Learning outcomes
- Follow the cargo oil path from tank bellmouths and branch lines to cargo pumps, deck mains, and manifolds.
- Explain why segregated ballast piping must not be treated as part of the cargo oil system.
- Identify the different functions of stripping, inert-gas, vent, and fire-main equipment.
Trace one service at a time
A pipe's colour or proximity is not enough to identify its duty. Begin at a known tank or item of equipment, follow the connected route, and confirm its system tag and function before naming it.
| System | Principal function | 3D location |
|---|---|---|
| Cargo oil piping | Moves cargo between cargo tanks, pumps, deck mains, and shore manifolds. | Open |
| Cargo stripping | Removes liquid remaining after the main discharge stage. | Open |
| Segregated ballast | Fills and empties dedicated ballast spaces independently of cargo oil. | Open |
| Inert-gas system | Supplies conditioned inert gas to cargo-tank vapour spaces. | Open |
| Tank vent system | Controls normal tank breathing through dedicated risers and protective devices. | Open |
| Deck fire main | Distributes fire-fighting water to deck hydrants and monitors. | Open |
How the systems differ
Cargo transfer and stripping
Cargo oil enters suction bellmouths near the tank bottom, passes through branch lines and isolation valves, and reaches the cargo mains. Cargo pumps raise pressure for discharge through deck piping and manifolds. A smaller stripping service addresses residual liquid that the main suction arrangement cannot remove efficiently.
Ballast is a segregated seawater service
Ballast pumps and mains serve wing and double-bottom ballast tanks to control draft, trim, stability, and hull loading within approved limits. The model shows ballast as a separate service, not a branch of the cargo system.
Gas control and fire protection
The inert-gas system and tank vent system both connect to cargo-tank vapour spaces, but their purposes are not identical. The inert-gas system supplies a protective atmosphere; vent risers and pressure/vacuum devices manage pressure changes. The fire main is a separate seawater fire-fighting network.
Check your understanding
Is the ballast system connected to the cargo oil system?
No. Segregated ballast piping serves dedicated ballast spaces and remains functionally separate from cargo oil piping.
What does the inert-gas system carry?
Conditioned inert gas for cargo-tank vapour spaces, not cargo oil.
Why is a stripping system needed?
It removes residual liquid near tank bottoms after the main cargo discharge arrangement can no longer drain it effectively.