Why VLS reload mechanisms struggle at sea

Could VLS cells tilt up so missiles could be reloaded horizontally at sea?

Such arrangements have been studied, but saltwater-sensitive mechanisms and repairs needed after missile launches make reliable reloading difficult.

Tilting VLS cells for horizontal reloading has been studied, but the moving mechanisms must work reliably in salt water. After firing, some parts of a launcher may also need repair ashore. Cold-launch missiles are described as causing less damage to the installation than hot-launch missiles, reducing its maintenance burden over time. Although cold launch is difficult to develop, that reduction in damage forms part of its cost justification.