We have 2 300foot lines, each stored in a mesh bag. We don't use a stern line that often, so these are stored under our dinghy
on the front deck
. When we are using them (when we sailed around New Zealand
and in the Fiords we used 2 stern lines almost every anchorage) we put the bags midships, just inside the shrouds. The lines feed out easily and then just get dumped back into the bag when done.
This also makes it easy to run the line around a winch. See: Equipment Page 2