I grew up in Oregon, pronouncing it boo-ee. The two are kind of interchangeable, I think. In context, everyone knows what you're talking about. Doesn't seem important to me.

At least one of my dictionarys gives it as 'boo-e', alternately as 'boi'.

There is a restaurant in Depoe Bay (Hey, Art!) whose rest rooms are marked 'Buoys' and 'Gulls'.