Hunter boat users have been urged to be mindful of potential hazards that may be lurking beneath their vessels over Easter as part of a campaign to reduce propeller strikes.
There were 18 propeller strikes on NSW waters over the past five years, including two fatal incidents in the northern region.
In the first incident a man died after he fell from a boat while travelling alone and was struck by its propeller in Swan Bay at Lake Macquarie in November 2014.
In the second incident a boy died after he fell from a vessel and was struck by its propeller on the Williams River at Raymond Terrace in January 2018.
A man was also taken to hospital after he fell from a boat he was skippering and was struck by its propeller on the Myall River at Pindimar in October 2014.
"A strike from a propeller spinning at around 3200 rpm can cause serious injury or even death," Roads and Maritime northern principal manager Sonia McKay said.
"Boat propellers can too easily be ignored because they are out of sight and out of mind."
Ms McKay said boat owners should install an automatic engine cut-off device called a kill switch, which is activated by a lanyard attached to an arm, leg, clothing or lifejacket.
Skippers should also regard the area around the propellers as a hazard zone.
"Being aware of this hazard zone is particularly important for people involved in tow sports like water-skiing and wakeboarding or where powerboats are used near swimmers or children such as during sailing school or surf club activities," Ms McKay said.
The awareness campaign will continue until the end of Easter.