Dry docking for repairs is a regular and important part of preserving any ship's life.
Ships typically are dry docked once every five years when in commission.
The Blueback had not been dry docked since its last dry dock in July 1985. The boat was decommissioned on October 1, 1990. On September 14, the submarine was towed by tug boat down the Willamette to Cascade General Portland Shipyard, where she was in dry dock, or lifted out of the water and placed onto blocks for inspection and repairs to her hull. The Blueback returned to OMSI by on November 17, 1998. OMSI would not otherwise be able to provide for the much-needed dry docking, which took 5,000 labor hours to complete.