Tanker Familiarization Tanker Systems and Equipment Questions and Answers 1

Question 1

What is the primary safety function of the deck water seal in a tanker's inert gas (IG) system?

Accepted Answer

To act as a non-return device, preventing flammable cargo vapours from flowing back to the machinery space.

Answer

The deck water seal is a critical safety barrier that allows inert gas to flow from the IG plant to the cargo tanks but uses a column of water to physically block any reverse flow of hydrocarbon gases from the tanks back towards the engine room, where ignition sources are present.

Question 2

During the final stages of discharging a cargo tank, the main centrifugal cargo pump begins to lose suction and cavitate. Which system is specifically designed to efficiently remove the final quantities of cargo from the tank?

Accepted Answer

The stripping system.

Answer

Centrifugal pumps are high-capacity but are not efficient at pumping when the suction level is very low or when pumping a mix of liquid and vapor. Stripping systems, which often use positive displacement pumps or eductors, are specifically designed to remove the final quantities of cargo ('the strip') from the bottom of the tank.

Question 3

Which of the following is the primary purpose of a Pressure/Vacuum (P/V) valve fitted on the vent line of a cargo tank?

Accepted Answer

To automatically relieve minor over-pressure or under-pressure, preventing structural damage to the tank.

Answer

P/V valves are automatic safety devices that protect the tank from damage caused by small pressure fluctuations due to temperature changes or cargo movement. They open to release pressure when it exceeds a set point and open to admit air/gas when a vacuum develops, thus maintaining the tank's structural integrity under normal operating conditions.

Question 4

In a Crude Oil Washing (COW) system, what is used as the washing medium to clean the cargo tanks?

Accepted Answer

The cargo of crude oil itself.

Answer

Crude Oil Washing (COW) is a process where the crude oil cargo being discharged is itself used as the cleaning fluid. It is directed through fixed tank cleaning machines to dissolve and wash away waxy residues and sludge from the tank surfaces, which improves the cargo outturn.

Question 5

A tanker is loading cargo. An audible and visual alarm activates, indicating the tank level has reached 98% capacity. According to SOLAS requirements, this alarm must be triggered by a system that is what?

Accepted Answer

Independent of the primary tank level gauging system.

Answer

To prevent cargo spills, regulations (like SOLAS and the IBC code) require at least two independent systems for level monitoring. The primary gauging system provides continuous readings. A separate, independent system provides a high-level alarm (at ~95%) and a high-high or overfill alarm (at ~98%), which serves as a final safety barrier.

Tanker Familiarization Practice Test

Tanker Familiarization Practice Test

Tanker Familiarization Tanker Systems and Equipment Questions and Answers 1