Boaters have a responsibility to the environment. what is one of the three rs?

The three Rs in boaters' responsibility for the environment are: Reduce, Reuse, and Recycle

Since you asked me to explain one of them, I will explain the "reuse"

Boaters have the environmental responsibility to only carry reusable items (such as plates, cups, or silverware) when they're sailing. This will prevent any form of waste from being thrown out into the water.