When the sun dips below the horizon while out on the water, familiar surroundings and landmarks disappear and lights of varying intensities and meanings take their place. Accurate navigation, lower speeds, eagle-eye lookouts, and safety precautions become much more critical while nighttime boating. GPS units, chartplotters, radar, thermal/night-vision scopes, and spotlights enhance safety, but nothing replaces the human component when boating at night.
No matter what high-tech navigation equipment is on board, the first rule of night boating is to slow down. Floating objects, like crab pot markers, flotsam, or fixed objects and unlit navigation aids are often hidden until they are very close; running into them can cause severe boat damage or personal injury. At an unsafe speed, the ability to maneuver quickly around these objects or other vessels can become dangerous.
Boaters should know the navigation (running) light requirements for their vessel. Federal law requires that vessels of any size, including rowboats or dinghies, display one or a combination of red, green, white, or yellow lights, which indicate vessel length, as well as purpose and direction of travel. Also, the flashing characteristics of lights affixed to navigational aids, such as channel markers or buoys, should be reviewed.
For a complete explanation, read the Boaters Guide to Federal Requirements for Recreational Boats available online or from the Coast Guard Auxiliary or Power Squadron. Also, every state has boater guides that detail state-specific requirements; many are available online or from the Coast Guard Auxiliary or Power Squadron. Some basic requirements are highlighted below.
- Navigation lights must be illuminated while underway between sunset and sunrise and during periods of restricted visibility, such as rain, fog, snowstorms, etc.
- For most recreational vessels, only the white anchor light is illuminated while anchored or moored; running (red and green) lights are extinguished. NOTE: Helm navigation light switches are configured so that only the anchor light can be illuminated when anchored or moored.
- At all times (day and night), boats are to be operated at reasonable and prudent speeds appropriate to the weather, sea state, and traffic conditions to avoid collisions with underway vessels, bridges, docks, and anchored boats.
- Boats are prohibited from towing skiers from one hour after sunset until one hour before sunrise.
- The operator is responsible for ensuring the proper display of navigation lights.
- While underway, the only lights that should be visible to other boats are the red and green lights and the white stern or masthead light. Douse or dim cockpit and cabin lights while underway so they do not confuse other boats.
Keeping a Lookout on Your Boat
Nothing beats a sharp eye during a nighttime voyage. Maintaining a reliable lookout any time while underway is a challenge, but especially at night or for extended periods. Keep in mind that federal and state laws require a lookout. Many boating accident investigations cite a lack of a proper lookout as the cause. Consider these tips:
- If passengers want to be lookouts, use them! Four (or more) eyes are always better than two.
- As a lookout, of course, using the eyes is critical. But the sense of hearing should also be used since sound travels better over water.
- To deter boredom and enhance efficiency, the operator should assign specific watch sectors around a boat to each lookout (for example, bow or stern, port, or starboard) and throughout the voyage, regularly rotate lookouts to different sectors.
General Night Boating Tips
Preparation, practice, and experience are the keys to safe night navigation. Though not exhaustive, some common-sense tips and rules to help boat operators with night boating are presented below.
- Practice night boating by going out on weeknights or during the full moon or clear, star-lit nights. Enlist the help of a boater with night boating experience and familiarity with local waters.
- Check NOAA and weather reports; note wind direction and speed forecasts, moon phase, sunset time, and storm probability.
- Study navigation aid locations and light patterns, course heading(s), landmarks, danger spots, and depths along an intended course.
- Check navigation lights to ensure they work and confirm red/green lenses are on the correct sides. Have spare bulbs and fuses available.
- Have safety gear (personal flotation devices as well as binoculars, spotlight, and flashlights) readily available.
- Ensure that required sound-producing devices and flares are on board. Check that the flares (federal law requires three) are not expired.
- Protect night vision by using red dashboard lights or a flashlight with a red lens.
- On boats with headlights, use these only for docking or close-quarters maneuvering.
- Swivel or hand-held spotlights can confuse other boaters by overpowering navigation lights or affect the vision of approaching boaters. Never aim spotlights into the helm, bridge, cockpit, or center console areas of other vessels.
When boating at night near commercial vessel traffic, avoid danger by giving a wide berth to any moving combination of green, red, yellow, or white lights.
Using a Reciprocal Compass Heading
The easiest way to avoid danger during a night voyage is to make use of a vessel’s compass by employing the reciprocal heading. To do so takes very little practice and some simple math: take a practice run during the day to the intended nighttime route and note the compass heading from the home port to the destination. On the return trip, set a reciprocal (opposite) heading, which can be easily determined by either adding or subtracting 180 degrees from the outbound course. If the outbound heading is less than 180 degrees, add 180; if greater than 180, find the difference.
How Low Light Affects People
- Nighttime boat operators should be able to discern between red and green colors and to see obstacles, vessel lights, and navigational aids even in less than ideal or adverse conditions.
- It takes the human eye up to 60 minutes to adjust from bright light to the most sensitive state in darkness.
- In low light conditions, human eyes lose most color vision and are able to separate only objects that are either lighter or darker than their background; also, in low-light conditions, depth perception is lost.
- At night, ambient light reflects off the water or mist and can blind or confuse operators.
- Navigation lights of other boats can be difficult to discern from shore lights.
- Eliminate distractions by keeping entertainment devices (stereos, computer games, TVs, etc.) and passenger conversations away from the helm.
No matter what high-tech navigation equipment is on board, the first rule for boating at night is to slow down. Developing an understanding of navigation light rules, the configurations of vessel lights and the flashing characteristics of lights affixed to navigational aids will help boat operators to navigate safely at night.