Wikipedia
Wetting-down
For the christening of fire engines, see Wetdown. For the ceremonial water salute given to vehicles, including ships and airplanes, see Water salute.
Wetting-down is a raucous ceremony for newly promoted officers observed in the U.S. and Royal navies, and the U.S. Coast Guard. The U.S. Marines, National Oceanic and Atmospheric Administration Corps, and U.S. Public Health Service officers also participate in this custom as homage to their naval heritage.