We know from PS, that the boats transport first-years across the lake at the start and end of their school year.
But in a 2007 interview, jkr said that it also transports seventh-years at the end of their last year back to the train station.
OH YEAH, DEFINITELY! THE BOATS WOULD'VE
BEEN THE MOST POETIC AND BEAUTIFUL WAY
TO FOR THEM TO LEAVE, AND SYMBOLIC IN
THAT THEY
HARRY WOULD HAVE SEEN THE
THESTRALS AGAIN. YOU KNOW WHAT I MEAN?
IT WOULD'VE BEEN A RETURN TO INNOCENCE
REALLY, AND PASSAGE OF WATER IS SO
SYMBOLIC, IN HISTORY OF MAGIC. SO YEAH, T
THINK IT WOULD'VE BEEN GREAT.
I really like the idea of how poetic it is, but i think jkr forgot that the boats transport 1st years back too, so i'm not sure there would be enough boats for everyone.
I headcanon that this is a new tradition after the battle of hogwarts, and instead, 1st years take the carriages at the end. Or perhaps there's enough boats for both years?
What are your thoughts?