Mike Baron, U.S. Coast Guard Boating Safety Division
In just minutes, fog, heavy rain and even snow can reduce visibility on the water to just a few yards, leaving boaters confused as to their position and what obstructions may be around them. At sunset, recognizable shoreline features disappear, often replaced by unfamiliar and confusing lights that leave many boaters disoriented and unsure how to get home safely. At night, depth perception and color recognition are impaired. Other boats may be operating without lights, in violation of federal law requiring navigation lights from sunset to sunrise and during periods of restricted visibility. Without lights, boats can be very difficult to see on the water.
Operating a boat when visibility is restricted increases the risk of hitting fixed objects in the water and colliding with other boats. That’s why it’s prudent to lessen your risk by taking preventive action that includes slowing to a safe speed, energizing your navigation lights and sounding the appropriate sound signals for your vessel type, as required by the Navigation Rules, available online through the Coast Guard Navigation Center at navcen.uscg.gov. It is also important to post responsible lookouts who will use all of their senses to determine what lies ahead in time to avoid an accident. A lookout should scan 360 degrees, as accidents at night can occur when a vessel is overtaken from behind.
Illustrations and descriptions of the specific lighting requirements for every type of watercraft are provided in the Navigation Rules, which should be your primary source of information. Briefly speaking, however, these are the navigation lights required for recreational vessels (see yellow box).
Sidelights: These red and green lights are visible to another vessel approaching from the side or head-on. The red light indicates a vessel’s port side, the green the starboard side. These lights are also referred to as combination lights when displayed on a vessel’s bow, or, in the case of a sailboat, when on top of the mast.
Stern Light: This white light can be seen from behind or nearly behind the vessel.
Masthead Light: This white light shines forward and to both sides and is required on all power-driven vessels. Since a masthead light must be displayed by all vessels when under engine power, the absence of this light indicates a sailboat under sail.
All-Round White Light: On power-driven vessels less than 39.4 feet in length, this light may be used to combine a masthead light and stern light into a single white light that can be seen by other vessels from any direction. This light also serves as an anchor light when sidelights are turned off.
Remember that displaying the proper navigation lights at night and during periods of restricted visibility is only half the issue. You also need to be able to identify and interpret the navigation lights you see on other boats.
After dark, the painted color patterns of Aids to Navigation are generally replaced by a configuration of lights. You will need to be able to identify these navigation aids to help determine your position and stay out of dangerous situations.
To get an accurate position, use a nautical chart. The chart will show you the position of the Aids to Navigation, their light characteristics and what landmarks you may be able to see and identify once the sun goes down.
In addition to navigation lights, the Navigation Rules require all vessels to carry sound-producing devices for use during meeting, crossing and overtaking situations. Sound signals are also required during periods of reduced visibility to make other boaters in the area aware of your relative position and the status of your vessel; for example, a power-driven vessel under way and making way is required to sound one prolonged blast at intervals not to exceed two minutes.
Is it easy to get lost or disoriented when visibility is limited? It is. Things look very different at night, which can be stressful for inexperienced boat operators. Expect the unexpected. Practice good risk assessment when deciding whether to boat in the dark. Make sure your required safety equipment is on board, including visual distress signals, and that everyone is wearing a life jacket. Take a boating course through your local Coast Guard Auxiliary, United States Power Squadrons or state boating authority, and educate yourself on best practices for boating at night.
Boating in the Fog
Fog can develop very quickly and brings an increased risk of collision. In fog, if other boats can’t see you they need to hear you. If you see fog moving in, do the following before your visibility becomes seriously reduced:
1. Fix your position on a chart or mark it on an electronic plotter.
2. Reduce your speed to the point where you can stop your vessel in half the distance you can actually see.
3. Turn on your navigation lights.
4. Instruct any passengers to help you keep watch – by sight, sound and smell preferably in the bow.
5. Begin sounding one prolonged blast on your horn (four to six seconds) every two minutes while under way and making way, and two prolonged blasts every two minutes when under way and stopped. Continue until the fog lifts and visibility significantly improves.
If you decide to anchor your vessel and shut off the engine, the sound signals change. While you are at anchor, you must rapidly ring your bell for five seconds at intervals of not more than one minute. This lets other vessels know where you are and what your status is.