why do tug boats spray water

Tugboats spray water mainly as part of a ceremonial tradition called a "water salute." This is done to celebrate or honor a ship's arrival, departure, or special occasion such as a new vessel's first voyage or the retirement of a ship. The water spray comes from water cannons installed on tugboats, originally designed for firefighting and practical uses like cleaning the boat or cooling engines. Besides the ceremonial use, these water cannons can also be used to fight fires on ships or in ports if needed. The spectacular water displays are sometimes synchronized among multiple tugboats, and occasionally colored dyes are added for a more striking effect. This practice originated in the US around the 1950s and is a maritime sign of respect and celebration similar to airport water salutes for airplanes.