If you want to make a physics rope, it will take several segments of rigid bodies attached by Joints. Currently your best bet would be the HingeJoint.
I recently worked on a Unity-powered game where we had a chain/rope-like string of objects that trailed behind the character and that was the class we used to tie those rigid bodies together.
I'm going to be honest, this is a pretty intricate task and there isn't really an easy way to implement this - especially the winding/unwinding functionality.
My personal advice is this - fake it as best you can. Unless the entire game is solely about the most realistic crane ever built, just fake it.
Judging by the bottom-left image (stick man "platforming" on the crane) Correct me if I am wrong, but I'm guessing that you are making a platformer of sorts.
When it comes to production you want to look at a cost-per-component ratio. You want the most important features, like your controls and other main game mechanics to have the most time/money invested. If something is rather minute in scope, insignificant in the grand scheme of things, investing so much time as to create absolute real-world physics is going to blow the cost/value of component ratio way out of proportion.
It's really up to you to decide how important any component of the game is, but a rule of thumb I use is how often any one component appears in the game. If you've got 1-2 cranes in a level - not so important. Again, if the crane is the entire game, essentially, disregard what I said, use the HingeJoint class, and I will eat my hat.
In the scenario where it should just be faked, I would do it using animations and coordinated/synced interpolated collision geometry to achieve a "good enough" product.
Sorry for the length, hope this helps.
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