You can back up in a straight line, if you have a dual-prop boat, and avoid the hazard boaters have long called prop walk, where a single propeller pulls the boat's stern in the prop's direction of turn. Whether your boat is equipped with outboards, inboard-outboard drives or the dual rudders of an inboard, having two propellers that can turn together or turn independently can give you significant advantages over any vessel driven by a single propeller
Improved Maneuverability
A dual-prop boat allows you to avoid the issue of the unwanted sideways movement called prop walk. Two propellers rotating in opposite directions -- the normal rotation for dual-prop boats -- cancel out the forces that pull your boat's stern away from a straight line. You also can use this counter-rotation to cause prop walk deliberately, to move your boat sideways into a cramped parking place, a maneuver a boat equipped with rudders will handle more readily. Dual props also make for quicker, tighter turns and faster stopping, giving you a wider range of control and making your boat more nimble and safer.