Not all marine vessels rely on white lights for illumination. Some units, like underwater submarines, use other colors to maximize visibility. This practice can also be applied to covert military operations, as well as discreet patrollers monitoring docks and passageways at night. Why do submarines use Red LED lights?
Transitioning to Darkness
When a submarine is on the surface during the day, it uses normal LEDs or fluorescent tube-style white lights. These luminaries are typically marine grade, offering some form of protection from the ingress of water or corrosive agents (saltwater). Sub operators turn on red light when transitioning to complete darkness. A common configuration consists of mostly red light with very little white light.
Eventually, the control room will be completely engulfed in black. This is to ensure maximum visibility when looking through a periscope. Without a dark room, individuals would be temporary blind looking to a periscope, as their eyes adjust to the nighttime environment. Furthermore, there is a huge risk related to light leakage when using white lights in submarines, even when covers are utilized to prevent light from escaping the vessel.
Why Red LED Lights?
Red light, with a wavelength measurement of 650 nm, provides optimal low-level lighting conditions for marine applications. It is least intrusive on natural, human night vision – without goggles. As a result, less time is wasted on acclimation during nighttime operations. Additionally, human error is greatly reduced when operators are able to clearly see in dark conditions. From a cost perspective, it’s cheaper to install red lights in control rooms, compared to equipping every worker and operator with specially designed goggles. To maximize natural nighttime vision, some sub operators wear a black patch over the eye they use to peek through a periscope.
This practice can also be observed in aviation control towers, movie theaters, observatories and planetariums. Another sector that uses red light is hunting. Like submarines, using red light when tracking or hunting nocturnal animals helps reduce spooking creatures on the field.
This article was provided by LarsonElectronics.com.