yard at Baltimore, Maryland, for conversion to a cable repair ship. She was redesignated ARC-4 and renamed Thor on 14 November 1955. On 3 January 1956, Thor completed her conversion and was recommissioned. Thor was converted to support the installation of the Sound Surveillance System and other defense cable projects. The system and name were at the time classified with the unclassified name Project Caesar being given to the installation and support of the system. Function The ship was principally used to transport, deploy, retrieve and repair cables and to conduct acoustic, hydrographic, and bathymetric surveys under Project Caesar. Civilian specialist are involved during cable or surveying operations for the technical work. The Thor and Aeolus had three diameter cable tanks each with a capacity of about of five inch armored cable or of coaxial cable. Cable being laid was under constant test by civilian experts in the ships cable test room. Cable ships with bow sheaves only required towing astern for some long runs of cable resulting in the unusual feature of two sets of running lights suitable for the stern becoming the effective bow. By the late 1970s the two Artemis class transports converted to cable ships were in need of modernization or replacement. Some shortcomings in design worked against modernization even though two other ships of the same age were slated for major modernization. The class had been designed with a relatively shallow draft of , least draft of the attack transports that had drafts from to . Compared to the draft of the smaller and , designed as an Army cable layers late in World War II and the only Navy ships designed as cable ships, this was a disadvantage in a cable ship's loading and operations. Both of those ships, built the same year and as old, were essentially rebuilt to extend their service life but the two larger ships were not going to be modernized. The shallow draft, which also hindered bathymetric survey work due to shallow transducer depth, and large sail area of the exposed hull and superstructure made stopped or very low speed cable operations hazardous. Thrusters could not be built into the shallow draft hulls and tugs had to be used for some operations. The ships had no stern cable capability and could not effectively be modernized for that capability. Finally, the ships could not carry a full load of cable