Underway replenishment

Underway replenishment is when big boats or ships give supplies to other boats or ships while they are both moving in the water.

Think of it like when you're playing with your toy boats in the bathtub or pool. If one of your boats needs more water or toys, you can't really stop playing to get it. So, you have to keep moving your boats around while giving toys or water from one boat to the other.

The big boats and ships that do underway replenishment are like the big, grown-up versions of toy boats in the water. Just like you have to keep moving your boats while giving supplies, these big boats have to keep moving in the water while giving supplies to the other boats or ships that need them.

The supplies that they give can be things like food, fuel, or even parts to fix broken equipment on the other boats or ships. And since it's hard for boats and ships to stop moving and stay in one place in the water, underway replenishment helps them get what they need without having to slow down or stop.