A large warship can still be densely packed, so displacement alone does not guarantee an easy upgrade. The Type 45 destroyer was built with a specific space reserved for a strategic-length Mk 41 installation rather than relying on an accidental void. At the time of the video, that reserved space was instead intended for a Sea Ceptor installation and had meanwhile served as a forward gym. The change in launcher choice does not weaken the design lesson: only the protected volume made a substantial later addition practical. Without it, the navy would have to remove more valuable equipment or accommodation. Upgradeability depends on choices made during initial design, when the eventual system may not yet exist.
Notable Point · 31:11-32:13
Growth margin must be reserved before it is needed
Use the Type 45's reserved launcher space to see how planned growth margin can support a different weapon system from the one first envisioned.