Highly congested docks and waterways are filled with drawbridges that connect various land-based locations around the region. US lighting regulations under 33 CFR 118.1, requires such structures to be illuminated during operation.
This article dives into specific lighting guidelines for bridges over bodies of water where marine operations are conducted on a regular basis.
Types of Lights for Marine-based Bridges
The type of lighting systems applied to drawbridges depends on the classification of the structure. For single-opening drawbridges, every draw span of the structure must be illuminated with two lanterns.
When the bridge is closed, it showcases two red lights; and when open, the bridge displays two green luminaries. During installation, both types of bridge lamps should be mounted at least 15 feet from the roadway (above the bridge). Yellow lights are utilized when illuminating a floating swing bridge.
Signaling Drawbridge Operators with Lights
When a vessel approaches a commercial bridge, the boat operator is required to signal its presence to the drawtender (operator of the drawspan, which can be a trained crew member).
This action is emphasized using boat spotlights. Specifically, 33 CFR 117.15 indicates that a fixed or flashing light is suitable for signaling (white, amber or green). The lighting signal is designed to acknowledge the request from the boat operator and to verify that the bridge will be raised for the safe passage of the vessel.
When the bridge cannot be opened, due to obstructions or busy operations on land, the drawtender must also signal the boat. The lighting signal used for this type of action is a fixed or flashing light (red). Moreover, this signal should be deployed within 30 seconds after the visualization of the boat’s opening signal.
The same signaling protocol is used when the bridge is open and must be closed immediately due to an emergency.