I hear ya…
But if your PC’s don’t want to go on a dangerous ship, then you might not be playing Pirate Borg.
In all seriousness, I think you’re on the right track. I mainly just wanted to create an insane one shot where the effects of ash could not be ignored, but to your point, the PC’s do need to want to get on the ship. So if your PC’s need some motivation, the ash - or taking control of the ash operation - in exchange for forgiving a debt sounds like a great idea. I can also imagine a situation where a small group of desperate/abandoned pirate PC’s at sea have nothing to lose so the potential of gaining valuable resources would be too tempting to refuse.
I temporarily set the price to $0 if you wanna grab it just in case the right situation arises and you wanna give it a go.