The challenge of reloading VLS at sea

Will navies achieve underway replenishment for vertical-launch systems?

Possibly, but it needs new ship layouts and safer transfer systems because missiles are far more delicate than shell ammunition.

Navies have reason to keep investigating at-sea missile replenishment because combat expenditure can empty vertical-launch cells quickly. Missiles are fragile during handling, making top-loading cells in a moving seaway far harder than transferring gun ammunition. One proposed path is a below-deck magazine that receives replacement missiles and feeds the launch cells from underneath. No current ship is arranged around that magazine-and-transfer path, so the concept would require a substantial redesign rather than a new crane alone. Until such systems mature, guns retain an advantage for sustained fire because their ammunition is easier to replenish. Concern over missile expenditure could even encourage destroyers to carry two guns again, although helicopter decks make an after mounting difficult and may push both weapons forward.