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
