Port and starboard vessel's starboard side by green and its port side by red. Aircraft are lit in the same way. Port and starboard Port and starboard are nautical and aeronautical terms of orientation that deal unambiguously with the structure of vessels and aircraft. Their structures are largely bilaterally symmetrical, meaning they have mirror-image left and right halves if divided long-ways down the middle. One asymmetric feature is that on aircraft and ships where access is at the side, this access is usually only provided on the port side. To understand which is which, when a person is facing the bow on a
Sinking of the RMS Titanic list to starboard was caused by asymmetrical flooding of the starboard side as water poured down a passageway at the bottom of the ship. When the passageway was fully flooded, the list corrected itself but the ship later began to list to port by up to ten degrees as that side also flooded asymmetrically. "Titanic"s down angle altered fairly rapidly from zero degrees to about four and a half degrees during the first hour after the collision, but the rate at which the ship went down slowed greatly for the second hour, worsening only to about five degrees. This gave