航海英语 航海英语 the rudder.ppt

Chapter 2 / The Rudder Ch2. Forces acting on the ship / Straight course Ch2. Forces acting on the ship / Rudder to Sb Ch2. Phase one of evolution to Sb Ch2. Phase 2 of evolution to Sb Ch2. Phase 3 of evolution to Sb Ch2. Drift angle Ch2. Drift Angle Ch2. Drift angle at center of gravity Ch2. Pivot point / ship stopped Ch2. Pivot Point / Speed ahead Ch2. Pivot Point / Speed Astern Ch2. Influence of Block coefficent on Pivot Point Ch2. Avoiding an obstacle at short distance Ch2. Swinging room required when turning Ch2. Heeling Angles during a turn to port Ch2. Change of trim during a turn Ch2. Reduced rudder effect with sternway Ch2. Maximum rudder efficiency Ch2. Rudder critical angle / Stalling Phenomenon Ch2. Influence of list on a turn Ch2. Influence of Block coefficient on turning characteristics Ch2. Comparison: slender and full bodied ships Ch2. Form of the ends Ch2. Effect of wind on a turn Ch2. Effect of the current on a turn Ch2. Rate of turn Indicator * With Rudder amidships and constant speed: Thrust due to the propellor and resistance of the water in the longitudinal direction are in equilibrium The vessel starts turning to starboard but is slightly drifting to port - Water resistance is shifting to port accelerating the turning moment to starboard Force Q1 opposes force Q Speed is diminishing Equilibrium between the force on the rudder and the forces exerted by the water on the portside hull forward and afterward of the center of gravity/ Pivot point: rate of turn and speed are constant. Pivot point coincides with the center of gravity With headway: the pivot point is moving forward , as a result of the water pressure at the bow Pivot point is moving astern as a result of the water pressure on the stern The pivot point of a vessel with a large block coefficient is closer to the bow: the efficiency of the rudder (steering capacity) increases Stern of Ship A too close from berth to allow for a safe turn of A to starboard Fase one Fase 2 Point of