In the Northeast US the moorings usually have a heavy pennant attached, with or without pickup sticks -- vertical
fiberglass whips with weights and floats that are easy to grab from the boat (wear gloves, or you risk
fiberglass splinters).
Similar to the Wichard
mooring mentioned hook mentioned above, I carry Grab n Go hook made be CS Johnson for those rare times when we need to attach to a ring.
Grab n Go Hook . It is only rated 700 pounds SWL so I use it just to get attached, while we launch the
dinghy so a more permanent attachment
bridle can be made. The Grab n Go hook works very well clipped to a boat hook. We do carry our own bridal with heavy shackles and thimbles, and fenderboards, so we can tie up in almost any situation.
Someone else mentioned above that you should be wary of moorings unless you know it has been well maintained and is sized appropriate for your boat. +1 on that! The image below is from a
mooring that put a friend's boat on the rocks, causing over $60k (USD) in damages plus
legal expenses. It could have been a total loss if not for the local 3rd party assistance that was rendered to save the boat.