NSTM Chapter 562, Surface Ship Steering Systems Flashcards Preview

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Flashcards in NSTM Chapter 562, Surface Ship Steering Systems Deck (66)
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1
Q

The use of the steering gear while the ship is moving in the reverse direction

A

Astern rudder operations

2
Q

On some ships, the astern speed, maximum rudder angle, or both are limited during astern operations so that the ___

A

Design rudder torque is not exceeded

3
Q

Steering control equipment that allows the helmsman to enter a heading order for the ship, the ship maintains the heading without the need for steering with a helm wheel

A

Autopilot

4
Q

The ordered or desired rudder angle that is input by the helmsman at the helm or differential control unit through manual operation of a helm wheel

A

Command angle

5
Q

A condition where one rudder takes longer than a second rudder when the system is responding to a change in the command angle

A

Dynamic rudder split

6
Q

Sometimes referred to as rudder lag

A

Dynamic rudder split

7
Q

Components within the steering system that follow the position of the hydraulic rams or rubber stock and send a mechanical or electrical signal to the controls that is in proportion to the actual rudder position

A

Follow-up

8
Q

The ___ provides a rudder position feedback signal to the control and nulls the pump output as the command angle is reached

A

Follow-up

9
Q

Components of a hydraulic system that include the pump, electric motor, and other components needed to control the rudder

A

Hydraulic power unit

10
Q

A condition where the helm angle indicator and rudder angle indicators do not display the same angle even though the rudder is not moving

A

Indicator split

11
Q

An ___ can also occur when the rudder angle indicators do not display the same angle as the mechanical rudder angle indicator located near the rudder stock

A

Indicator split

12
Q

A steering mode available on some ships that uses a type of joy-stick control to turn the rudder to the left or right. In this mode, the steering system does not position the rudder to an ordered angle

A

Nonfollow-up steering

13
Q

A condition where the ram rotates slightly about its longitudinal axis as the rudder moves

A

Ram roll

14
Q

The actual position of the rudder, measured in degrees from the zero position

A

Rudder angle

15
Q

The average speed the rudder moves during a hard-over to hard-over rudder swing while moving ahead at the maximum rated ship speed

A

Rudder rate

16
Q

Rudder rate is usually measured in ___

A

Degrees per second

17
Q

A condition where the rudders of a ship do not stop at the same exact angle

A

Static rudder split

18
Q

Different methods of operating the steering gear

A

Steering modes

19
Q

The locations on the ship, usually the bridge and steering gear rooms, where the steering equipment can be controlled

A

Steering station

20
Q

In breaking flanged joints, ensure that two ___ remain tight while the remainder are slacked

A

Diametrically opposite securing nuts or bolts

21
Q

When testing after repairs, take the following precautions

A

Use a small-volume external pressure source for hydrostatic tests
Protect reassembled joints with spray shields or by wrapping them with polyethylene bags

22
Q

Before use, subject temporary hoses to a shop hydrostatic pressure of at least ___ of the maximum pressure that the hose will be subjected during the temporary use on the ship

A

110%

23
Q

Do not use ___ plated parts in any hydraulic unit where they may come in contact with hydraulic oil

A

Cadmium

24
Q

Why shouldn’t cadmium-plated parts be used in a hydraulic unit where they may come in contact with hydraulic oil?

A

Cadmium reacts chemically with hydraulic fluid with detrimental results to system operation

25
Q

___ after working with cadmium-plated tools or parts to avoid poisoning from ingestion of cadmium-contaminated food

A

Wash hands thoroughly

26
Q

Remove oil spills or leaks as soon as possible to prevent ___

A

Injury from slipping and to eliminate fire hazards

27
Q

The appropriate military specifications for large Navy surface ship steering systems

A

MIL-S-17803

MIL-S-17903

28
Q

A ship is steered by the ___

A

Force of the water acting on the rudder as the ship moves through the water

29
Q

The function of the steering system is to ___

A

Control the position of the rudder against the force of the water

30
Q

Involves turning the rudder to a desired angle in degrees and holding the rudder in position

A

Rudder control

31
Q

The force from the water on the rudder creates a ___ on the rudder stick

A

Torque

32
Q

The ___ and the ___ or torque acting on the rudder stock are not constant

A

Magnitude

Direction

33
Q

Torque varies with changes in ___ and is affected by ___

A

Rudder angle

Ship speed and sea state

34
Q

The steering system adapts to these changes in torque by ___

A

Producing enough countering torque on the rudder stock to control the position of the rudder

