so, NON-asshole, wanna explain to us the forces of catenaries?

Of course you don't want to even try. Obviously, by your statement below, you
don't have a clew of the forces involved. (dumb cluck that you are, you are
not even aware that the math and physics of the for forces on the catenary of
nylon rode is the very same as a chain rode).

What an asshole.
You obviously do not understand why you should pay out 4xdepth of chain.
A little understanding of force vectors then explains why the chain
cannot be pulled tight.