ADCP's Application to Ocean Current Measurement in Port of Durban

1. Where is the Port of Durban

The Port of Durban is on the east coast of South Africa. It is one of the biggest and busiest ports in Africa and, importantly, a key factor in maritime trade into and around the continent.

Port Scale and Throughput

• Scale: It is large in size and has various berths. It has an adaptive capacity to tackle the huge dimensions of the modern giant-sized container vessels, bulk carriers, and oil tankers. It is designed for appropriately regulating the oncoming movement and goods within the harbor.
• Throughput: This port boasts of high output for a wide variety of cargo. It is the major South African export gateway, whose common freight includes minerals, agricultural produces such as grains, fruits, and sugar, and manufactured goods. These ports also import lots of machinery, consumer goods, and raw materials. It experiences volumes of cargo annually that are considerable enough to make it one of the leading performer shipping ports in the world.

Routes and Business

• Route: The Port of Durban is well-integrated into the globe. It boasts of several important shipping lines connecting it to Europe, Asia, and the Middle East, among other African ports. These routes form the umbilical cord of international trade and play a crucial role in the economic development of South Africa and the surrounding region.
• Business: The major business activities are container handling, which is a growing sector considering the present scenario of increasing globalization of trade. It also handles a considerable bulk cargo like coal and ores. Besides, vehicle import and export, chemicals, and other general cargo services are provided at the port.

Port Management and Operation

• The port is managed by an efficient team that seeks to ensure very smooth and safe operations. Advanced technologies are being used in the handling of ship traffic, cargo handling, and storage management.
• Stringent safety and environmental regulations have been put in place at the port with the aim of reducing risks towards the protection of the surrounding ecosystem. Regular training programs help the port personnel to keep the standard of operation intact.

Port Facilities and Waterway

• Infrastructure: The port has several deep-water berths, endowed very well with modern cranes and appliances for the operation of loading/unloading. There is extensive storage space comprising container yards, general cargo warehouses, and silos for bulk commodities like grain. Besides, there are ship repair facilities within the port.
• Waterway: The waterway to the port is well looked after. It is dredged from time to time in order to accommodate big vessels. A well-equipped pilotage service guides the ships into the port safely. Buoys and lights that assist the ships are provided during entry and exit.

2. Why measure ocean currents in the Port of Durban?

Navigation Safety

The measurement of ocean currents is very important for navigation safety in the Port of Durban. The port is a busy place, with a high volume of traffic, ranging from large container ships and bulk carriers to oil tankers, all of which may be heavily affected by ocean currents. For example, a strong cross-current at the entrance of the port can make a ship deviate from its course and increase the danger of collision with other vessels, piers, or running aground. With proper measurement of current speed and direction, captains are able to plan their approach and departure better by making appropriate adjustments to course and speed for safe passage.

Optimization of Port Operations

Knowledge helpful in the optimization of port operations may include ocean currents, for example. In the case of approaching the berthing/unberthing process, current flow may be different in time and efficiency. A correctly oriented current direction might thus support the docking phase in any particular instance without demanding extensive tugboat interventions to counteract the effect produced, thus saving money and time. The knowledge about current will also assist in effectively planning the scheduling process in loading and unloading cargo by understanding current patterns. It also can be useful in handling liquid cargo, such as oil, because knowledge of currents would avoid spillage and ensure operational safety.

Infrastructure Planning and Maintenance

The measurement of the current would also be necessary for the long-term planning of the port infrastructure and maintenance. Currents at a port may be affected by sedimentation around the port. This can help the port authority make intelligent decisions about dredging operations to maintain the minimum depth of the waterway and the stability of the berths. It will also help in the future expansion and development plans for the port, such as new berth construction or facility relocations, by understanding how currents will affect the seabed and general environment of the facility.

The ADCP offers a more sophisticated and efficient way of measuring currents compared to the traditional methods. It provides real-time and accurate data collection, which is very important for the smooth operation and management of the Durban Port.

