Freshwater System Flashcards
State the 3 main sources/top up points of F/W on the ship.
Vacuum Distillation Plant, R/O Plant, Wharf/Shore Supply
State the components of the freshwater system, their qty, & their locations on LST (6 total)
- 4x F/W Tanks, between FWD E/R and Mess 7
- 4x F/W p/ps. 2x per ER (1 pump is main, 1 pump is backup or support)
- 2x Hydrophore tanks, 1x per E/R
- 4x F/W filters, 2x per E/R (For redundancy)
- 2x UV Sterilisers, 1x per E/R
- 2x Hot Water Calorifiers, 1 per E/R
State the individual capacity of F/W Tanks 1 to 4 and thus their total volume capacity.
1 & 2: 71.5 Tonnes
3 & 4: 134 Tonnes
Total capacity: 411T
State the capacity of a F/W pump. State which F/W Pumps are pairs and must maintain Master/Slave roles. State the cut in & out of the Master & Slave pumps
15m3/h
1+2, 3+4 are pairs, e.g if F/W pump 1 is Master, F/W pump 2 must be Slave
Master p/p: Cut in (<3 bar), Cut out (=5 bar)
Slave p/p: Cut in (<2 bar), Cut out (=4 bar)
State the capacity, working pressure, safety relief pressure, and ideal water to air ratio of the hydrophore tank.
Capacity: 1000ℓ
Working Pressure: 5 bar
Safety Relief Pressure: 6.25 bar
Ideal Water to Air ratio: 7:3
State where the water to air ratio can be checked. State how to top up air or water, & what conditions need to be fulfilled.
Check the water to air ratio from the hydrophore tank sight glass
Top up water: F/W p/ps can be started on either MANUAL or AUTO
Top up air: Open the air valve to the hydrophore
While topping up, constantly look at both the sight glass (¾ or 7:3 ratio) and the pressure gauge (5 Bar) on the Hydrophore. Both conditions must be fulfilled
State the capacity & working pressure of the H/W calorifier
State the capacity of the H/W circulation pump
Capacity: 1000ℓ
Working Pressure: 7.5 bar
H/W Circulation p/p Capacity: 8m^3/h
State the capacity and working pressure of the UV Sterilizer.
Out of 3 lamps, how many lamps must be lit for the UV sterilizer to be defective?
Capacity: 15m^3
Working Pressure: 10 bar
less than 2 lamps lit = defective
State the coverage of the FWD & AFT UV sterilizer & Hot Water Calorifier.
FWD E/R
UV Sterilizer: STBD accommodation + Galley
Hot Water Calorifier: 2nd deck & above
AFT E/R
UV Sterilizer: PORT accommodation
Hot Water Calorifier: 3rd deck & below
State the 10-step process to F/W Bunkering/Topping up F/W from Wharf.
Monitoring
1. Go to the SCMMS to check sounding of the 4 F/W tanks.
2. Inform Chief MS of current water status and quantity to top up.
Preparation
3. Open the inlet valves of the F/W tanks that need to be filled.
4. Open FWD side door nearer to the top-up valve.
5. Station one operator at the wharf to receive the filling hose via side door.
Flushing
6. Connect the filling hose to the wharf top-up valve. Ship-side operator should hold on to the other end of the hose. Open Wharf top-up valve and flush hose with F/W to remove salt and particles. Close valve once done.
Top-up
7. Connect ship side hose end to the side door filling valve and open valve.
8. Open wharf top-up valve
Post Operation
9. Monitor water level of F/W tanks via SCMMS and close the F/W tank filling valves and top-up valve once done.
10. Drain hose of water before storing it.
State the 4-step process for shutting down and resetting the F/W system.
- Switch off hot water circulation pump and calorifier.
- Turn “Auto/Manual” selector switch to “Manual“, then stop the F/W p/p
- Close the water inlet v/v to the hydrophore tank
- Close the compressed air inlet v/v to the hydrophore tank
State the location of the RAS (Refuelling at Sea) valve.
Aft E/R near hydrophore tank
State the purpose/function of the FW system.
