[TomMaine]

Sailing along the coast then, does the distance determine whether it's considered offshore or coastal sailing?

Yes, it does. But the distance is subjective to each person you ask. I wouldn't worry about miles.

I'd set your own limits for what you would consider coastal sailing, based on how experienced you are and how you have equipped your boat.

No one can set the bar or miles off for you or your boat(even though they will). Be conservative and set the bar for your weakest link.

It's pretty safe out there if you take it easy.