Just to drop this here - there are examples of ships in recent times that are based on the same hull and engineering design, but are given different class names due to different equipment and missions:
Spruance class Destroyers:
Kidd class Guided Missile Destroyers:
Ticonderoga class Guided Missile Cruisers:
All are built on the same hull and have the same basic engines (LM2500 Gas Turbines) along with many other features. They are not used for the exact same missions and equipped with a different mix of sensors, control systems, weapons etc...