3. How do ADCPs using the principle of Doppler work?

The working principle of ADCPs is based on the Doppler effect. They send acoustic signals into the water. These acoustic waves scatter off the moving particles in water, such as suspended sediments, plankton, or small organisms. When these particles are in motion, the frequency of the reflected acoustic waves changes due to the Doppler effect.

This frequency shift is measured by the ADCP, and it uses this to derive the velocity of the moving particles. Since the motion of these particles is linked with the ocean current, the ADCP can then infer the speed and direction of the ocean current.

Ship - borne ADCP in the Port of Durban

The ADCP installed in the shipborne is used within the port. The ship would cross over the waters in the port, while the ADCP sends acoustic signals downwards and sideways. Continuously, it receives data about the currents in the ocean at different depths and the positions the ship travels. One can understand comprehensively the wide area of the port about the current situation.

Fixed ADCP at the Port of Durban

Usually, a fixed ADCP would be installed at a fixed location in the port, either on a pier or something underwater. It will continuously detect the currents of the ocean passing through its position. A fixed ADCP will give out current data in the long run in a steady state for an area of the port. Further, it can be applied to analyze the periodic development and changes of the regular patterns of currents in a given locality.

4. What is required for high-quality measurement of the currents at the Port of Durban?

Material Reliability

For current measurement of high quality in the Port of Durban, the equipment should possess high material reliability. The surrounding environment in the port is very harsh; thus, this equipment may be exposed to seawater, which could be corrosive, and potential mechanical impacts. Therefore, the equipment should be constructed from durable materials that will make it withstand such conditions and ensure a long-term and accurate measurement process.

Small in Size, Light in Weight, and Low in Power Consumption

Smaller size, light weight, and low consumption of power are preferable. A small-sized ADCP would be easier to install anywhere in the port, both on ships and fixed structures, due to its small size. A light-weight device simplifies the transport and installation process by saving labor and costs. This low power consumption means that the equipment can continuously work for long hours with no need to change batteries frequently or to consume high energy, which is the key for long-term and unbroken measurement of current.

Cost-effectiveness

Cost is another important consideration. If the equipment cost is reasonable, large-scale measurement of ocean currents in the port can be enabled. The ADCP casing is preferably made of a titanium alloy. A titanium alloy has a number of advantages: it has high strength, which will make it possible to withstand underwater pressure and mechanical forces that may act on the equipment in the conditions of the port environment; it has excellent corrosion resistance, which will enable the equipment to resist the corrosive effects of seawater for a long time. Besides, compared to the rest of the materials, being relatively light, it has been more suitable to be installed in the port.

5. How to Choose the right equipment for current measurement?

Based on Usage Purpose

The equipment to be used for current measurement in the Port of Durban would depend on their intended usage. In the event that the measurements have to be mobile-that is, the ship needs to navigate in the port-the ship-borne ADCP shall be suitable as it would scan most areas of the port, providing a wider view of the current situation.

The sit-on-bottom ADCP is more suitable for long-term, fixed-point monitoring of a certain area in the port. It remains stationary at a particular location and continuously records the current conditions, thus providing very valuable data for the analysis of local current patterns. If the requirement is to monitor a wider area on the water surface, with some mobility, the buoy-mounted ADCP can be considered.

Based on Water Depth

Besides, different frequencies of ADCPs should be chosen according to the water depth. For water depths within 70m, the 600kHz ADCP is usually a good choice as it provides accurate current profiles in shallower waters. For water depths around 110m, the 300kHz ADCP is more appropriate. And for deeper waters up to 1000m, the 75kHz ADCP is recommended to ensure reliable current measurement results.

There are well - known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese ADCP brand - China Sonar PandaADCP is also worth mentioning. It is made of all - titanium alloy material, combining excellent durability and corrosion resistance with an incredible cost - performance ratio. You can find more information about it on its website:(https://china-sonar.com/).

Here is a table with some well known ADCP instrument brands and models.