Bilge & OWS Flashcards
What to do if a bilge is filling up at a fast rate?
- Inform duty engineer and summon help.
Why does a positive displacement pump not need priming?
A vacuum is created which creates a suction from the liquid.
How does the OWS work? (Stage 1)
Separator
1) Catch plates inside a coarse separating compartment and oil collecting chamber.
2) Oil has a lower density than water so the oil rises to the collecting compartment and rest settles down after passing the catch plates.
3) A control valve releases the oil into a sludge tank.
4) A heater may be used to ensure smooth flow and separation.
How does the OWS work? (Stage 2)
Filter
1) Filter, coalescer, collection chamber.
2) Impurities and particles separated by the filter.
3) Coalescer induces a process where oil droplets are joined to increase their size by breaking down their surface tension.
4) These large molecules rise above the mixture and removed when required.
5) This takes it to 15ppm.
A freshwater inlet is provided to clean and flush the filter.
How does the OWS work? (Stage 3)
OCM and Control Unit
1) PPM is continuously monitored and if high will give an alarm and feed data to the control unit.
2) If the control unit gets an alarm the 3-way valve will not allow the water to go overboard.
A freshwater connection is given for flushing. An alarm is sounded when this is in use and recorded in the OCM log.
What checks would you carry out on an OWS?
1) Periodic changing of absorbing material.
2) Regular cleaning of the surface of chambers.
3) Regular checking and troubleshooting of oil monitoring system.
4) Regular cleaning of flow regulating valves.
What are some important OWS requirements?
1) OCM must be certified by an authorised organisation.
2) OCM must be tamper-proof.
3) OCM must sound alarm when freshwater is used for cleaning or zeroing purposes.
4) Separator capable of achieving 15ppm.
5) Sensors and alarms must be installed where it cannot be monitored and maintained at all times.
What must be included in the ORB when discharging overboard?
1) Date
2) Code and item No.
3) Volume discharged and location taken from.
4) Capacity ROB.
5) Start time and stop time.
6) Position at start and stop.
7) Signature, Name, Rank and Date confirmed.
OWS start-up procedure?
1) Seek permission from the bridge.
2) OWS manual overboard valve should be locked with keys given to the master or CE.
3) Open the lock and valve.
4) Open all valves required for operation.
5) Sound tank levels and make a note.
6) Open air control, freshwater and line heating.
7) Fill the separator with freshwater as a cleaning and priming system.
8) Open water to the OCM and start the power supply.
9) An alarm should sound and now the OCM can be calibrated.
10) After the calibration sequence start the OWS supply pump.
11) Allow the system to fill and start separation. Monitor for pressure and leaks.
12) Continually monitor ppm value and when it drops below 15ppm the 3-way valve should open and begin overboard discharge.
13) Keep watch over the system and take regular soundings.
14) Make ORB entry when done.
What ships must carry an ORB?
Tanker of 150GT or above.
Ship of 400GT or above.
What is the difference between ORB part 1 & 2?
Part 1 deals with machinery space operations for all ships.
Part 2 deals with cargo/ballast operations on tankers.
When would you fill in an ORB?
1) Ballasting or cleaning of oil fuel tanks.
2) Discharge of dirty ballast or cleaning water from oil fuel tanks.
3) Collection and disposal of oil residue (sludge).
4) Discharge overboard or otherwise disposal of bilge water.
5) Bunkering of fuel or bulk lubricating oil.
Any accidental discharge and failure of OWS must also be recorded.
What are the main steps to an OWS?
1) Gravity – Uses density difference to separate.
2) Coalescing – Coming together to form larger droplets.
3) Polishing – Oil attracting material to attract the small droplets
4) Membrane – Porous material only allowing water to pass.
5) Coagulation/flocculation
Where would you find the actual designated tank names for entry into the ORB?
Supplement IOPP certificate.
