|Commanding officer of USS Montpelier (SSN 765), Commander Thomas Winter, was relieved for the standard reason of "loss of confidence in ability to command"1.
Unofficially, the navy determined that Montpelier's October 2012 collision with the Ticonderoga-class guided-missile cruiser USS San Jacinto (CG 56) resulted from Montpelier's failure to follow established procedure, poor teamwork and human error.
Web: NavyNews, USS Montpelier Commanding Officer Relieved of Duty
1. This is a catchall phrase that covers anything that is viewed as sufficient impediment of ones ability to lead submariner-sailors.
2. The Command-At-Sea pin is worn by the incumbent commander on the right and by the post successful tour commander on the left. What constitutes a successful tour is determined with considerably less publicity than the very public relief, removal, or loss of command. Generally a command tour interrupted or terminated by a removal for cause is not eligible for the Command-At-Sea pin as specified above (MILPERSMAN 1210-170, Command at Sea Insignia: Qualifications).