Turbines/ Reduction Gears and Propellers

Question 1

propellers are visually inspected at what periodicity?

Answer 1

semi-annualy

Question 2

what is used to clean the prairie holes on a propeller?

Answer 2

low pressure air

Question 3

what reference can be sued to find general information on main engine reduction gears?

Answer 3

NSTM 9420

Question 4

what two types of reduction gear teeth are in use today on propulsion reduction gears?

Answer 4

herring bone and helical gears

Question 5

main reduction gear pinion’s are made from what material?

Answer 5

forged steel

Question 6

the maximum allowable bearing temperature during engine operation is?

Answer 6

180 degrees F

Question 7

what device prevents rotation of the propeller during a casualty?

Answer 7

main engine locking device

Question 8

what medium is used to cool the stern tube during operation?

Answer 8

seawater

Question 9

after securing the engine, equalized cooling of the shaft is made possible by what device?

Answer 9

main engine jacking gear

Question 10

the main engine locking device should only be engaged when?

Answer 10

the ship is dead in the water and the propeller is not turning

Question 11

when approaching port or an anchorage, main engine lube oil temperature is reduced to what temperature?

Answer 11

100 degrees F

Question 12

why is the main engine lube oil temperature lowered to 100 degrees F upon reaching port or an anchorage

Answer 12

to minimize moisture buildup and rust formation on the reduction gears

Question 13

when laying up reduction gears for an extended period what is used to keep them moisture free?

Answer 13

dehumidifier

Question 14

the main reduction gear dehumidifier system must be checked at what frequency for correct operation?

Answer 14

daily

Question 15

permission to open any access to the main engine reduction gears must be obtained from whom?

Answer 15

engineering officer

Question 16

backlash of main engine reduction gears refers to what?

Answer 16

the gear play between the surfaces of the teeth in mesh measure at the pitch circle

Question 17

what increases engine backlash?

Answer 17

gear wear

Question 18

what NSTM deals with propulsion and SSTG turbines?

Answer 18

NSTM 231

Question 19

the high pressure turbine element is normally defined as what type of turbine?

Answer 19

impulse type

Question 20

the low pressure turbine element is normally defined as what type of turbine?

Answer 20

reaction type

Question 21

what connects the high pressure turbine to the low pressure turbine?

Answer 21

crossover or cross under pipe

Question 22

why are extraction valves fitted on some LP and HP turbines?

Answer 22

to increase steam cycle efficiency

Question 23

what does the term impulse turbine refer to?

Answer 23

a turbine in which the steam impinges upon the rotor blades and moves the rotor by a. direct push

Question 24

what type of steam turbine moves the rotor by the force of reaction?

Answer 24

reaction turbine

Question 25

what two main factors determine whether the rotor is moved by a direct impulse or reaction?

Answer 25

by the angle at which the steam hits the moving blades

Question 26

on an impulse turbine were does the steam lose pressure and gain velocity?

Answer 26

the nozzle

Question 27

in the moving blades of an impulse turbine, steam loses velocity, and pressure does what?

Answer 27

remains constant

Question 28

what type of turbine does not have a nozzle to direct steam, but has a set of fixed blades?

Answer 28

reaction

Question 29

what is the function of the fixed blades of a reaction turbine?

Answer 29

to direct the steam flow to the moving blades

Question 30

what is considered a stage on an impulse turbine?

Answer 30

one set of nozzles and the succeeding row or rows of moving and fixed blades

Question 31

what is a single stage impulse turbine usually called?

Answer 31

rateau

Question 32

what is the definition of a Curtis stage turbine?

Answer 32

a velocity compounded impulse turbine

Question 33

what does the term radial flow mean?

Answer 33

steam flows radially either toward or away from the axis of the rotor

Question 34

the astern turbine elements are located in what turbine?

Answer 34

the low pressure turbine

Question 35

what prevents foreign material from entering the high pressure turbine steam chest?

Answer 35

the main steam strainer

Question 36

what is the purpose of gland sealing steam?

Answer 36

prevents steam from leaking out of the main engine and air from being introduced into the engine

Question 37

turbine casing drains normally drain to what piece of equipment or system?

Answer 37

low pressure drain system or main condenser

Question 38

the main engine thrust bearing is normally what type?

Answer 38

kinsgbury pivoted segmental show type

Question 39

the kingsbury thrust bearing shoes serve what purpose?

Answer 39

the shoes are free to tilt and form the hydrodynamic wedge of oil between its babbitt face and the thrust collar

Question 40

what device is installed on main engine thrust bearings to indicate flow?

Answer 40

bullseye bubblers or as properly termed sight flow indicators

Question 41

what is the minimum allowable lube oil temperature prior to jacking the main engine over?

Answer 41

90 degrees F

Question 42

a bowed rotor is caused by what?

Answer 42

improper warmup or overheating of the rotor

Question 43

information on correcting a bowed rotor casualty can be found where?

Answer 43

engineering operation casualty control (EOCC) guide or NSTM 231

Question 44

what does the term singled up refer to when dealing with propulsion turbines?

Answer 44

singled up is used as an emergency means of getting underway when a casualty accurst to either the HP or LP turbine in which one is placed out of commission. Singled up of a turbine required the operator to disconnect one of the turbine's power driven unit

Question 45

what does the term locked train reduction gears refer to?

Answer 45

the two first reduction pinions are locked between the two first reduction gears and transmit power from the turbine equally to the two gears

Question 46

the main engine flexible coupling serves to protect the engine from?

Answer 46

longitudal and angular forces

Question 47

the propeller and shaft is supported outside the hull of the ship by?

Answer 47

strut and strut bearing

Question 48

what device is installed on the main engine to prevent the leakage of steam from the engine?

Answer 48

labyrinth seals