Avoid   Motor / Propeller   Strikes

You should always know your approximate location by chart, GPS, or local knowledge. A knowledge of your position allows you to avoid motor/propeller strikes and possible damage to your vessel's propulsion equipment and your ability to control your vessel.   A depth meter is an essential piece of equipment on larger vessels.

Be on the lookout for floating debris which can damage or wrap around propulsion equipment.

Take care that dock lines and other boat equipment are properly gathered and stowed while underway.  A dock line or piece of clothing can wrap around a propeller and disable the ability of the operator to control the vessel.   Dock lines should be of a length sufficient for the docking operation but not so long that they can easily reach back to the propulsion unit.   If towing a tender or zodiac near the propulsion unit use short floating polypropylene towing line(s).

Be extremely cautious when persons are close to the propulsion unit while it is operating.  When re-boarding from the water it is advisable to place the engine in neutral.   The same practice should be observed when recovering a person overboard.

Divers can be critically injured from motor/propeller strikes if you venture tooclose to diving operations.   Stay well clear of diving operations.

Diving Operations

Keep your distance from divers below the surface.   Slow down and proceed with caution, staying as far away as practical while your vessel passes by the diving operation.

Diving operations are identified by flags.

Divers’ boats will display the international blue and white Code Flag Alpha.


A red flag with a white diagonal stripe may also be carried on a buoy that marks the area where diving is in progress, although divers may stray from the marked area.


The wake from your boat, along with weather and other factors can make it hard to see divers’ bubbles on the surface of the water, so reduce speed when you are in the area of diving operations.

If you decide to go diving from your own boat, remember to display the flags described above. Best practice includes staying within 100 m (328’) of your "diver down" flag.