TWIN / QUAD PROPELLERS FIXED PITCH

COUPLE/SIDE FORCES CANCEL

THRUST FORCES COMPLEMENT

ENGINES OPPOSED ALL FORCES COMPLEMENT TO TWIST SHIP

AHEAD

ASTERN

NOTE: LHA/LHD SCREWS TURN INBOARD

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REFERENCES: CRENSHAW

Notes:

WHEN DEALING WITH MULTIPLE COMBINATIONS OF PROPELLERS, FIXED PITCH PROPELLERS’ SIDE FORCES CANCEL WHEN GOING AHEAD OR ASTERN WHILE THEY AUGMENT WHEN ENGINES ARE OPPOSED.

IF THE SHIP’S PROPELLERS TURN OUTBOARD IN THE AHEAD DIRECTION, THE SIDE FORCE WILL COMPLEMENT THE TWIST.

IF THE SHIP’S PROPELLERS TURN INBOARD IN THE AHEAD DIRECTION, THE SIDE FORCE WILL OPPOSE THE TWIST.