(Describer) Under a round logo of a wave, title: Ocean Today.

[fast-paced music]

(Describer) Title: Ship Under a Bridge.

(Describer) A white ship passes under a bridge.

(Describer) A cargo ship goes under the Golden Gate Bridge.

(female narrator) Every day, hundreds of container ships enter and leave U.S. ports, but navigating in and out is tricky business. With shallow waters, ship traffic, and bridges, ports can be a real obstacle course. How does a huge ship actually fit under a bridge? It's not easy.

(Describer) Another cargo ship goes under the Golden Gate.

Ships have gotten much bigger over time. Now deeper and taller, hitting bridge bottoms is an emerging safety issue. When navigating into ports, ship captains monitor real-time data on water conditions, like tides, currents, and winds.

(Describer) The wind blows a US flag and the clouds.

During high tide, there is less room to fit under the bridge. During low tides, a ship could run aground.

(Describer) In a photo, a ship stands in the mud. Another ship's tower just barely gets under a bridge.

To solve this problem, NOAA created the Air Gap system. This tool measures the clearance between the water surface and the bridge. These measurements are updated every six minutes to account for water level and bridge height changes due to bridge traffic, air temperature, and more. This info will tell the captain how much room exists to safely navigate the ship under the bridge. This high-tech tool helps prevent accidents, keeping ships safe and on schedule.

(Describer) Other ships are shown carrying their many containers.

(Describer) Logos are shown for the Smithsonian and NOAA. Accessibility provided by the US Department of Education.

Accessibility provided by the U.S. Department of Education.