Uniform State Waterways Marking System - Part 2
![obstruction marker](https://assets.kalkomey.com/boaterexam/images/fm/navrules/uswm-obstruction-marker.png)
Obstruction Marker
Indicates an obstruction to navigation. Do not pass between this marker and the shoreline.
![mooring marker](https://assets.kalkomey.com/boaterexam/images/fm/navrules/uswm-mooring-marker.png)
Mooring Marker
Used for mooring or securing vessels; be aware that a vessel may be secured to such a marker. This is the only marker that a boat can legally be tied to.
![safe water marker](https://assets.kalkomey.com/boaterexam/images/fm/navrules/uswm-safe-water-marker.png)
Safe Water Marker
Indicates safe water. This marker is used to indicate land falls, channel entrances, or channel centers. It may be passed on either side.
Diving Marker
A diving marker or flag indicates diving activity in the area. Particular care must be taken when boating in waters where there are divers. A vessel engaged in diving must display a blue and white flag. A red and white flag carried on a buoy is used to mark areas where diving is in progress, although divers may stray from the boundaries of the marked areas. As a general rule, stay at least 150 feet from any diving flag or activity. Consult your state boating requirements for state-specific diving requirements.
![diving marker in water](https://assets.kalkomey.com/boaterexam/images/fm/navrules/uswm-diving-marker.png)
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