Mechanical Theory 3 Flashcards
what pressure does HPSW system run at
7 bar
what is the HPSW system used for
- 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
What is a salt ring-main
A ring of pipe work, running around 2 deck, that can be sun-divided by the use of isolation
Where can a salt water pump be operated from
Local - position is close to the pump
Remote - position allows for pump to be controlled from the scc
What does the salt water pump do
Takes suction from the sea, through strainers and discharges it into the ring main via a riser
What is a riser
A vertical pipe that rises salt water from machinery space level up 2/5
what happens if machinery is not cooled correctly
temperature will continue to rise until a point where machinery fails,
either seizing, wiping its bearings or catching fire.
what is the melting point of white metal
115’c
what machinery is cooled by the main cooling system
- Gas Turbine Cooling
- Plummer block emergency cooling
- Main Forced Lub system cooling
- Controllable Pitch Propeller (CPP) cooling – if fitted
what is the machinery cooled by the Auxiliary circ system
- diesel generators
- ACP -air conditioning plant
when is oil or oily mixtures allowed to be discharged
- The ship is underway.
- The oil content (without dilution) does not exceed 15ppm.
- The oily mixture is processed through approved oil filtering equipment.
what are the common sources of oily water contamination
- bilges
- fuel systems
- oil systems
- CPP (controlable pitch propeller)
give examples of specialist areas that are protected
- 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
how do you ensure the least amount of oil enters the bilge
- 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
what is MARPOL
Maritime Pollution
who is to be inform of a marpol incident
- Officer of the day
- officer of the watch
what is black water
- drainage and waste from WC’s
- urinals
- WC scuppers, medical compartments
- any water mixed with this waste.
what is grey water
- sewage from
- bathrooms
- galleys
- dishwashers
- laundries
- sinks
what are the regulations on sewage discharge
- 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
what is does VPS stand for and what is it
vacuum pumping system
* used to collect/pump black and grey water to shore facility
what is the salvage eductors
- Used to remove quantities of fluid, generally oil/ fuel/ water from bilges very quickly
what is the bilge system
- Removes excess fluid from machine spaces,
- Separates water/oil
- Discharges oil to sullage tanks
what is the sullage system
Retains dirty fluid waste until it can properly be discharged ashore
what are eductors used for
- used to suck water out of the bildge
- uses bernoulli’s theory
- HPSW Provides the motive force for an eductor.
- requires permission from MEO
explain the sequence to use the eductors
- get permission from the MEO
- Open the discharge overboard
- Open the motive water supplied from the HPSWM
- Open the bilge suction valves.
what happens if the eductors are opened in the wrong sequence
If opened in the wrong order, you’re fucked, the machinery space will flood
what are the health hazards asociated with sewage
- Typhoid
- Hepatitis
- Gastro-Enteritis
how many HPSW pumps are running in state 3
1 - can run whole ship alone
isolated valves are open
how many HPSW pumps are running in DC state 1
- all pumps
- ringmain is isolated - minimise effect of damage
how many HPSW pumps are running for special operations (flying ops)
more than 1
what is the route for SW from the sea to the ringmain
- sucked from sea
- strainer (removes large particulates)
- riser
- ringmain
what is the percentage for leak-off on relief valves
10%
why is leak-off used
prevents over pressurisation
where can pumps be operated from
- remote (SCC)
- locally
where are fixed firefighting systems locaded on ship
- magazines
- paint lockers
- inflam stores
- funnels
what is IMO
International Maritime Organisation
what is the purpose of IMO
organisation promotes safe, secure, environmentally sound, efficient and sustainable shipping through cooperation.
how can LP air be supplied if there is no LP avaliable
cross conntection from the HP air
how can LP air be supplied if there is no LP avaliable
cross conntection from the HP air
PPE when working with compressed air
- Ear defenders
- goggles
why is fresh water used for circulation systems
- 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
what is used as coolant to cool the engines
AL39 + fresh water
what type of system is a cooling circulation system
open loop
what type of system is the cooling circulation system
closed loop
give examples of special areas ( controlled by IMO)
- 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
main sources of contamination
- Bilges
- Fuel Systems
- Oil Systems
- CPP Systems (Controllable Pitch Propeller)
advantages of using a sewage treatment plant
- 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)
what is HPAC
high pressure air compression
* first stage - 4bar +10%
* second stage - 17.5bar+10%
* third stage - 68 bar+10%
* forth stage - 276bar +10%
what is pre-wetting
- way of cleaning top deck when comtaminated
- sprays water - ships tilts to remove contaminated water
name the two distinct areas of HP air
- ims - inside machinery space
- oms - ouside machinery space
what are the two catagories of HP air
- air operating below 275bar
- air operating at 276bar
what is aerobic
- sewage is being digested
- uses the oxygen airflow
- (good)
what is anaerobic
- air supply fails
- digestion is not taking place
- hydrogen gas is produced
- (bad)
what does CHT stand for
collect Hold and Transfer
what is CHT
automated system
sewage is collected in tanks
has a capacity of 12 days
what are the hazards of STP
Dangerous chemicals - calcium hyprchlorite
raw sewage - typhoid, hepatits
dangerous gases - hydrogen sulphide
explain the H2S monitor
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
