Every year, billions of dollars’ worth of bulk cargo is loaded onto ships and transported worldwide. This includes valuable materials like silver, lead, zinc, copper, and essential energy resources. However, this cargo is often weighed using methods like the traditional draught survey, which can lead to significant inaccuracies. These errors can cost companies millions of dollars.
Control Systems Technology (CST) offers a way to avoid this costly problem.
The limitations of draught surveys
Draught surveys have been used for centuries to measure bulk cargo by calculating changes in a ship’s displacement in water. While widely accepted, this method is not exact. In fact, it can have a margin of error up to +/- 0.5 per cent, and many factors can make it even more inaccurate.
For example, weather conditions, worn-out markings on the ship, or even human error when reading measurements can all contribute to mistakes. A small misreading can result in thousands of tons of cargo being incorrectly measured, leading to costly miscalculations.
Common issues with draught surveys:
- Difficulty reading the draught marks on a ship, especially in poor weather or darkness.
- Inaccurate water density readings, which affect the calculations.
- Human error when measuring the ballast (water used to balance the ship).
- Extra weight from mud, silt, or unaccounted water in the ship’s tanks.
- Structural changes to the ship over time, affecting the data.
With all these factors in play, it’s easy to see how errors can multiply, resulting in significant inaccuracies.
A smarter solution: Belt scales
Instead of relying on outdated methods, a conveyor belt weigher (also known as a belt scale) can eliminate these risks. This system measures the weight of cargo as it’s loaded onto the ship, avoiding the need to rely on water-based measurements entirely.
CST has been developing highly accurate belt scales for years. For example, at the Callao Port in Peru, CST installed a conveyor belt weigher that consistently operates with an accuracy of +/- 0.1 per cent, much better than the +/- 0.5 per cent of draught surveys. This system has been running without adjustment for 18 months and is critical for loading copper concentrates onto ships.
Why choose CST’s belt scales?
- They provide operations with a much more accurate reading than traditional methods.
- The system is custom-designed for specific conditions, ensuring durability and reliability in any environment.
- CST’s scales have been proven to provide better weighing solutions for ports all over the world, including key installations in Australia.
Contact CST today to learn how it can help operations run better than ever.
