Aids to navigation serve much the same purpose as highway signs. Aids such as buoys, signs, lights and beacons are designed to assist boaters by marking hazards and safe channels, helping determine location, controlling traffic and protecting resources. A variety of colors, shapes, lights, numbers and symbols give each navigation aid distinct characteristics. On charted waters these characteristics enable a boater to locate the aid on a nautical chart, a road map of the waterway, and then determine their position.

A boater can learn much about using navigation aids to operate safely. The following is only an introduction to some of the most common aids. Ohio operating laws require a boater to be familiar with and obey the buoys of the Uniform State Waterway Marking System.

Uniform State Waterway Marking System

This system is used mainly on inland lakes but may also be found on federal waters. The system was developed so boaters traveling to lakes in various states could become familiar with one standard system. Channel markers are red and green to match the federal Lateral System. Regulatory markers are white with orange markings and may be on buoys or fixed signs.

Channel Markers A harbor or marina entrance or a dredged channel may be marked to indicate the deeper, safer channel. When going upstream or into a harbor from open water, the right side of the channel is marked by red "nun" shaped buoys with even numbers and the left side is marked by green "can" shaped buoys with odd numbers. If a channel or harbor entrance is lighted, a red light will be on the right and a green light on the left as you enter the channel from open water.

Coast Guard Channel Markers adopted for use on all state waters

Regulatory Markers

	Controlled Area A circle is the most common symbol used on Ohio waterways and usually regulates operation in the area. The buoy or sign will indicate the nature of the controlled area such as No Wake, Idle Speed, Speed Limit, Ski Zone, Open Zone, Speed Zone, etc.
	Information A square is used on buoys or signs giving directions to facilities or other information about the area.
	Boats Keep Out A diamond shape with a cross means boats must keep out. A buoy or sign may show only the symbol or may also indicate Swim Area, Beach, Keep Out, No Boats, Closed Area, Dam, etc.
	Danger A diamond shape is used to mark a hazard to boaters. The buoy or sign may also indicate the nature of the hazard such as Rock, Stump, Shallow Area, Reef, Shoal, Dam, etc.

Not all hazards will be marked by a buoy or sign. Usually only hazards near high traffic areas are marked. Water levels on many lakes may rise or fall several times during the year which changes the location of shallow areas or exposes rocks or stumps which had been in deeper water.

	Mooring Buoy A white buoy with a blue horizontal band indicates a mooring buoy. This is the only type of buoy to which a vessel may be legally tied. However most mooring buoys are private or are rentals and permission is needed to use them.
	Diver Down: Stay Clear 300 feet A red flag with a white diagonal stripe indicates that divers are in the area. A blue and white "alpha" flag is displayed by a vessel tendering a dive operation. Ohio law prohibits operating a vessel within 300 feet of a diver's flag unless tendering the dive operation.

The Lateral System

This system is used on federal waters such as Lake Erie and coastal waters. The Ohio River uses a very similar system with some slight differences. The majority of these aids are used to direct traffic through safe channels. When traveling upstream or into a harbor from open water the right side of a channel is marked by red buoys, lights and daymarks with even numbers. The left side of a channel is marked by green buoys, lights and daymarks with odd numbers. Mid-channel is marked by red and white vertically striped aids. Remember the phrase "Red Right Returning," and keep the red markers to your right when returning from open water or traveling upstream.

Channel Markers

PORT SIDE Odd Numbered Aids	PREFERRED CHANNEL No Numbers--May Be Lettered	STARBOARD SIDE Even Numbered Aids
MID-CHANNEL or SAFE WATER No Numbers--May Be Lettered