Slave Galley
A type of ship powered by a large group of oarsmen, in addition to, or in the place of, sails. The standard image is dirty rowers seated two-by-two down either side of a narrow aisle, like an even-more-sadistic school bus, overseers with whips, and a coxswain with a drum beating out a steady rhythm. Showing a character as a galley slave is a quick-and-easy way to depict their suffering, as it combines all the bad parts of being a sailor with all the bad parts of slavery - that is to say, all of it.
Real-life oar-powered ships were in use from the time of the Pharaohs up through the early steam era, in one form or another. The Viking longship and the ancient Greek Triremes are the best-known examples, but the Triremes had three rows of oars stacked above each other, and the oarsmen were highly-skilled free men. Later designs that relied on multiple men per oar, instead of multiple rows of oars, were crewed by slave labor, but they didn't show up until Renaissance times.
This trope was firmly established by Ben-Hur despite the movie being a good demonstration of why the ancient Greeks and Romans didn't use slaves for war galleys! Poorly treated slaves can't row as fast as professionals, and the ship would be further slowed by the weight of all those chains and whip-wielding overseers. When a ship is in danger of being rammed, the worst thing to do is stop rowing and become a sitting duck, yet that is exactly what the panicky galley slaves do in "Ben Hur", thus converting the threat of being rammed into a certainty.
Film - Live Action
- Most depictions in media are direct references to Ben-Hur; the title character spent a few years on a Roman slave galley.
- The Smokers from Waterworld showed off their cruelty by forcing their crew to move their flagship - a supertanker - by muscle power. This is spectacularly stupid since the supertanker weighs 30,000 tons even before loading any cargo, but Sci-Fi Writers Have No Sense of Scale.
- The undead crew of the Black Pearl in Pirates of the Caribbean used galley oars for a speed advantage. Since the crew were immortal zombies, they could conceivably push to flank speed for hours at a stretch, and still be ready to fight when they caught their prey.
Literature
- Uhtred, the lead character from Bernard Cornwell's Saxon Chronicles, spent a year or so as a slave in the Dark Ages variant of a slave galley. He didn't enjoy it.
- Cazaril's backstory in Lois McMaster Bujold's The Curse of Chalion is revealed to contain two life-changing experiences/epiphanies during his 19 months as a rower on a Slave Galley (three if you cound the circumstances of him ending up on there to begin with).
Real Life
- Servile Galleys actually did come into fashion in the late middle ages(at the earliest). By that time rowing methods that allowed only one trained man to an oar with a large team of backup had been developed.