We can even engage in idle speculation; maybe the author uses “boat” to make the situation feel easier to grasp. A boat being stuck sounds like it has less consequences than a ship being stuck.
"ship is stuck" alliterates better, and sounds more childlike, to me at least.
There is no end to that game though, so perhaps it's not worth playing. "buffaloed boat is beached"
I think the alliteration of "big boat" is superior.
That super ship is still stuck though.
Big boat bottomed out becoming barrier that blocks brother big boats! Bodes badly for bearing boxes between big bodies of water!