it will hit them and hurt them seriously
The threat of manatees is really only damaging your "precious" motor boat... *shakes head in disgust* but the threats to manatees are motor boats, fishing nets, and careless polluting people.
Yes people are a threat to manatees
Boats - propellers kill more manatees than any other predator.
Some manatee calves can be preyed on by crocodiles, alligators and sharks but their only significant predator is man. Recreational boat propellers account for many manatee injuries and deaths.
Manatees do not have any natural enemies. They're only enemy is man. They are sometimes seriously injured by propellers of passing boats. The part of the boat that makes the boat move cuts into the manatee, and people even drive over them. Also, when people pollute the manatees can get killed by the trash. They can eat a soda can or other piece of trash, or get tangled in it, where the manatee cannot swim or maybe even breathe.
boat propellers
One of the most important things to do is observe manatee area signs. When these signs are present, it is very important to cut boat speeds. Manatees are slow moving, and boat motors are their biggest enemy. It is very rare to see a manatee in captivity or the wild (near populated areas) that does not have scars or missing pieces from being hit by the propellers on the motor.
Manatees are gray in color, with the shade ranging from very light to medium. The underbelly of the manatee is generally lighter in color than the topside, which can be a light slate gray. Scar tissue, such as from impacts with boat propellers, is typically darker than normal.
Enforced speed zones in Manatee basking areasCaged propellers on boats
The Florida manatee is often injured by boat propellers, as they often bask just below the surface, and cannot be seen by boaters.
He was killed in a boating incident. The propellers of the boat cut him.
The oars or when a motor is used, the propellers on the shaft sticking in the water.