how to stop turn digital crown to unlock and eject water

Perhaps this guidance can help, if you question is about swimming with the watch?

Unlock your Apple Watch and clear water from the speakers

When you start a swimming workout, your screen locks to prevent accidental taps. You can see the Lock icon at the top of the screen. To use your watch, you need to unlock the screen.

1. To pause your workout, press the Digital Crown and the side button at the same time.
2. Dry your screen. If your screen's wet, the water might cause accidental taps.
3. Turn the Digital Crown to unlock the screen and clear any water from your Apple Watch. Your watch makes a sound, and you might feel water on your wrist.

To lock your Apple Watch again, swipe right, then tap the Lock button. 

Swim with your Apple Watch - Apple Support