How do I transfer pictures from my iPhone 6 to my Mac while phone is water damaged?
If your iPhone has trusted your Mac, turn your iPhone on, plug it into your Mac using an USB cable, start the application Image Capture and from there you can import all your photos.

I have tried now on my iPhone and does not ask me to unlock my phone or any other stuff like that. 

I guess the only condition is that your iPhone has been connected to your Mac in the past.

Please let me know if that worked for you.