Why warship types disappear and sometimes return

Does a ship type die when other vessels take over its roles?

Ship types fade when another platform performs the required roles more efficiently, but changing technology and doctrine can revive an old function under a new form.

Ship types usually fade when another platform can perform the roles considered necessary more efficiently. That judgment can change, allowing a type or function to return. Almirante Grau is recalled as a gun cruiser that remained in service until 2017, armed with eight Bofors six-inch guns in four twin mountings. A type's departure from the major navies therefore does not establish that it has ceased to be useful everywhere. The disappearance of the cog is treated differently, as technological development comparable to iron hulls replacing wooden ones.