Liner - Cruiser (reverse) - Frigate - Freighter (reverse) - Destroyer, all are types of ships.
"ships that pass in the night" could be the saying of this rebus meaning:
- (simile) Two or more people who encounter one another in a transitory, incidental manner and whose relationship is without lasting significance; two or more people who almost encounter one another, but do not do so.
- (by extension) Things which have no significant connection or commonality.
