Mechanical Theory 3 Flashcards

1
Q

what pressure does HPSW system run at

A

7 bar

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2
Q

what is the HPSW system used for

A
  • firefighting hydrants/sprays/centre feed hose reel
  • pre-wetting system
  • fitted bilge and salvage eductors
  • emergancy cooling to main propulsion gas turbines / diesel generators
  • auxiliary machinery cooling water system
  • making of fresh water
  • flushing heads
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3
Q

What is a salt ring-main

A

A ring of pipe work, running around 2 deck, that can be sun-divided by the use of isolation

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4
Q

Where can a salt water pump be operated from

A

Local - position is close to the pump
Remote - position allows for pump to be controlled from the scc

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5
Q

What does the salt water pump do

A

Takes suction from the sea, through strainers and discharges it into the ring main via a riser

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6
Q

What is a riser

A

A vertical pipe that rises salt water from machinery space level up 2/5

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7
Q

what happens if machinery is not cooled correctly

A

temperature will continue to rise until a point where machinery fails,
either seizing, wiping its bearings or catching fire.

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8
Q

what is the melting point of white metal

A

115’c

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9
Q

what machinery is cooled by the main cooling system

A
  • Gas Turbine Cooling
  • Plummer block emergency cooling
  • Main Forced Lub system cooling
  • Controllable Pitch Propeller (CPP) cooling – if fitted
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10
Q

what is the machinery cooled by the Auxiliary circ system

A
  • diesel generators
  • ACP -air conditioning plant
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11
Q

when is oil or oily mixtures allowed to be discharged

A
  • The ship is underway.
  • The oil content (without dilution) does not exceed 15ppm.
  • The oily mixture is processed through approved oil filtering equipment.
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12
Q

what are the common sources of oily water contamination

A
  • bilges
  • fuel systems
  • oil systems
  • CPP (controlable pitch propeller)
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13
Q

give examples of specialist areas that are protected

A
  • Baltic Sea
  • North West European waters (this includes: North Sea, Irish Sea, Celtic Sea, English Channel, part of North East Atlantic)
  • Mediterranean Sea
  • Black Sea
  • Gulf
  • Gulf of Aden
  • Caribbean
  • Oman area of the Arabian Sea
  • Southern African waters
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14
Q

how do you ensure the least amount of oil enters the bilge

A
  • Keep machinery spotless, it is easier to spot leaks
  • Monitor Lub Oil ready use tanks and investigate any losses
  • No surfactants to be used
  • AFFF only to be used in real fire risk situations (not drills)
  • Eductors to be manned when in operation
  • Maximise the use of shoreside facilities when alongside
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15
Q

what is MARPOL

A

Maritime Pollution

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16
Q

who is to be inform of a marpol incident

A
  • Officer of the day
  • officer of the watch
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17
Q

what is black water

A
  • drainage and waste from WC’s
  • urinals
  • WC scuppers, medical compartments
  • any water mixed with this waste.
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18
Q

what is grey water

A
  • sewage from
  • bathrooms
  • galleys
  • dishwashers
  • laundries
  • sinks
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19
Q

what are the regulations on sewage discharge

A
  • Within 4 nautical miles of the coast if an IMO approved sewage treatment plant (STP) is in operation
  • 4 - 12 nautical miles – treated & disinfected by a IMO approved system
  • Over 12 nautical miles - no treatment
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20
Q

what is does VPS stand for and what is it

A

vacuum pumping system
* used to collect/pump black and grey water to shore facility

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21
Q

what is the salvage eductors

A
  • Used to remove quantities of fluid, generally oil/ fuel/ water from bilges very quickly
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22
Q

what is the bilge system

A
  • Removes excess fluid from machine spaces,
  • Separates water/oil
  • Discharges oil to sullage tanks
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23
Q

what is the sullage system

A

Retains dirty fluid waste until it can properly be discharged ashore

24
Q

what are eductors used for

A
  • used to suck water out of the bildge
  • uses bernoulli’s theory
  • HPSW Provides the motive force for an eductor.
  • requires permission from MEO
25
Q

explain the sequence to use the eductors

A
  1. get permission from the MEO
  2. Open the discharge overboard
  3. Open the motive water supplied from the HPSWM
  4. Open the bilge suction valves.
26
Q

