The weather gage (sometimes spelled weather gauge) is the advantageous position of a fighting sailing vessel relative to another. It is also known as "nautical gauge" as it is related to the sea shore. The concept is from the Age of Sail and is now antique. A ship at sea is said to possess the weather gage if it is in any position upwind of the other vessel. Proximity with the land, tidal and stream effects and wind variability due to geography (hills, cliffs, etc.) may also come into play. An upwind vessel is able to manoeuvre at will toward any downwind point, since the relative wind then moves aft. A vessel downwind of another, in attempting to attack upwind, is constrained to trim sail as the relative wind moves forward and cannot point too far into the wind for fear of being headed. In sailing warfare, when beating to windward, the vessel experiences heeling under the sideward pressure of the wind. This restricts gunnery, as cannon on the windward side are elevated, while the leeward gun ports aim into the sea or in heavy weather may be awash. A ship with the weather gage, turning downwind to attack, may alter course at will to bring starboard and port guns to appropriate elevations. Ships seeking to evade capture or attack have the advantage being downwind if they are faster vessels or are close to friendly land. The term has had a literary rebirth in the popular seafaring novels of C.S. Forester, Patrick O'Brian and Alexander Kent. One of the last times that weather gage was perhaps a factor in a surface naval engagement was in the Battle of the Denmark Strait in 1941, where the German battleship Bismarck and the heavy cruiser Prinz Eugen held the weather gage over the British battleship and the battlecruiser . Being upwind, the German ships had the advantage that their rangefinders were drier than the British rangefinders facing the spray. The weather restricted the visual range to much less than the gun range. The weather gage is a critical component of aircraft carrier operations. Most carrier aircraft are easier to launch if the aircraft carrier is steaming into the wind to generate stronger apparent winds across the deck that allows for greater lift to be generated at lower actual speeds. The Battle of the Philippine Sea is a notable incident of the advantage of