#2 Seawater and ballast

Question 1

Sea Chest

Answer 1

Low sea chest: used in deep sea to prevent air from entering system when ship is rolling
High sea chest: used when ship is port or shallow waters to avoid taking in debris from seabed

Question 2

Valve

Answer 2

Regulates flow of seawater by opening, closing
Partially obstruct the passage through the pipeline

Question 3

Strainer

Answer 3

removes impurity from seawater to prevent blockages
cooler, system, pump
checked and cleaned regularly to prevent starving of water from blockages

Question 4

Seawater pumps

Answer 4

centrifugal
number of pump used depends on engine load and seawater temperature

Question 5

Cooler and condenser

Answer 5

Cooler: hot jacket water outlet from engines cooled by seawater
condenser: steam condensed back to water by seawater

Question 6

Recirculation valve

Answer 6

3 way valve used to control the temperature of cooling Seawater entering the cooler

Question 7

Emergency Bilge Suction

Answer 7

pump water out of engine room during flooding
allows large quantity of water to be pumped out of the engine room straight overboard

Question 8

Ballast System

Answer 8

pump in/ out sea water to/from shipboard tanks in large quantity and faster rate

to alter draft, list, trim

vessel trim to be leveled for steeringand propulsion

Question 9

list and trim can change during

Answer 9

cargo loading and discharging as the vessel centre of gravity will shift

ship fuel used in sailing will cause ship to be lighter, float higher and unstable

Question 10

When to ballast
Discharging cargo:
Loading:
Control list:
Control Trim:

Answer 10

Discharging cargo: ballast to make ship bottom heavy
Loading: deballast the ship to carry maximum cargo
Control list: Transfer the ballast water from port to starboard or vice versa
Control Trim: Transfer ballast from forward to aft tanks or vice versa