Auxillary Systems Flashcards
What pressure does the High Pressure Sea Water Main maintain?
7 Bar (100-120psi)
What 6 things are the HPSW system used for?
•Firefighting Hydrants/Sprays/Centre Feed Hose Reel (CFHR)
•Pre-wetting System
•Fitted Bilge and Salvage Eductors
•Emergency Cooling to Main Propulsion Gas Turbines / Diesel Generators
•Auxiliary Machinery Cooling Water System
•Making of fresh water
•Flushing heads. (not applicable to later ships e.g. Type 23 or Type 45)
What happens during DC state 1?
The ring main is isolated, state valves closed. All pumps running.
What happens during DC state 3?
One pump is running supplying the whole ship. Other pumps are on standby and can be started if the pressure drops. All the DC State valves are open.
When is the pre wet system used?
In an NBC environment to reduce Nuclear, Biological and Chemical contamination levels of the upper deck
What is a riser?
A vertical pipe that raises salt water from machinery space level up to 2/5 deck.
What is pump leak off?
Each pump has its own 10% leak-off valve to Prevent Over Pressurisation (10% above normal pressure of 7 bar)
Where would you find sprays aboard ship?
- Magazines
- Paint lockers
- Inflam store
- Funnels
What is the HPSWM supplied by?
The sea, through a strainer, pumped by electrically driven pumps up the riser.
What temperature does white metal melt?
115 Degrees
What are the effects of metal overheating?
It’ll fail, seize, wipe the bearings, or catching fire.
What equipment does the main propulsion circulating system cool?
- Gas turbine cooling
- Plumber block emergency cooling
- Main forced Lub system cooling
- Controllable Pitch Propeller cooling.
What two things are cooled by the auxiliary cooling system?
Air conditioning plant and diesel generators.
What are the 6 special places for discharging oil?
- Baltic sea
- North West European Seas
- Mediterranean Sea
- Black Sea
- Gulf
- Gulf of Aden
- Caribbean
- Oman area of the Arabian Sea
- Southern African waters
What are eductors used for?
Eductors are used to suck water out of the bilge.
What three diseases can you get from raw sewage?
- Typhoid
- Hepatitis
- Gastro-Enteritis
What are the six advantages of a sewage treatment plant?
- To reduce the 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 are the two categories of high pressure air?
- Air operating at 276 Bar
- Reduced HP air operating below 276 Bar (reduced by a reducing valve)
What are the uses for HP air?
- Diesel engine starting
- Gas turbine starting
- Ship siren operation
- Breathing apparatus
- Weapon systems operation
- Hydraulic system accumulator charging
- Air driven machinery operation
- Cross connection to Low Pressure Air System (276 bar to 8 bar)
What are the pressures for the four different stages in an air compressor?
4,17.5,68,276 Bar
What is LP air used for?
- Pneumatic tools
- Radar wave guides
- Emergency Stern Seal Inflation
- Pneumatic Surveillance Panels
What pressure is the LP air system?
8 Bar
What are the 6 hazards and precautions for working with HP/LP Air?
- High pressure air an be lethal if it enters the bloodstream, do not point it at anyone.
- Ear defenders must be worn.
- Explosion (dieseling) HP air coming into contact with oil or grease can be explosive.
- Use silicone grease to prevent dieseling.
- Flexible hoses - hoses must be “whipped” (bound and tied) to secure both ends and prevent “flailing”
- Hoses are “lifed” (dated with an expiry”
What are the alarms and warnings for a HP air compressor?
- High water temperature (switch operates at 54 degrees C)
- Low oil pressure (switch operates at 0.69 bar)
At what pressure does the water jacket safety valve stop?
3.5 Bar - protecting the FW and SW cooling systems.
What are the five safe working practices when filling air bottles?
- Bottle must be located in purpose built rack
- Operators must be wearing PPE
- Hoses must be in good condition and connected with the correct spanner.
- A good condition O seal must be used.
- Bottle should be filled slowly to avoid overheating.