what happens if the eductors are opened in the wrong sequence

A

If opened in the wrong order, you’re fucked, the machinery space will flood

27
Q

what are the health hazards asociated with sewage

A
  • Typhoid
  • Hepatitis
  • Gastro-Enteritis
28
Q

how many HPSW pumps are running in state 3

A

1 - can run whole ship alone
isolated valves are open

29
Q

how many HPSW pumps are running in DC state 1

A
  • all pumps
  • ringmain is isolated - minimise effect of damage
30
Q

how many HPSW pumps are running for special operations (flying ops)

A

more than 1

31
Q

what is the route for SW from the sea to the ringmain

A
  1. sucked from sea
  2. strainer (removes large particulates)
  3. riser
  4. ringmain
32
Q

what is the percentage for leak-off on relief valves

A

10%

33
Q

why is leak-off used

A

prevents over pressurisation

34
Q

where can pumps be operated from

A
  • remote (SCC)
  • locally
35
Q

where are fixed firefighting systems locaded on ship

A
  • magazines
  • paint lockers
  • inflam stores
  • funnels
36
Q

what is IMO

A

International Maritime Organisation

37
Q

what is the purpose of IMO

A

organisation promotes safe, secure, environmentally sound, efficient and sustainable shipping through cooperation.

38
Q

how can LP air be supplied if there is no LP avaliable

A

cross conntection from the HP air

38
Q

how can LP air be supplied if there is no LP avaliable

A

cross conntection from the HP air

39
Q

PPE when working with compressed air

A
  • Ear defenders
  • goggles
40
Q

why is fresh water used for circulation systems

A
  • machinery is susceptable to salt water corrosion
  • Other equipment can be affected by salt water contamination e.g. Gas Turbine, Fuel systems and electric motors
41
Q

what is used as coolant to cool the engines

A

AL39 + fresh water

42
Q

what type of system is a cooling circulation system

A

open loop

43
Q

what type of system is the cooling circulation system

A

closed loop

44
Q

give examples of special areas ( controlled by IMO)

A
  • Baltic Sea
  • North West European Waters (including; North Sea, Irish Sea, Celtic Sea, English Channel, part of the North East Atlantic)
  • Mediterranean Sea
  • Black Sea
  • Gulf
  • Gulf of Aden
  • Caribbean
45
Q

main sources of contamination

A
  • Bilges
  • Fuel Systems
  • Oil Systems
  • CPP Systems (Controllable Pitch Propeller)
46
Q

advantages of using a sewage treatment plant

A
  • To reduce number of ship side openings
  • To simplify pipe runs
  • Heads and bathrooms can be lower in ship
  • Heads and bathrooms can be used in dry dock
  • The ship can operate in anti-pollution areas
  • It is easier to close down in CBRN conditions (and heads can still be used)
47
Q

what is HPAC

A

high pressure air compression
* first stage - 4bar +10%
* second stage - 17.5bar+10%
* third stage - 68 bar+10%
* forth stage - 276bar +10%

48
Q

what is pre-wetting

A
  • way of cleaning top deck when comtaminated
  • sprays water - ships tilts to remove contaminated water
49
Q

name the two distinct areas of HP air

A
  • ims - inside machinery space
  • oms - ouside machinery space
50
Q

what are the two catagories of HP air

A
  • air operating below 275bar
  • air operating at 276bar
51
Q

what is aerobic

A
  • sewage is being digested
  • uses the oxygen airflow
  • (good)
52
Q

what is anaerobic

A
  • air supply fails
  • digestion is not taking place
  • hydrogen gas is produced
  • (bad)
53
Q

what does CHT stand for

A

collect Hold and Transfer

54
Q

what is CHT

A

automated system
sewage is collected in tanks
has a capacity of 12 days

55
Q

what are the hazards of STP

A

Dangerous chemicals - calcium hyprchlorite
raw sewage - typhoid, hepatits
dangerous gases - hydrogen sulphide

56
Q

explain the H2S monitor

A

H2S is given off during biological breakdown
it monitors the gas levels
must be turned on before entering the chamber
must be tanking in the tank before maintaenance