Overhaul

Overhauls are considered a comprehensive program to modernize individual ships within a class to new standards for that class and tend to be an extensive process. For example, the Enterprise explorer (UESF) saw a class-wide overhaul where a secondary hull was added, creating the Columbia subclass (UFP Star Fleet). More recently, the Constitution class saw a major upgrade that involved a two-year drydock period for the lead vessel (USS Enterprise), resulting in significant hull and system changes. Overhauls can take anywhere from two months to two (or more) years. Ships will go “cold core” for the duration of the process.