Steering Gear GME

1. Steering GearGME ajit / Tr Sup (Engg) 12/09/2012

2. Contents The force on the Rudder The Rudder Moment or Turning Moment of the ship Torque on Rudder Stock Rudder Types Balanced & Unbalanced Rudders Steering Gear Basics Steering Gear - Rudder Stock, Tiller 4 RAM Steering Gear Circuit 2 Ram Steering Gear Circuit Servo Controlled Axial Variable Delivery Pump 4 RAM Steering Gear Dubai Express 4 RAM Steering Gear 4 RAM Steering Gear movement video Piston Cylinder type Steering Gear Rotary Vane Steering Gear M.T. Atlantic Hope Steering Gear ajit / Tr Sup (Engg) 12/09/2012

3. Contents The force on the Rudder Magnitude of the Force F = KAV2, Where K = 570 to 610 based on rudder design A is the area of the rudder V is the speed of water flowing past the rudder, due either Ship’s speed Current Propeller wash Point of action of the force - Center of Pressure is at distance x from leading edge, where x = 0.195 + 0.305 Sin θ, where θ = Rudder angle ajit / Tr Sup (Engg) 07/08/2012

4. Contents Rudder Moment or Turning Moment ajit / Tr Sup (Engg) 07/08/2012

5. Contents Torque on Rudder Stock The torque on the rudder stock T = F Sin θ × distance “x” ajit / Tr Sup (Engg) 07/08/2012

6. Contents Balancing of Rudder ajit / Tr Sup (Engg) 07/08/2012

7. Contents Rudder (Turning) Moment and Torque on Rudder Stock F = KAV2 (K=570 to 610 based on rudder design) X = 0.195 + 0.305 Sinθ The rudder area is about 1/60 to 1/70 of ships L × Depth Aspect Ratio of Rudder = Breadth / Depth Lower aspect ratio preferred if no limitations to depth With higher aspect ratio, more distance needed ahead of rudder to achieve balance Semi balanced rudder is a compromise if balanced cannot be achieved due, 1. Limitations in depth 2. Limitations in distance between propeller and rudder leading edge ajit / Tr Sup (Engg) 07/08/2012

8. Contents Balanced & Unbalanced Rudders Angle of balance is the angle of rudder at which, there is no torque on the rudder stock. The rudder will remain at angle of balance without application of torque by steering gear. Balanced Rudder 20 – 37 % of area forward of turning axis There is an angle of balance Torque at 35 Deg is reduced Unbalanced Rudder No area forward of turning axis There is NO angle of balance Torque at 35 Deg is high Semi Balanced Rudder Less than 20 % area forward of turning axis There is NO angle of balance Torque at 35 Deg is less than unbalanced A is the vertical turning axis of rudder. Top fig is Balanced rudder Bottom fig is Un balanced rudder ajit / Tr Sup (Engg) 07/08/2012

9. Contents Rudder Types Rudder with Skeg support Spade Rudder Rudder on a Horn ajit / Tr Sup (Engg) 07/08/2012

10. Contents Steering Gear Basics Main Steering Gear Usually consists of two identical power units Auxiliary Steering Gear Need not be fitted if main has two power units Performance requirement of main steering gear 35 to 30 degrees movement of rudder in 28 secs with ship at service speed and design draught, with all power systems in operation (for cargo ships) Components of Electro Hydraulic Steering gear system 1. The Power Unit Electro Hydraulic (Fixed OR Variable Delivery Pumps) 2. The Actuator Ram & Cylinder Piston & Cylinder Rotary Vane (Component no: 3 below is not required for this type) 3. The tiller and rudder stock 4. The control system Electric / Electronic control system Electro Hydraulic control system Hydraulic control system ajit / Tr Sup (Engg) 07/08/2012

11. Contents Steering Gear - Rudder Stock, Tiller ajit / Tr Sup (Engg) 07/08/2012

12. Contents A – Directional Control v/v B – Bypass v/v C – Isolating v/v D – Relief v/v 4 RAM Steering Gear Circuit Meeting SOLAS requirement for tankers above 1,00,000 DWT ajit / Tr Sup (Engg) 07/08/2012

13. Contents A – Directional Control v/v B – Bypass v/v C – Isolating v/v D – Relief v/v 2 RAM Steering Gear Circuit ajit / Tr Sup (Engg) 07/08/2012

14. Contents Servo Controlled Axial Variable Delivery Pump ajit / Tr Sup (Engg) 12/09/2012

15. Contents 4 RAM Steering Gear ajit / Tr Sup (Engg) 07/08/2012

16. Contents X Head Type ajit / Tr Sup (Engg) 07/08/2012

17. Contents Dubai Express 4 RAM Steering Gear ajit / Tr Sup (Engg) 07/08/2012

18. Contents 4 RAM Steering Gear movement video ajit / Tr Sup (Engg) 07/08/2012

19. Contents Piston Cylinder type Steering Gear ajit / Tr Sup (Engg) 07/08/2012

20. Contents Rotary Vane Steering Gear Black – Rudder stock Dark Green – Rotor and Moving Vanes Pink – Stator and Fixed Vanes Pressure to Dark Blue line & Light Blue Spaces will cause clockwise rotation Pressure to Dark Green line & Light Green Spaces will cause anti clockwise rotation ajit / Tr Sup (Engg) 07/08/2012

21. Contents M.T. Atlantic Hope Rotary Vane Actuator Power Units & Hydraulic tank ajit / Tr Sup (Engg) 07/08/2012

22. Contents Movement Reversal by Directional Control v/v ajit / Tr Sup (Engg) 12/09/2012

23. Contents Pilot Solenoid Operated Direction Control v/v ajit / Tr Sup (Engg) 12/09/2012

24. Contents Heading ---------------------------------------------------------------------------------------------------------------------------------------------- ajit / Tr Sup (Engg) 12/09/2012