As futile as it sounds, that was the plan.
A while back I read a book called "Destroyer Commander" by Tameichi Hara. It's a great book for anybody who wants a look inside the Imperial Navy in WW2. Anyways he ended up commanding the accompanying cruiser, Yahagi, during the last voyage of the Yamato. My memory is a bit shaky but I seem to recall that he writes that the men stationed at the last fueling point for this ill fated fleet went against orders and gave the Yamato more fuel than what was needed for a one way trip. The couldn't bring themselves to believe that the pride of the Imperial fleet was being sent on a suicide mission. I can't remember if the Yamato's captain knew or not. As it was, it didn't matter since she never made it to Okinawa anyways.