you are correct that it is not one of the required hails. I never intended to state that it was. there are many communications between boats that are not required, but end up falling under the category of good practice. a port boat hailing "tack or cross" is also not required, nor dies it need to be answered, but that doesn't mean that it isn't good practice.I went leafing through RRS and for the life of me, I could not find that as a proper hail. Citation please.
the more competitors know about what each other are thinking, the less likely they are to end up in a protest situation in the first place.