I saw this phrase in this webcomic: http://explosm.net/comics/3932 . From the context I guess it means "long time ago". I couldn't find anything about this on the web except a book with the same name(http://www.amazon.com/When-Boats-Were-Made-Steel/dp/1491015179). Is this a reference to the book, or an english saying? What does it mean exactly?
Thanks in advance.