Final answer:
The term 'man the rail' refers to a ship's crew lining up at regular intervals along the edge of the weather decks, often for ceremonial purposes or to show respect when entering or leaving port.
Step-by-step explanation:
The term for lining up a ship's crew at regular intervals along the edge of the exposed weather decks is called “lining the rails” or “man the rail.” This practice can be for ceremonial purposes or during times when the ship is entering or leaving port, and it serves to show the crew's respect for a dignitary or another ship. The crew members stand evenly spaced along the ship's side, presenting a formal appearance.
In historical contexts, this act might occur during pivotal moments, as seen in naval engagements where the aesthetic of a ship and ostentation of its crew played a role in the psychological aspects of warfare. Ships of the line, for example, could form an imposing image before an engagement, their crews “man the rails” to display discipline and readiness. The tradition continues in modern navies as a sign of respect and order.