer (when stationed) always being on the 'scope during a Battle Stations scenario for ASWEXs, but Montpelier might not have that requirement. Another thing to consider is that Montpelier, having recently returned from deployment, is probably on one of her first FLEETEX support missions after likely losing a lot of key players from the deployment to transfer, and is training up new Fire Control and Sonar teams. Alternately, they might have just been coming up for normal comms during a break in the exercise schedule, and, as one commenter suggested, didn't have a good track on the San Jacinto, having either missed a 180 turn or putting one in that didn't exist. (For a quiet target, a zero-bearing rate, decreasing range sonar track looks a lot like a >20K yard contact.) I've been in situations when the seas were high enough coming to PD that I didn't get a good look at one sector until my 3rd or 4th sweep after the optics break the surface -- and who knows, if they had a UI or two on the ship's control party, maybe they had a hard time keeping the 'scope optics out of the water. However, this is unlikely since it was reported that a lookout on the cruiser saw the submarine. I'd be more likely to guess a possible sail broach, with the OOD more concerned about yelling at the Dive to get the ship back down than completing his safety sweep. We really won't be able to have an informed discussion on potential lessons learned until we do know those things -- but, as usual, that shouldn't stop us from holding forth, since that's what us Submariners do.

And for non-Submariners visiting here and wondering, no, Montpelier is not yet one of the submarines with female crew members.

Staying at PD...

Update 1635 16 Oct: The heads of the crawl up their assholes with a microscope investigation boards have been named:
Vice Adm. Michelle Howard, deputy commander of USFF, appointed Rear Adm. Ann Phillips, commander of Expeditionary Strike Group (ESG) 2, as the investigating officer to lead a command investigation into the collision of USS Montpelier (SSN 765) and USS San Jacinto (CG 56).
The investigation is administrative in nature and will look into the cause of the collision and determine any fault, neglect, or responsibility. Additionally, the investigation will identify any shortfalls in procedures and make recommendations for corrective action.
USFF has also directed a Safety Investigation Board (SIB), which will be led by Rear Adm. Joseph Tofalo, commander of Submarine Group (SUBGRU) 10. The SIB will identify hazards and causal factors for the collision, and make recommendations to prevent future mishaps.
I'm guessing they'll find that people on the submarine were doing a lot of things that happen on every single submarine in the world (like the Throttleman cleaning around his watchstation instead of standing straight and monitoring his panel 100% of the time) that will prove that Montpelier was grossly deficient but there are no Force-wide issues, as Montpelier was an outlier. [/sarcasm]