Are all the pictures of the cast on the boat actual pictures of scenes? Or were they just having fun exploring the set? The other thing is we know the boat has inside rooms. So it is possible that some characters are “in” the boat but will not be shown “on” it.
I don’t see them abandoning SB entirely though, as filming scenes there probably requires a lot less than effort and cost than elaborate sets/make up/costumes/cgi of a fantasy world. Then again, if they are just running around a dense wood, that’s not so bad I suppose.
“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn't. And contrary wise, what is, it wouldn't be. And what it wouldn't be, it would. You see?” -- Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass