What does not have weight but is able to let a ship sink?

A hobo who does like to smoke cigars but does not have any money, collects cigars stumps. From every six stumps he finds he can make a new cigar. One a particular day he finds 36 stumps. How many cigars can he smoke on that day?

Who makes it, doesn't tell it.
Who gets it, doesn't know it.
Who knows what it is, doesn't want it.

What is it?