Rudders, Propulsion & Tugs Flashcards
How does a rudder work?
deflects water flow to generate a directional force.
What are the different types of conventional rudders?
Balanced.
Semi Balanced.
Spade.
(These rudders allow angles up to 45degrees)
What are the different types of high lift rudders?
Becker.
Schilling.
Fishtail.
(Fitted normally on small/ medium size vessels, this rudder allows for a much greater degree of control).
What factors influence rudder response?
Ships speed.
Rudder dimensions.
Rudder angle.
UKC.
The vessel’s trim.
What are the two types of propellers?
- Fixed Pitch Propellers (FPP).
- Controllable Pitch Propellers (CPP).
What are the two types of drivetrain associated with FPP?
- Direct drive.
- Indirect Drive.
What is a direct drive FPP?
- This is the cheapest type of engine.
- Limited to the number of engine starts (12 time minimum)
- It is required to be stopped when changing from ahead to astern.
- The propeller turns to the right, when going astern it goes anticlockwise
- When the controls are at zero, the engine is stopped, and the propellers do not turn
What is a indirect drive FPP?
- No limit to the number of starts.
- Engine constantly running, does not have to be stopped when changing from ahead to astern.
- When controls at zero, the engines do not stop but disengage the clutch.
- Propeller slows doesn’t stop and turns clockwise when going ahead.
What are Controllable Pitch Propellers?
- In Vessels with CPP the engine runs constantly.
- Propellers will always spin even at zero pitch.
- Propellers can turn to either right or left.
- Highly manoeuvrable but they are not always guaranteed to go to port or starboard.
What are tugs used for?
- Tugs are used to assist with manoeuvring were needed due to any conditions that may make it difficult for the vessel to manoeuvre alone.
What accommodations should be made by the vessel when using tugs?
- Vessels should be adjusted as necessary when working alongside tugs and extra care must be taken.
- Extreme care must be taken when handling tug lines or tug lines being fast in mooring stations.
