Is "ahoy" a common exclamation?
"Ahoy" is a traditionally a signal word used to call to a ship or boat. However it can also be used as a greeting, a warning, or a farewell, which is how Erica is using it here. As this show is set in the 80s it may have been a very common/popular phrase then. I would say that in modern days it is not something you will hear often. Ex: Ahoy there. What have you been up to? Ex: Ahoy guys. It's been a long time.