In many rescues, you need a safe and fast way to cross fast moving water. Establishing a safety line is often the best way to accomplish this goal. Rescues in difficult drops often require a line across the river/creek for safety. Another use for a line across the river is a snag line for foot entrapment. If the current is fast and the river is wide, getting a line across can sometimes prove to be very challenging. It is usually well worth the effort though because you can easily transport gear and people back and forth relatively safely. The line can also provide enough support for rescue work or assist in keeping a victim's head out of the water buying you a great deal more time.