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Identifying waterway markers

Boating in Wisconsin

There are two main types of waterway markers designed to assist boaters in navigation and accident prevention. "Regulatory buoys" are designed to identify areas with speed limits or where boats are not allowed. "Navigation aids" are designed to identify lanes of navigation or "channels." It is important that boaters be familiar with each of these buoy types and the message each one conveys.

For safety reasons, except for an approved mooring buoy, no person may moor or fasten any vessel to a regulatory buoy or aid to navigation. It is unlawful for unauthorized people to move, remove, molest, tamper with, destroy or attempt to destroy any waterway marker.

Regulatory buoys.

All regulatory buoys are white with a single orange band at the top and bottom of the exposed buoy. The control symbol is spaced between these bands and is also orange in color. Any wording or message will be in black letters.

Boats Prohibited Buoy.png   

BOATS KEEP OUT: This buoy is signified by a cross in the center of an open diamond. Boats Keep Out buoys mark areas where vessel operation is prohibited. Typical areas for these buoys are swim beaches and dams.

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DANGER: This buoy is signified by an open diamond. Danger buoys mark areas that are hazardous to vessel operation. Typical areas for these buoys are submerged rocks or shoals.

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CONTROLLED AREA: This buoy is signified by an open circle. Control buoys mark areas where vessel speed or wake is controlled for safety purposes. Some control buoys may limit water skiing or other activities. Typical areas for these buoys are around boat launches and other congested areas.

NOTE: "Slow-no-wake" is a common message on controlled area buoys. Slow-no-wake means that speed at which a boat moves as slowly as possible while still maintaining steerage control.

Boat Info Buoy.png INFORMATIONAL: This buoy is signified by an open rectangle. Informational buoys convey messages other than danger, control or restriction, which may contribute to health, safety or well-being.

Aids to navigation.


RED BUOY (NUN): Marks the right side of the channel when travelling upstream.


GREEN BUOY (CAN): Marks the left side of the channel when travelling upstream.


BLACK & WHITE VERTICAL STRIPES: Marks the center of the channel. Pass closely on either side.

Mooring buoys.

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Mooring buoys are white with a blue band and are spherical or ovate in shape.

Signal flags.

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SCUBA DIVERS FLAG: This red flag with a white diagonal stripe means that dive operations are underway. No vessel may operate within 100 feet.

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DISTRESS SIGNAL FLAG: This orange flag has a black square over a black circle. It is the duty of any boat operator observing such a flag to stop and render aid. This signal shall not be displayed unless assistance is needed.

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ALPHA FLAG: This blue flag with a white vertical stripe on the left edge means that the vessel has personnel and/or equipment in the water and is unable to maneuver. Do not approach. Maintain a distance of at least 100 feet from vessel and watch for divers.