2020, As with previous Dry Docks, the three pitch propellers were removed, overhauled, and reinstalled. Photo: Official USCG Polar Star Facebook
Below is a news release from the Acquisitions Directorate (CG-9). Polar Star spent 19 weeks, almost four and a half months away from homeport in the shipyard. They did pretty much the same thing for the past two years and the plan is to continue to do it for two more years. The Service Life Extension Program (SLEP) is necessary because the Icebreaker (Polar Security Cutter) program has been so long delayed in both initiation and execution.
Oct. 20, 2023 —
Coast Guard Cutter Polar Star undocking in Vallejo, California, after successfully completing phase three of its service life extension program. U.S. Coast Guard photo by LT Louis Simione.
The Coast Guard has completed the third of five planned phases of Coast Guard Cutter Polar Star’s service life extension program (SLEP) as part of the In-Service Vessel Sustainment Program.
Accomplished in Vallejo, California by Mare Island Dry Dock, the work encompassed a 132-day, $15.6M dry-docking evaluation along with service life extension machinery efforts. Annual maintenance accompanied SLEP funded improvements to shipboard equipment and numerous vital system upgrades for fire detection, communications and monitoring water quality.
Polar Star will return to Seattle to commence preparations for the 2024 Operation Deep Freeze deployment. The next SLEP phase is scheduled to begin in April 2024.
The Polar Star SLEP addressed targeted systems such as propulsion, communication and machinery control systems for recapitalization. Major maintenance extends the service life of Polar Star beyond that of its original design. By replacing obsolete, unsupportable or maintenance-intensive equipment, the Coast Guard is mitigating the risk of lost operational days due to unplanned maintenance or system failures. The contracted SLEP work items and recurring maintenance are taking place within a five-year, annually phased production schedule running from 2021 through 2025. Each phase is coordinated so that operational commitments will still be met.
Polar Star is the Coast Guard’s only active heavy polar icebreaker. The Coast Guard is investing in a new fleet of polar security cutters that will sustain the service’s capabilities to meet mission needs in both the Arctic and Antarctic regions.
For more information: In-Service Vessel Sustainment Program page and Polar Security Cutter Program page.
Chuck Hill's CG Blog 
I had a tour of the Polar Star several years ago and the tales of tired equipment was a continuous and to me troubling that the CG had let the ship deteriorate quite a bit – so good that the ship is getting some important and long overdue upgrades to replace the tired 1970’s equipment and related stuff. Bit late but good
Considering the propensity of operating aged vessels well beyond when others would decommission, I’d think all future CG ship designs should incorporate as much modularity and access for cheaper/easier future fixes/replacements/upkeep in a cheaper/more efficient manner than dry-docking. (I’m particularly thinking of how the Healy had to have a massive part of the hull cut away while in dry-dock to exchange a main engine, but this kind of evolution with the Polar Star is another example.) And it’s not just the Icebreaker fleet which soldiers (soldiered) on well past when they should have been replaced…. (Storis, Acushnet, many examples in the black hulled fleet, and so on.)