The auxiliary crane ships are Military Sealift Command Ready Reserve Force ships that can be quickly available to support military sea transportation needs. These self-sustaining ships are useful in ports that have limited, damaged or undeveloped port facilities.
The ten Keystone State Class ships are conversion crane ships the first of which was completed in 1984 and the last of which was completed in 1997. Five of the ships were deployed to the Arabian Gulf in 1990-91. USNS Gopher State acted as a temporary Army prepositioning ship in 1994.
The auxiliary crane ships are converted container ships with three twin boom pedestal cranes which can lift containers or other cargo from themselves or adjacent vessels and deposit the cargo on a pier or lighterage.