What is the PPE required when charging air bottles from HP air?
- Goggles
- Ear defenders
What is the bilge?
A section of the bottom of the ship where spillage, leakages, and condensation collects much like a sump in a car engine.
Why is it important to keep bilges empty?
Build up in bilges creates a fire hazard and there is a chance that toxic gases may be present
What methods are available to empty the bilge?
Eductors in emergency with the MEOs permission as it by passes the bilge system.. The bilge system which separates oil/fuel from water and retains and retains the fuel/oil on board while discharging the water overboard. The Sullage system this can discharge to a tank or shoreside facility.
What is the bilge system?
A bilge system is fitted to remove excess fluid from machinery space bilges to separate water from oil and discharge oil to sullage tanks by means of an oily water separator, with the water being discharged overboard
What is the sullage system?
A system that retains the dirty oily/fuel waste until it can be discharged properly ashore. The discharge from the billage system is directed to the sullage tanks.
What are Eductors used for?
They are used to suck fluid out of the bilge using the Bernoulli’s theorum straight overboard.
What is the correct order to operate an Eductor?
- Open the discharge overboard valve.
- Open the motive water valve supplied by the HPSWM.
- Open the bilge suction valves.
What may happen if an eductor is operated incorrectly?
If the valves are opened in the incorrect order the bilge can flood with sea water from the HPSWM.
What must an Eductor be when in operation?
Manned and Observed.
State the machinery being cooled by the main propulsion cooling system?
- Lub oil heat exchanger
- Gas turbine heat exchanger
- CPP unit heat exchanger
- Plummer block heat exchanger
State the machinery being cooled by the auxiliary cooling system?
- Air conditioning plant
- Diesel plant/generators
When would a cross connection between port and starboard be used?
When doing maintenance on one of the strainers.
What temperature do white metal bearings melt at?
115 degrees
What may happen if machinery is not cooled correctly?
Failure, seizing, wiping of bearings and catching fire.
Why is fresh water used in a cooling system?
Some equipment is susceptible to sea water corrosion and it stops sea water contamination.
What definition of system is the FW/SW?
FW is closed loop
SW is open loop
When could the FW system be cross connected to the SW system?
In emergency, likely when there is a lack of freshwater or the temperature is too high, with permission of the MEO
What is the IMO?
The International Maritime Organisation.
What is the MARPOL?
The Maritime Pollution Regulations 1973/78
What is the requirements of a ship with regards to oil discharge when within 12nm of the coast?
- The oil content in the discharged water must not exceed 15ppm
- The ship is underway with an oil content in the effluent under 15ppm
- The ship has in operation an oily water separating filter with an oil discharging monitoring control system.
State the 6 special areas as defined by the IMO
- Baltic Sea
- Mediterranean Sea
- North West European waters; North Sea, Irish Sea, Celtic Sea, English Channel, part of the North East Atlantic.
- Black Sea
- Gulf
- Gulf of Aden.
- Caribbean
What are the four main sources of contamination?
- Bilges
- Fuel systems
- Oil systems
- CPP Systems
If a MARPOL incident occurs who is informed?
The MEOOW
The MEOOTD
How can oil leakages in the bilge be minimised?
- Keep machinery spotless - easier to identify leaks.
- Monitor Lube Oil ready to use tanks and investigate any losses.
- No surfactants to be used.
- AFFF only in real fire risk situations
- Eductors to be manned when in operations
- Maximise the use of shoreside facilities when alongside
What is Black water?
- WC’s
- Urinals
- WC Scuppers
- Medical components
- Any water mixed with this waster
What is grey water?
- Bathrooms
- Galleys
- Dishwasher
- Laundries
- Sinks
What is the regulations with regards to Black Water discharge at:
- 0-4nm = Within 4nm discharge is only permitted with an IMO approved sewage treatment plant (STP)
- 4-12nm = Between 4-12nm discharge is only permitted if an IMO approved system to Comminute and disinfect the sewage is in operation.
- 12nm+ from shore no treatment is necessary
What is the VPS and what will it consist of?
