The US Navy’s Ohio-class nuclear-powered guided-missile submarine (SSGN), USS Michigan (SSGN 727), has completed an extended refit period (ERP).

The refit work was undertaken at the Puget Sound Naval Shipyard & Intermediate Maintenance Facility (PSNS & IMF) in Bremerton, Washington.

The 17-month extended refit work on the submarine started in July 2019, around four months before the beginning of the Covid-19 pandemic.

The work involved structural repair and preservation, battery replacement, propulsion plant inspections and improvements, installation of several new alterations, and shaft replacement.

Additionally, the ERP included structural repairs and preservation of the submarine’s superstructure and ballast tanks.

According to USS Michigan project Operations Department assistant project superintendent Melissa Kittrell, the project team undertook a wide range of modernisation and maintenance works on the submarine.

The broad work package allowed the project team to exercise new tools and procedures to ensure the operational safety of the crew and ship.

Kittrell said: “We had the first availability to try out new equipment developed by Naval Undersea Warfare Centre Keyport.

“This allowed the project to more efficiently conduct some repair work and saved two weeks to the project timeline.”

Kittrell added: “I want to give a special shout out to the Shop 38 Engine Room crew under the leadership of supervisor Josh Fernandez for their dedication.

“They helped Ship’s Force with last-minute issues to get them underway.”

USS Michigan was the second of three submarines that were converted into Ohio-class ballistic missile submarines by the US Navy.

After undergoing extensive reconfiguration for three years, the conversion was completed and Michigan was returned to service as a guided-missile submarine in June 2007.