USS Louisiana marks Navy's last nuclear refueling overhaul for Ohio-class ballistic missile subs

Those living along the shoreline of Hood Canal may have spotted a submarine sailing through the water on Friday. It was the USS Louisiana (SSBN-743), heading back to its homeport in Naval Base Kitsap-Bangor following the completion of its 41-month overhaul.

The Ohio-class nuclear-powered ballistic missile submarine (SSBN) USS Louisiana arrived in Bremerton in August 2019 to conduct an Engineered Refueling Overhaul (ERO) at the Puget Sound Naval Shipyard. ERO is a type of refit to refuel Ohio-class SSBNs' nuclear power reactor and would extend a sub's service life for another 20 years. The Navy conducts EROs at Norfolk Naval Shipyard or Puget Sound Naval Shipyard, depending on where a submarine is assigned, in the 20th year of the submarine’s life, according to Department of Defense's Inspector General report in June 2018.

USS Louisiana was the last submarine of the 18 Ohio-class ballistic missile submarines (four were converted to Guided Missile Nuclear Submarines, SSGNs) to undergo the nuclear refueling process. The first sub to do an ERO was USS Ohio, which was commissioned in 1981 and conducted an ERO from 2002 to 2005.

Among the 18 Ohio-class ballistic missile submarines' EROs, USS Louisiana's 41 months of overhaul was the longest. The USS Maine and USS Nebraska, the last two Bangor-based submarines conducting the process before Louisiana, spent 32 months and 40 months, respectively, undergoing the refueling process at Puget Sound Naval Shipyard.

A list of the 18 Ohio-class ballistic missile submarines and the time to conduct the EROs:

"The Louisiana ERO included 120,000 more resource days of work than the Nebraska ERO, and 150,000 more resource days of work than the Maine ERO. Additionally, the length of Louisiana’s ERO was impacted by the COVID-19 pandemic and unexpected new work items that included an unprecedented repair to a communication system," Puget Sound Naval Shipyard spokesperson Anna Taylor said.

A resource day is one shift worked. The Louisiana’s ERO was the largest repair package in ERO history at more than 870,000 resource days, Taylor said.

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In addition to the nuclear refueling, shipyard workers also overhaul or replace major components within the submarine, upgraded the boat's electronic systems, and configured more living spaces for women on the boat, Taylor said.

In 2010, Secretary of Defense Robert M. Gates lifted the ban preventing women from serving aboard submarines. Ohio-class submarines were required to do habitability modifications to provide separate berthing and sanitary spaces for women submariners. Future Virginia-class and Columbia-class submarines are being built gender-neutral and will not require any habitability modifications, according to the Navy.

With the completion of the ERO, USS Louisiana on Feb. 9 departed the shipyard in Bremerton to conduct sea trials and test the sub's performance and seaworthiness. The boat returned to Bangor on Friday after the general evaluation, said Submarine Group 9 spokesperson Lt. Corey T. Jones.

It is the Navy's plan to replace all its Ohio-class ballistic missile submarines — eight based in Bangor — with 12 new Columbia-class SSBNs. The 14 Ohio-class SSBNs entered service between 1984 (USS Henry M. Jackson) and 1997 (USS Louisiana). Originally designed to serve for 30 years, the Ohio-class SSBNs were later certified for 42-year service lives, consisting of two approximately 19-year periods of operation separated by a midlife engineered refueling overhaul, according to a Congressional Research Service report in January 2023.

The Navy procured the first Columbia-class boat in Fiscal Year 2021 and wants to procure the second one in the class in FY 2024 and the remaining 10 at a rate of one per year from FY2026 through FY2035, according to the report. The Navy plans to begin replacing the Ohio-class boats with new Columbia-class SSBNs in 2031.

SSBNs perform a singular mission of strategic nuclear deterrence and are armed with submarine-launched ballistic missiles (SLBMs). SLBMs are large, long-range missiles armed with multiple nuclear warheads, according to the report.

Previous coverage:USS Louisiana, last of the ballistic missile submarine fleet, to begin refueling at Puget Sound Naval Shipyard

Reporter Peiyu Lin covers the military for the Kitsap Sun. She can be reached at pei-yu.lin@kitsapsun.com or on Twitter @peiyulintw

This article originally appeared on Kitsap Sun: USS Louisiana returns to Naval Base Kitsap-Bangor after overhaul