Anti-Heeling Systems on Ships
When the ship tilts on any of its sides i.e. port or starboard and doesn’t return back to its upright position, it is known as heeling of the vessel. Heeling is unsafe for the ship, its machinery, and people onboard. The main reasons for a ship’s heeling are strong winds, hard and speedy turns, and uneven cargo loading. Out of the three reasons, the most common cause is uneven cargo loading and unloading.
Anti-heeling System
The anti-heeling system of a ship automatically detects the heeling angle of the ship and compensates for the same. This allows vessels to have continuous loading and unloading cargo operations without stopping in between for list correction, saving considerable time at the port.
In this system, ballast tanks are internally connected to each other by means of pipelines, automatic valves, and control systems. When the ship heels to any of the sides, the heeling sensor sends a signal for the change of the ship’s angle with respect to the ship’s upright position to the master control panel. This change in the heeling angle is compensated by auto-transferring the water from the heeled side to the other side of the ship, making the vessel upright.
Level control switches are also installed in the ballast tank involved with the anti-heeling system to avoid low level or overfilling and hence over-pressurizing the tanks.
Types of Anti-Heeling System
- Pneumatic system: This system comprises an air purging arrangement and regulating valve system to force air on the top of the ballast tank. The air is forced on one tank and purged from the other, making the water rapidly flow from the pressurized to the purged tank. This transfer of water is used to upright the vessel in quick time.
- Water pump system: The pump system consists of an electrically motor-driven water pump, which can be a reversible or non-reversible pump, connected with remote-controlled valves that can direct ballast water flow between the tanks.
Advantages of Anti-Heeling System:
- Allows safer and rapid cargo loading and unloading.
- Shortens harbor time and saves port dues.
- Reduces damage to ramp, rolling cargo, and containers.
- Ensures the safety of the ship and personnel.
FAQs on Anti-Heeling Systems
| Question | Answer |
|---|---|
| What is the main purpose of an anti-heeling system? | To automatically detect and compensate for the heeling angle of the ship, ensuring it remains upright during cargo operations. |
| What are the main causes of ship heeling? | Strong winds, hard and speedy turns, and uneven cargo loading. |
| How does the pneumatic anti-heeling system work? | It uses air purging and regulating valve systems to force air on one ballast tank and purge it from another, making the water flow between the tanks to upright the vessel. |
| What role do ballast tanks play in the anti-heeling system? | Ballast tanks, connected by pipelines, automatic valves, and control systems, help in transferring water from one side of the ship to the other to correct the heeling angle. |
| What are the advantages of using an anti-heeling system? | It allows safer and rapid cargo loading and unloading, shortens harbor time, saves port dues, reduces damage to ramp, rolling cargo, and containers, and ensures the safety of the ship and personnel. |
| How does the water pump system in anti-heeling work? | It uses an electrically motor-driven water pump, connected with remote-controlled valves, to direct ballast water flow between the tanks. |
| Why is it important to prevent over-pressurizing of ballast tanks? | To avoid potential damage and ensure the safe operation of the anti-heeling system. |
| Can an anti-heeling system operate during continuous cargo operations? | Yes, it allows continuous loading and unloading of cargo without the need to stop for list correction. |
| What sensors are used in the anti-heeling system? | Heeling sensors and level control switches are used to detect the heeling angle and manage the water levels in the ballast tanks. |
| What is the benefit of a reversible pump in a water pump anti-heeling system? | A reversible pump can change the direction of water flow, providing greater flexibility in balancing the ship. |