hardlogic

We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. How can that be possible?
Common Wrong Answers
“The ship is circular”
A circular ship would not allow for the sailors to stand on opposite sides and see each other clearly, as they would be facing away from each other.
“They are using mirrors”
While mirrors can reflect images, the riddle specifies that the sailors can see each other clearly without any additional tools, suggesting a simple positional arrangement.
“The ship is in a whirlpool”
A whirlpool would not provide a stable platform for the sailors to see each other, and the riddle implies a steady situation where both can see each other without obstruction.