That does rather depend on your group, of course.
A few day ago I've played with a complete new group, so with explaining it took us 4 hrs. But I've to say that we've been six people (it was getting a little crowded...) and we have rushed through the Voyage Phase, since it was getting too late for some of them. Therefore no big Sea Event...
With an experienced group of four I'd guess about 1 1/2 up to 2 1/2 for the adventure phase and 1/2 - 1 hrs for the Voyage Phase.
Hope that helps...
Yes, that estimate sounds about right. Our first few two player games (with allies) took around 2 hours each. This was just for one Adventure Phase. The Voyage Phase takes less time but is just as exciting.
It's not the kind of game you would want to squash into 60 minutes.