35
Q

Shows the estimated rudder torque at the maximum ship speed for a particular ship

A

Rudder torque curve

36
Q

The basis for determining the sizes of the rudder actuator and the steering gear power units

A

The maximum torque value

37
Q

The negative and positive regions of the rudder torque curves graph indicate the ___

A

Direction that the torque is applied to the rudder stock

38
Q

For most ships, the rudder torque direction changes at the ___ rudder angle and at a ___ rudder angle

A

0

25

39
Q

The rudder has a natural tendency to travel to the ___ degree position left or right of center

A

25

40
Q

When the rudder torque is negative, the steering gear applies torque in the direction ___

A

Opposite the direction of rudder travel

41
Q

When the rudder torque is positive, the steering gear applies torque in the direction ___

A

Of the rudder travel

42
Q

When the ship is moving in reverse, the force of the water on the rudder tries to move the rudder ___

A

Away from center

43
Q

The design and shape of the rudder affect the ___ acting on the rudder and steering system

A

Loads and torque

44
Q

Instead of adding excess weight to the steering system strictly for astern operations, the ____ is limited

A

Maximum allowable ship speed that can be used for astern operations

45
Q

When operating properly, the steering system will position the rudders to the ___

A

Command angle

46
Q

Steering systems with new or overhauled follow-up assemblies are required to have a mechanical comparative error of not more than ___ from 0 to 5 degrees rudder angle and ____ for any rudder angle greater than 5 degrees

A

±1/4 degree

±1/2 degree

47
Q

The comparative error requirement is based on measurements taken at the ___ and the ___

A

Rudder angle indicator on the mechanical differential steering stand
Mechanical rudder angle indicator on the tiller or rudder actuator

48
Q

Accuracy of the steering is affected by ___ and by the ___

A

Lost motion in each of the gearboxes and pivot joints

Sensitivity of the pump servo control valve

49
Q

Realistic accuracy requirements are a comparative error of not more than ___ from 0 to 5 degrees of rudder angle and ___ for any rudder angle greater than 5 degrees

A

±1/2 degree

±1 degree

50
Q

An error of up to ___ is allowed when comparing the rudder angle indicated on the ship control console, or other remote electrically-operated indicators, with the mechanical rudder angle indicator in the steering gear room

A

2 degrees

51
Q

A condition where the helm angle indicators and the rudder angle indicators do not display the same angle even though the rudder is not moving

A

Indicator split

52
Q

Occurs when the rudder angle indicators do not display the same angle as the mechanical rudder angle indicator located near the rudder stock

A

Indicator split

53
Q

Indicator splits can be caused by ___

A

Lost motion or misalignment of the follow-up mechanism or by problems with indicator calibration

54
Q

Indicator splits should be corrected when they ___

A

Exceed the rudder position accuracy or remote rudder angle indicator accuracy requirements

55
Q

Condition where the steering system positions the rudder beyond the command angle and the rudder remains in that position

A

Overtravel

56
Q

Condition where the steering system turns the rudder beyond the command angle then reverses direction to position the rudder where it should have stopped

A

Overshoot

57
Q

The average speed that the steering system rotates the rudder under full power and full pump output conditions

A

Rudder rate

58
Q

Rudder rate is a design criteria for the steering system that is based on ___

A

The maneuvering performance requirements of the ship

59
Q

When measuring rudder rate, measurement begins and ends at ___

A

30 degrees (or 5 degrees before hard over)

60
Q

The final five degrees are not used to determine rudder rate because the steering system ___

A

Slows the rudder as it approaches the command angle

61
Q

Measured rudder rates are approximately ____ faster when measured at the pier rather than underway

A

5 to 10%

62
Q

Condition where one rudder takes longer than, or lags behind, a second rudder when the system responds to a change in the command angle

A

Dynamic rudder split

63
Q

A maximum permissible rudder split should not be greater than ___

A

64
Q

Condition where the rudders of a ship do not stop at the same exact angle

A

Static rudder split

65
Q

When the rudders are not moving, the difference between the two angles should not exceed ___ for rudder angles between 0 and 5 degrees, and should not exceed ___ for any rudder angles greater than 5 degrees

A

66
Q

Two types of steering systems

A

Electrohydraulic systems

Electromechanical systems