Hailing: A Hail is a meaningful word or string of words capable of being heard in the prevailing conditions by the occupants of the boat to which it is addressed.
This sentence is from a book by Bryan Willis; 2005-2008 The Rules in Practice. Hailing is not a defined term in the rulebook, but this is a useful definition supported by appeal cases. There are only two rules in the book which require you to hail, when you want to use them. Can you name the rules without looking them up?
On the Yachting South Australia website I found an article about it from 2003. As we had a new rule cycle in 2005 maybe some of the finer points are no longer valid, but the general principle has not changed. You can read it here: HAILING - How, When & Why
This article was part of a series of newsletters with News & Information produced by the Racing Rules Committee of Yachting SA. It seems to be discontinued shortly after # 7, which is a pity.
From what I could find, these news items and rules interpretations seem certainly worthwhile to pick up again.
How about it, Bruces?