Questions for exam

Question 1

Explain the 4 cycles of a refrigerator:

Answer 1

1. Compressor: The compressor serves to increase the refrigerant pressure which is still in a gas state. It is then pumped to the condenser via the discharge line
2. The condenser serves to extract heat from the refrigerant, changing it to a liquid state. The refrigerant is still at a high pressure.
3. Expansion valve/TX valve serves to rapidly decrease the pressure and temperature of the refrigerant.
4. In the evaporator the refrigerant will start to boil, which will pull heat from the surrounding air, which provides the cooling effect.

Question 2

5 common faults of a refrigerator:

Answer 2

1. Undercharge. 2. Overcharge 3. Water in system. 4. Iced expansion valve 5. Compressor failure

Question 3

What type of garbage cannot be discharged overboard?

Answer 3

Plastic

Question 4

5 pollutes annex 6:

Answer 4

1. HALONS
2. CFCs
3. NOx
4. SOx
5. PCBs

Question 5

Which vessels require an oil separator?

Answer 5

Vessels over 400 gross tonnage

Question 6

Types of garbage annex 5:

Answer 6

1. Cooking oil
2. Cargo residues
3. Domestic waste
4. Incinerator ashes
5. Operational wastes

Question 7

How often must a water tank be inspected and cleaned?

Answer 7

12 months. In addition tanks should be thoroughly pumped out and, where necessary, hosed prior to refilling at approximately 6 month intervals.

Question 8

3 oil record book categories of entry:

Answer 8

1. Ballasting or cleaning of oil tanks
2. Accidental discharge of oil
3. General remarks

Question 9

Why is breakdown maintenance considered unacceptable?

Answer 9

Breakdown maintenance will result in unnecessary excessive cost to the owner, injury, damage or pollution.

Question 10

What is meant by CBM?

Answer 10

CBM stand for Condition Based Maintenance. CBM is a maintenance strategy which utilizes real-time data to determine the condition of machinery and equipment with the aim to predict when maintenance is required or to prevent failures.

Question 11

5 advantages of CBM

Answer 11

1. Cost savings
2. Increased uptime
3. Increased equipment life
4. Improved safety
5. Less manpower

Question 12

Definition of an enclosed space:

Answer 12

A space with inadequate ventilation and where harmful gases may be trapped.

Question 13

5 sections of a permit to work:

Answer 13

Mnomonic: Super Cute Cat Plays Energetically

1. Scope of work
2. Checklists
3. Certificate of checks
4. Personnel Entry
5. Cancellation of certificate

Question 14

Sketch a 3 stage sewage system:

Answer 14

Start with the primary chamber:

1. primary chamber receives black water through a screen. It moves down, past a wall, and then up and to left of the sketch into the Aeration chamber.
2. Inside the aeration chamber the sewage receives oxygen provided by a pump. It will then flow to the settlement tank.
3. Settlement tank: The settlement tank allows heavy solids to sink to the bottom, where it will be pumped back to the aeration tank. After the settlement tank, it will flow to the chlorination tank.
4. Chlorination tank: Here the effluent is treated.

Question 15

How often should a fresh water tank be cleaned

Answer 15

every 12 month and when it is opened.

Question 16

Hydraulic symbols:

1. Circle with a triangle at each side
2. Circle with only one triangle
3. Circle with a triangle at each side but with an arrow

Answer 16

1. Bi-directional actuator
2. Constant pressure pump
3. Variable delivery pump

Question 17

most common electrical system on a small vessel:

Answer 17

3 phase 380v

Question 18

Insulation:

Answer 18

Minimum values of 1mega Ohm is acceptable. But minimum values of 50 mega ohm is normal for a clean dry motor in good condition

Question 19

Observations for an oil sample:

Answer 19

1. Colour
2. Odor
3. Viscosity
4. Contaminants
5. Water content

Question 20

Why might the atmosphere be dangerous in an enclosed space:

Answer 20

Lack of oxygen
Toxic gases
Flammable gases