If Gangplank's ship exploded, how does his ult work now?

It's from a new ship and a new crew that we've yet to have been told how he gathered up. Burning Tides does end with him having his arm cut off, and next time we see him he's got a prosthetic, put on a bit of a beer belly and got tattoos. We have yet to see how those things came to be, so a new ship and crew isn't out of the question, even if such things aren't on as an impressive a scale as before.

Considering that Gangplank was previously the self-declared pirate king of Bilgewater, I can't imagine it'd be all that hard for the guy to commandeer another ship belonging to one of his subordinates. When a guy that cruel seemingly comes back from the dead, and with a chip on his shoulder to boot, it wouldn't be a wise man who tried to deny him what he wanted.

It takes 5 minutes for Jack Sparrow to get a new ship. Why would it take any longer for our lovely pirate king?

HAD a ship... and he's on gp's enemy list... coincidence? Besides, he could have had multiple ships in drydock for just such an occasion.

Something that really doesn't need explaining.

Well his lore mentions how he stole Swains flagship,so he might use that one now as his main ship.

as far as i know he has 2 ships, the dead pool and the leviathan. the dead pool was just his favorite as it was his own and main ship.

He probably had more ships, like the Leviathan. The Death's Daughter upgrade could also be him so desperate for resources he was willing to take his old cannon back from the depths