[a3n]

Transferring items between ships at sea is not done while "stationary," it's done by both ships underway in parallel.

It's relatively dangerous, both ships have to be designed for it, and both crews have to be trained for it.

I participated in many such refueling and replenishing operations while I was in the US Navy.

https://www.google.com/search?tbm=isch&q=resupply%20at%20sea...

https://en.m.wikipedia.org/wiki/Underway_replenishment