As viewed from the aft position [towards the fore].
Left-hand propellers rotate counterclockwise on the shaft, while right-hand propellers rotate clockwise on the shaft.
Similar to screwdriver handedness.
A right-hand
propeller rotates like a right-hand threaded fastener will screw into a hole.
Three methods of determining handedness of a screw
propeller:
First Method – Blade Angle on Hub
Identify the
parts of your impeller – there will be 3 blades and a hub
1. Place blade flat on table
2. Observe the hub from a side angle to determine which way the blades are running
3. If blade angle runs from top left to bottom right it is a left-hand propeller
4. If blade angle runs from bottom left to top right it is a right-hand propeller
Second Method – Palm Demonstration
1. Place the hub of the propeller in the palm of your hand
2. Relax your thumb
3. If your thumb lies comfortably on the blade in your left hand it is a left-hand propeller. You can do the same with your right-hand. If your thumb lies comfortably on the blade in your right hand it is a right hand propeller.
Third Method – Flow of Material
1. With a clockwise rotating shaft a left-hand propeller will direct your material flow downward. A right-hand propeller will direct your material flow upward.
2. A counterclockwise rotating shaft will produce the opposite flow results.
Also very similar to whether one's Mickey Mouse hat's ears are lefty or righty.
Bon voyages.