Any line from the bow should not be long enough to reach the prop. You know its going in the water
at some point. At least at the stern you are there, and can see what's happening.
In the end...the blame game
is a waste of time. Its your boat. You pay. If you can sweet talk the marina into splitting the damage with you, then good for you. But I expect you will never be welcome there again.
I feel your pain. The crane strap was on my prop shaft for haulout, causing major damage. You own a boat, you take the risk. I had to pay. Was not my fault. But if all damage went to the marina, every marina would have to shut down.