Why down the marina dock?
Many places have a wall or commercial dock , where the chain could simply be dumped (with a rope tail and buoy) so you could simply winch ai aboard.
Hopefully it fits the chain drum.
I used the back the pick-up under bow roller, and winch it aboard. Did have to lift the bitter end to the windlass, and secure it in locker, but did not raise a sweat.
I still think the $200 I gave a couple of folks hanging around the dock looking for work was the easiest, fastest method.
Then I laid it all out on the dock and painted the chain white every 20 feet, then bright orange every 100 feet.