U.S. Navy Cruise Missile Submarine USS Michigan Begins 17-month Refit Period U.S. Navy cruise missile submarine USS Michigan (SSGN 727) docked on July 10 to begin a 17-month Extended Refit Period which will end in 2020.

Work during this availability includes battery replacement, structural repair and preservation, shaft replacement, other propulsion plant inspections and improvements, and installation of several new alterations. Critical path work for the ERP will be the structural repairs and preservation of the superstructure and ballast tanks.

Maintenance availabilities are a key element in maintaining an agile and modern fleet that is able to remain on station for long periods, which is especially important for America’s guided missile submarines.

USS Michigan (SSGN 727) docks at Puget Sound Naval Shipyard & Intermediate Maintenance Facility July 10 to begin a 17-month Extended Refit Period. (Photo by Max Maxfield)

The project team is implementing several process improvement initiatives aimed at reducing time to perform steering and diving grooming, hull valve repairs and structural inspections and repairs. The project team and engineering have analyzed each of the work strings to find opportunities to streamline the process.

Michigan is one of four Ohio-class submarines converted from a ballistic missile submarine to a cruise missile submarine. The boat’s homeport is Naval Base Kitsap – Bangor. Built by Electric Boat, she was commissioned (as a Ohio-class SSBN) on 11 September 1982. Its conversion into a SSGN was completed in June 2007.

Ohio-class SSGN

According to the U.S. Navy, Ohio-class guided-missile submarines (SSGN) provide unprecedented strike and special operation mission capabilities from a stealthy, clandestine platform. Armed with tactical missiles and equipped with superior communications capabilities, SSGNs are capable of directly supporting Combatant Commander’s strike and Special Operation Forces (SOF) requirements.

Combined, the four SSGNs represent more than half of the Submarine Force’s vertical launch payload capacity with each SSGN capable of carrying up to 154 Tomahawk land-attack cruise missiles. The missiles are loaded in seven-shot Multiple-All-Up-Round Canisters (MACs) in up to 22 missile tubes. These missile tubes can also accommodate additional stowage canisters for SOF equipment, food, and other consumables to extend the submarines’ ability to remain forward deployed in support of combatant commanders’ tasking. The missile tubes are also able to accommodate future payloads such as new types of missiles, unmanned aerial vehicles, and unmanned undersea vehicles.

The SSGNs have the capacity to host up to 66 SOF personnel at a time. Additional berthing was installed in the missile compartment to accommodate the added personnel, and other measures have been taken to extend the amount of time that the SOF forces can spend deployed aboard the SSGNs. The two forward most missile tubes were permanently converted to lock-out chambers that allow clandestine insertion and retrieval of SOF personnel. Each lock-out chamber can also accommodate a Dry Deck Shelter (DDS), enhancing the SSGNs’ SOF capabilities.

During conversion, each SSGN received the Common Submarine Radio Room and two High-Data-Rate antennas for significantly enhanced communication capabilities. These additions allow each SSGN to serve as a forward-deployed, clandestine Small Combatant Joint Command Center.

BUSAN, Republic of Korea (Oct. 13, 2017).The Ohio-class guided-missile submarine USS Michigan (SSGN 727) (Gold) pulls into the pier of Republic of Korea’s Busan Naval Base as part of a routine port visit. The visit is to strengthen the already strong relationship between the U.S. Navy and the people of the Republic of Korea. (U.S. Navy photo by Mass Communication Specialist Seaman William Carlisle)

General Characteristics, Ohio Class

Builder: General Dynamics Electric Boat Division

Propulsion: One nuclear reactor, one shaft

Length: 560 feet (170.69 meters)

Beam: 42 feet (12.8 meters)

Displacement: 16,764 tons (17,033.03 metric tons) surfaced; 18,750 tons (19,000.1 metric tons) submerged

Speed: 20+ knots (23+ miles per hour, 36.8+ kph)

Crew: 15 Officers, 144 Enlisted

Armament: Up to 154 Tomahawk missiles, Mk48 torpedoes; 4 torpedo tubes

Ohio-class ships converted to SSGN

USS Ohio (SSGN 726), Bangor, Washington

USS Michigan (SSGN 727), Bangor, Washington

USS Florida (SSGN 728), Kings Bay, Georgia

USS Georgia (SSGN 729), Kings Bay, Georgia