- Distribution of Freshwater for crew consumption (drinking, showering, cooking)
- cooling of M/E cylinders (jacket water)
Explain the working principles of the system and the main components as follows:
- Freshwater Pump
- Hydrophore Tank
- UV Sterilizer
- Hot Water Calorifier
- Freshwater Pump Pressurise water and send to hydrophore tank
- Hydrophore Tank Acts as a manifold to ensure pressure in f/w pipes remain stable
- UV Sterilizer
Kills bacteria in water using UV light - Hot Water Calorifier
Heats up filtered hot water, provides hot water for crew
List the Freshwater pre-sea checks.
- Check hydrophore tank water level is at ¾ through sight glass
- Check that f/w p/p cuts in at 3.5 bar, cut out at 5 bar
- Check pipes for leaks during operation, rectify any defects
- Check that UV sterilisers are functional
List the pre-start checks for the Freshwater system
- Check that supply from AEP 1/2 to the respective equipment is in ‘ON’ position.
- Ensure that there are sufficient fresh water in the fresh water tank.
- Open the fresh water storage tank valve to the fresh water pump.
- Open the suction and discharge valve of the fresh water pump.
- Open inlet and outlet valves to multimedia cartridge filter.
- Ensure multimedia cartridge filter by-pass valves are closed.
- Open the inlet and outlet valve of the U.V. sterilizer. Ensure that the bypass valve is shut.
- Select the operating switch on the front panel to #1.
- Open the gate valves to the supply line for the various decks and equipment.
List the steps to perform startup for the FW system.
FW PUMPS
Auto mode - set to auto on AEP, set either FW pump 1/3 to master slave, the other pump will follow
Manual mode - set to manual on AEP, manually turn FW pumps on
HWC
FWD: Start Stop pump & Set heater to Off, Low, High via HWC control panel
AFT: Start Stop pump, Reset, cancel buzzer, & system off/on via HWC control panel
UV sterilizer - 1 to on and 0 to off on main switch
State the operating parameters for:
Freshwater Pump Inlet & Outlet Pressure
Pressure of the Hydrophore Tank
Freshwater Pump Inlet & Outlet Pressure
2 to 5 bar
Pressure of the Hydrophore Tank
5 bar
Perform shutdown for FW system in local mode
- Switch off HWC
- Switch off f/w p/p
- Close inlet and outlet v/v of f/w p/p
- Isolate compressed air supply to hydrophore tank
- Isolate freshwater tank supply to sanitary pumps
- Close supply line v/v to various decks
Explain the safety trip parameters for Freshwater Pump Low Pressure
FW p/p unable to build pressure, possibly due to:
1. leakages —> caused by overheating, didn’t screw components tightly
2. overloading —> shaft cannot turn although the motor is running
State and explain how to perform the required PMS tasks for FW system.
Daily:
Check for leaks
UV Steriliser function check - make sure minimum 2 lights are green
Weekly:
FW Hydrophore Pump & HW circulation pump function check
1. clean pump and motor for unusual noises, knocking or excessive vibration during operation
2. check pump seal for excessive leakage
3. if deficiencies found, overhaul pump immediately
Monthly:
Check for leaks at HWC
State the number of lights currently on at the AFT & FWD UV Steriliser.
State the running temperature of the HWC.
HWC: 41-43 degrees
UV sterilizer:
FWD: Lamp 1 & 3 green, Lamp 2 red
AFT: All lamps green
Identify any two hazards for the freshwater distribution system
Thus, identify any four PPE required for the system
Noise Hazards when pumps running, Risk of burning due to hot temperature of HWC.
Mufflers, Protective Gloves, Protective Clothing, Safety boots
State 4 safe working procedures for the FW system.
- do not enter FW tank if not protected against flooding and topping up. ensure signboard is displayed to indicate maintenance work in progress
- do not run the pumps or HWC dry
- ensure UV steriliser is properly grounded, prevent severe electric shock
- Ensure that pipings & connection are all free from dirt or corrosion so that FW is safe to be used
