NSTM Chapter 562, Surface Ship Steering Systems

Question 1

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

Answer 1

Astern rudder operations

Question 2

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

Answer 2

Design rudder torque is not exceeded

Question 3

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

Answer 3

Autopilot

Question 4

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

Answer 4

Command angle

Question 5

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

Answer 5

Dynamic rudder split

Question 6

Sometimes referred to as rudder lag

Answer 6

Dynamic rudder split

Question 7

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

Answer 7

Follow-up

Question 8

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

Answer 8

Follow-up

Question 9

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

Answer 9

Hydraulic power unit

Question 10

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

Answer 10

Indicator split

Question 11

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

Answer 11

Indicator split

Question 12

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

Answer 12

Nonfollow-up steering

Question 13

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

Answer 13

Ram roll

Question 14

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

Answer 14

Rudder angle

Question 15

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

Answer 15

Rudder rate

Question 16

Rudder rate is usually measured in ___

Answer 16

Degrees per second

Question 17

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

Answer 17

Static rudder split

Question 18

Different methods of operating the steering gear

Answer 18

Steering modes

Question 19

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

Answer 19

Steering station

Question 20

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

Answer 20

Diametrically opposite securing nuts or bolts

Question 21

When testing after repairs, take the following precautions

Answer 21

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

Question 22

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

Answer 22

110%

Question 23

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

Answer 23

Cadmium

Question 24

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

Answer 24

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

Question 25

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

Answer 25

Wash hands thoroughly

Question 26

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

Answer 26

Injury from slipping and to eliminate fire hazards

Question 27

The appropriate military specifications for large Navy surface ship steering systems

Answer 27

MIL-S-17803 | MIL-S-17903

Question 28

A ship is steered by the ___

Answer 28

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

Question 29

The function of the steering system is to ___

Answer 29

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

Question 30

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

Answer 30

Rudder control

Question 31

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

Answer 31

Torque

Question 32

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

Answer 32

Magnitude | Direction

Question 33

Torque varies with changes in ___ and is affected by ___

Answer 33

Rudder angle | Ship speed and sea state

Question 34

The steering system adapts to these changes in torque by ___

Answer 34

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

Question 35

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

Answer 35

Rudder torque curve

Question 36

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

Answer 36

The maximum torque value

Question 37

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

Answer 37

Direction that the torque is applied to the rudder stock

Question 38

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

Answer 38

0 | 25

Question 39

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

Answer 39

25

Question 40

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

Answer 40

Opposite the direction of rudder travel

Question 41

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

Answer 41

Of the rudder travel

Question 42

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

Answer 42

Away from center

Question 43

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

Answer 43

Loads and torque

Question 44

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

Answer 44

Maximum allowable ship speed that can be used for astern operations

Question 45

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

Answer 45

Command angle

Question 46

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

Answer 46

±1/4 degree | ±1/2 degree

Question 47

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

Answer 47

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

Question 48

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

Answer 48

Lost motion in each of the gearboxes and pivot joints | Sensitivity of the pump servo control valve

Question 49

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

Answer 49

±1/2 degree | ±1 degree

Question 50

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

Answer 50

2 degrees

Question 51

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

Answer 51

Indicator split

Question 52

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

Answer 52

Indicator split

Question 53

Indicator splits can be caused by ___

Answer 53

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

Question 54

Indicator splits should be corrected when they ___

Answer 54

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

Question 55

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

Answer 55

Overtravel

Question 56

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

Answer 56

Overshoot

Question 57

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

Answer 57

Rudder rate

Question 58

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

Answer 58

The maneuvering performance requirements of the ship

Question 59

When measuring rudder rate, measurement begins and ends at ___

Answer 59

30 degrees (or 5 degrees before hard over)

Question 60

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

Answer 60

Slows the rudder as it approaches the command angle

Question 61

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

Answer 61

5 to 10%

Question 62

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

Answer 62

Dynamic rudder split

Question 63

A maximum permissible rudder split should not be greater than ___

Answer 63

5°

Question 64

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

Answer 64

Static rudder split

Question 65

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

Answer 65

1° | 2°

Question 66

Two types of steering systems

Answer 66

Electrohydraulic systems | Electromechanical systems