- It is a sailing ship, not a steamship.
- The second mast aft of a sailing ship with three or more masts.
- A sailing ship, such as a schooner, with a fore-and-aft rig.
- A sailing ship with from three to five masts of which only the foremast is square-rigged, the others being fore-and-aft rigged.
- Turbines turned by steam power; a sailing ship driven by wind power.