在船上做工以抵偿船费
to do work on a ship during your trip instead of paying for a ticket
He was allowed to work his passage from the port of Perth.
She had worked her passage as a cook on board the ship.
I'll go to America. I'll work my passage.
They worked their passage to Liverpool on the cattle steamers.
From Gdynia, he managed to work his passage on a Polish boat to Sweden.
See also: passage (TRAVEL)