Ship stowaway Ben cursed and made like an angel

There was this book I read and really liked back in elementary school, but then I loaned it to one of my teachers I really liked and never got it back, and I can't recall what it's called or who it's by to get another.
In the first part of the book, Ben (and his dog?) hide on a ship that might be sailing across the Atlantic but is definitely going far. He might end up becoming friends with the cook? I think he may have come out of hiding at some point, but I'm not sure. Things get bad on the boat, and the crew do something (eat an albatross? Or maybe I'm just pulling that from the Ancient Mariner--although the fate of the ship is rather Mariner-esque.) that causes them all to be cursed. The boat is cursed to sail the seas forever (floating above the water?) and the crew to stay on it forever (plus something else that was nasty?) Ben, however, had nothing to do with the bad thing, and the whoever-it-was that cursed the crew alters his curse slightly to be a blessing in disguise. He'll live forever, too, but he doesn't have to stay with the ship. He can roam the world doing good deeds like an angel.
In the second part, Ben changes his name to Neb (and his dog, if I'm remembering correctly that he has one, has his name likewise reversed) and wanders around doing various things and having a few adventures. In one of them, he was helping out with a scavenger hunt type thing (were they looking for an old map, the whereabouts of which had become long lost?) that involved a half-buried milestone, a well, and a lump of lard that was waterproofing something, I think. Along with other things. I remember thinking the milestone was pretty neat, the way they involved that.
I'd given up on finding it again. It would be really neat if I could.

Sounds like Castaways of the Flying Dutchman.

By Brian Jacques. There's also a sequel;

The Angel's Command (Castaways of the Flying Dutchman)

I never thought I'd find this book again! Thank you!