Exam Question
Write briefly on Rudder
(a) Its purpose (3)
(b) Name three types of rudders (5)
(c) Explain regarding the parts of the rudder system of a semi balanced type on the water side (8)
Class 4 (4th Engineer)
SC&S
📅 Jul 2022
Reference Answer
### (a) Purpose of a Rudder (3 Marks)
The primary purpose of a rudder is to provide directional control and maneuverability to a ship. It functions as a hydrofoil, and its operation is based on fundamental hydrodynamic principles:
1. **Generation of Transverse Force**: When the rudder is turned to a specific angle (helm angle) while the ship is moving, it deflects the flow of water. This is particularly effective when placed in the propeller race, which provides an accelerated flow.
2. **Pressure Differential**: The deflected flow creates a pressure difference between the two sides of the rudder blade. The side facing away from the turn experiences a lower pressure zone (due to increased velocity of water), while the side facing into the turn experiences a higher pressure zone.
The primary purpose of a rudder is to provide directional control and maneuverability to a ship. It functions as a hydrofoil, and its operation is based on fundamental hydrodynamic principles:
1. **Generation of Transverse Force**: When the rudder is turned to a specific angle (helm angle) while the ship is moving, it deflects the flow of water. This is particularly effective when placed in the propeller race, which provides an accelerated flow.
2. **Pressure Differential**: The deflected flow creates a pressure difference between the two sides of the rudder blade. The side facing away from the turn experiences a lower pressure zone (due to increased velocity of water), while the side facing into the turn experiences a higher pressure zone.
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