In the past 14 months, I (and my crews) have flown through STT to do four charters out of TMM. No disruptions to our plans related to the ferries. This is not to say that everything went perfectly smooth every time. Smith's will book you on their ferry and allow you to use one of their competitors if you can't make theirs or they mess up. More fun than sailing up "seasick alley" from Charlotte Amalie.