Interestingly there is a semi-successful modular system called StanFlex [0] that the Danish navy developed in the 80s, and now uses for all their ships. "each

Interestingly there is a semi-successful modular system called StanFlex [0] that the Danish navy developed in the 80s, and now uses for all their ships. "each [StanFlex] module is housed in a stainless steel container measuring 3 metres (9.8 ft) in length, 3.5 metres (11 ft) in width, and 2.5 metres (8.2 ft) in height. ... Modules are usually installed and replaced by a 15-ton capacity mobile crane.[3] A module can be swapped out and replaced within half an hour, and after system testing completed, the ship is ready to deploy within a few hours." There are modules for Surface,Air,Submarine, and anti-mine, storage and ELINT, among others [0] https://en.wikipedia.org/wiki/StanFlex https://en.wikipedia.org/wiki/StanFlex