The Vacuum Pumping System comprises of a “fitted for ship” set of diesel or electric driven pumps, manifolds and hoses which pump all black and grey water discharges to shoreside facilities.
Why is high pressure air used onboard?
Where is high pressure air used on board?
- Inside machinery spaces (IMS)
- Outside machinery spaces (OMS)
State six services that use high pressure air:
- Diesel engine starting
- Gas turbine starting
- Ship siren operation.
- Breathing apparatus (BA) charging
- Weapon systems operation.
- Hydraulic system accumulator charging.
- Air driven machinery operation.
- Cross connection to Low Pressure Air System (276 bar to 8 bar)
When will relief valves operate?
When pressure exceeds 10% of what it should be.
What are the four stages of air pressure for High Pressure Air Compressors?
Stage 1 - 4 bar
Stage 2 - 17.5 bar
Stage 3 - 68 bar
Stage 4 - 276 bar
What is the purpose of the HPAC drain and separators and how often do they operate?
Remove condensation from the air and drain water from the compressor, and operates every 30 mins of running time.
What pressure will the water jacket safety valve operate and what system is it protecting?
3.5 bar and protects the FW cooling system and the SW main.
What are the two alarms on the High Pressure air compressor?
- High water temperature (54 degrees)
- Low oil pressure (0.69 bar)
What is the LP air operating pressure?
Up to 7 bar
State four services that use the LP air:
- Pneumatic hand tools
- Radar wave guides
- Emergency Stern Seal
- Pneumatic Surveillance Panels.
What PPE is required when charging air bottles?
- Goggles
- Ear defenders
What is the HPSW operating pressure?
7 bar approx (100-120psi)
What is fitted to prevent system over pressurisation?
10% leak off valve and pressure relief valve.
State 6 uses of HPSW:
- Firefighting.
- Pre-wet
- Fitted bilge and salvage Eductors
- Emergency cooling to main propulsion gas turbines, diesel generators.
- Auxiliary Machinery cooling water system.
- Making of fresh water.
- Flushing heads.
Explain the flow of SW from the sea to the ring main:
Sea cock - Strainer - Electrically driven pumps - Riser - Ringmain
How are the HPSW pumps driven?
Electrically, and they can be operated from a local position or from the SCC.
Where will the HPSW sprays be located?
- Inflam stores
- paint lockers
- Magazines
- Funnels
Explain the pre wet system:
The pre wet system is used in an NBC environment to reduce contamination levels of the upper deck and can be sprayed over the ship to prevent toxins from sticking and to wash them off.
What are the advantages of having an STP on board?
- Reduces the number of ship side openings
- Simplifies 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 be still be used)
What is aerobic digestion?
The act of bacteria digesting sewage using air.
What is anaerobic digestion?
Digestion of sewage without the presence of air.
How would you detect Anaerobic digestion at low levels?
Hydrogen sulphide will begin to be produced creating a smell of rotten eggs.
What could cause anaerobic digestion?
The air supply failing due to blockage.
What is the purpose of the coarse screen?
To remove large particles before the filter
What is the purpose of the aeration diffuser?
To pass oxygen through the waste, preventing anaerobic digestion.
What is the effect of H2S at:
- 0.03ppm = detectable by odour
- 20-30ppm = odour becomes sweetish
- above 30ppm = odour fades due to fatigue
- 70-150ppm = Kills sense of smell in 3-15mins, irritates eyes, throat and lungs.
- 700-1000ppm = Immediate threat to life is unconsciousness and permanent brain damage.
- 1000ppm+ = Immediate unconsciousness and death within seconds.
What hazards are associated with raw sewage?
- Typhoid
- Hepatitis
- Gastro - Enteritis.
What hazards are associated with STP’s?
- Dangerous Chemicals
- Raw sewage
- Dangerous gases (hydrogen sulphide and methane)
Why do we use high pressure air on board?
- Easily distributed about the ship
- Easily stored
- Flexibility and reliability of use
- Low fire risk