system
Given the following post, respond as if you're commenting on Reddit:
human
[Dracula] Why did Dracula slaughter the crew of the Demeter?

He did need the ship to make it to England, and picking them off one by one put that goal at risk. It was only the captain's bravery and tenacity, to lash himself to the wheel cross in hand, that allowed the ship to make the final stretch.

I know he needs blood to survive, but in Transylvania he lives in a desolate castle in the middle of nowhere. I always assumed he could go long stretches without feeding.
gpt
Dracula can't go a huge amount of time without blood; he often goes out into the surrounding villages (sometimes in the guise of a carriage driver) to find victims for himself and his three brides.  After a few weeks without blood, his appearance becomes much older and his power, presumably, is weakened.

It looks like the *Demeter* shipped out on July 6th of 1893 and crashed on August 8th - a journey of over a month.  From the captain's journal, there were only 8 on board - the captain, two mates, and five sailors. The first death appears to have been on July 16th, when the first mate vanished.  At this point, Dracula had gone at least 10 days without blood - likely more, since he was hidden in his box and probably loaded onto the ship a day or more before they embarked.  So we can safely assume that two weeks or so is a big hunger point - longer than that, he may get too hungry or too weak.

After that point, it was probably a bit of a game to him, and also a bit of a calculation.  He'd be weak during the day, and if the sailors were emboldened enough, they could pry open each box of dirt until they found him, and they could cut his head off and throw his body overboard.  So he needed to thin the herd, but leave enough of a crew to keep the ship going until they got close to England.  By the time it was only down to the captain, Dracula could likely have just held him under thrall and forced him to take them into port.  The captain tying himself to the wheel with a crucifix made this impossible, but at least it ensured that they'd make it to land one way or another.