How old is my great grandmother's ring?

by Del
(Alberta Canada)

I recently received my grandmother's ring which had belonged to her mother and I am wondering where it is from and how old it is. On the inside of the gold band it is stamped with a crown that resembles 2 horseshoes that have been joined. Inside the crown are the letters N and W then beside this is an upright anchor. The stamp is quite small and to see the N and W you need a magnifying otherwise I would have taken a picture. Looking forward to hearing what you have to say.