CONTROLLABLE PITCH PROPELLERS

STERN WALKS TO STBD

FFG

DD/CG/MCM

DD/CG DEVELOP STERN WAY WHEN TWISTING

DDG 51

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Notes:

REFERENCES: MSI STUDENT GUIDE

Notes:

CONTROL REVERSIBLE PITCH PROPELLERS ALWAYS TURN THE SAME DIRECTION AND THEREFORE SIDE FORCES ARE CONSTANT WHETHER THE SCREW IS GOING AHEAD OR ASTERN.

FFG: RIGHT HAND SCREW FOR ALL BELLS. AHEAD BELLS DRIVE STERN TO STARBOARD AT LOW SPEED. ASTERN BELL ALSO MOVES STERN TO STARBOARD. WASH WILL BE DIRECTED AT THE PORT SIDE OF THE STERN. EVEN AT ALL STOP, PROPELLER CONTINUES TO ROTATE, SO STILL HAVE STERN WALK.

TWIN SCREW (DD-963/DDG-993/CG-47): INBOARD TURNING FOR ALL BELLS (PORT CW/STBD CCW). SIDE FORCES CANCEL EVEN WHEN TWISTING.