ADCP's Application to Ocean Current Measurement in the Port of Mumbai

1. Where is Mumbai Port?

Overview of Mumbai Port

Mumbai Port is one of the most significant ports in India, located on the west coast of the country. It has a vast scale and a long history of maritime trade. The port's throughput is substantial, handling a wide variety of cargo such as containers, bulk cargo including grains and minerals, and liquid cargos like petroleum products.

The shipping routes of Mumbai Port connect it with almost all major and minor ports around the world. This port acts as an important entry point for foreign trade. It has much importance in the import and export mechanism of different commodities. The functioning and management mechanism of the port is well-organized and effective. It possesses specific teams for different tasks, such as vessel traffic control, cargo handling mechanism, and customs clearance mechanism. Advanced technologies include automated cargo-tracking systems to optimize the flow of goods and vessels, and digital communication platforms to better coordinate.

Port Facilities

Berths: The port has several berths with varying depths and lengths for receiving different-sized ships. It has deepwater berths for big container ships and tankers and smaller berths for coastal vessels or feeder ships. These have modern mooring and docking facilities to handle the safe arrival and departure of vessels.

Cargo-handling Equipment: There is a range of cargo-handling equipment along the quay. These include high-capacity gantry cranes for handling containers, which ensure speedy loading and unloading; conveyor belts, grabs, and other specialized equipment for bulk cargo; and pumping systems with pipelines for efficient transfer in the case of liquid cargos.

Storage Facilities: The storage facilities at the Port are enormous and cater to various cargo types. Large-scale container yards are present with efficient stacking systems. The bulk cargo has stockyards and silos, while liquid cargos have storage tanks equipped with safety features like spill-containment systems and fire-protection systems.

Channel and Navigation Aids: The channel of the port is dredged to have a depth and width that is appropriate for big vessels. Dredging is done on a regular basis to keep it well navigable. Navigation aids such as buoys, lighthouses, and radar systems have been installed to help ships move in and out of the port safely.

2. Why must we measure the ocean currents in Mumbai Port?

Importance to Port Operations and Management

Measurement of ocean currents at Mumbai Port is necessary for more reasons: to ensure vessel navigation safety, knowledge about the speed and direction of flow develops the current when a captain is approaching the berths or navigating through narrow channels. A strong cross-current near a berth can make docking a challenging and dangerous process. Accurate current measurements allow captains to adjust the ship's course and speed, ensuring a smooth and safe docking and reducing the risk of collisions.

It is important for optimizing the operation of a port. Currents with current data develop better scheduling of ships' arrival and departure. With knowledge about tidal currents along with other regular current patterns, it will be easier for the port authorities to manage the berthing resources in a far superior manner and plan the activities related to the loading and unloading. It results in enhanced productivity by enabling the better coordination of cargo-handling operations.

Further, from the point of view of ecology, knowledge about ocean currents can provide an opportunity to predict the process of spreading in case of an accidental spill. Since the cargoes handled within the port include potentially hazardous substances, this information enables rapid intervention to contain and mitigate the environmental damage. Considering these relevant factors, the use of a correct and easy measurement technique such as the ADCP, or Acoustic Doppler Current Profiler, is quite useful in the measurement of ocean currents at Mumbai Port.

3. How Do ADCPs Employing the Doppler Principle Work?

Measurement Principle

ADCPs are based on the principle behind the Doppler frequency shift. The acoustic signal transmitted into the water by the ADCP flow meter interacts with the moving particles in the water. Since the water particles are moving due to the ocean current, they create a Doppler shift in the frequency of the reflected acoustic signal that is received back by the ADCP profiler. This frequency shift has a relationship with the velocity of the water flow, as defined by the Doppler effect. Based on this, the frequency shift will be used by the ADCP current profiler to calculate the speed and direction of the water flow. By transmitting signals at several angles and over different depths, the ADCP current meter can ultimately be able to give a profile of the current in the ocean by showing how the current changes over depth.

ADCP in Port Ocean Current Measurement Methods

Shipborne ADCP: Shipborne ADCPs are fitted on ships serving in the Mumbai Port area. Motion of the ship around the port confronts the ADCP meter with continuous transmission of acoustic signals into the water below it. The moving of the ship enables the ADCP profiler to cover large areas and obtain current data from various locations. For instance, in a regular survey of the port by a research or inspection ship fitted with a shipborne ADCP, it is able to collect data on the current patterns across various parts of the port, thus giving a comprehensive understanding of the water flow situation.

Fixed ADCP: Fixed ADCPs are deployed on-site at fixed positions around the port, like on the seabed near important navigational areas or at the entrance/exit of the port. These continuously monitor the ocean currents at the same place over a longer period. The collected data thereby serves for analyzing the regular current pattern in particular areas of the port. A single ADCP current meter fixed at the port entrance can measure the incoming and outgoing currents, for example, which helps in understanding the tidal effects and other consistent flow characteristics of the region.

4. What does one need to obtain quality measurement of currents at Mumbai port?

Equipment Requirements

Basically, some of the quality measurement features of currents in Mumbai port require material reliability. The equipment should also be resistant to corrosion presented by seawater or any other deteriorating factor. Seawater consists of salts and some chemicals that can easily corrode metals over some time. It must be strong enough to bear the differences in pressure at different water levels and the force exerted by waves and currents.

It is desirable that it has a smaller size, lightweight, and reduced power consumption. The small sizes are needed for easy installation in different locations within the port, whether on the vessels, on fixed structures like piers, or on the seabed. The lighter weight also makes installation and transportation easier. Lower power consumption ensures that the equipment can operate continuously for long periods without the need for frequent battery replacements or excessive power supply, which is especially important for long - term monitoring applications.

Cost is also a significant factor. A lower cost enables the port to deploy a larger number of measuring devices for more comprehensive current monitoring across different areas of the port.

The Advantage of Titanium Alloy for ADCP Casings

The casing for ADCPs is preferably made from titanium alloy. Corrosion resistance of titanium alloy is excellent; its structural integrity and function can be retained even after long exposure to seawater. Its high strength-to-weight ratio enables the construction of a durable yet relatively lightweight casing. For example, in deeper areas of the Mumbai port where the water pressures recorded are significantly higher, an ADCP flow meter casings with a base made of a titanium alloy can withstand these pressures and perform with increasingly accurate current measurements.

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

Selection Based on Usage

Shipborne ADCP: Where the aim is to carry out wide-area surveys of the port waters while the ship is in operation, it would be advisable to use shipborne ADCP. With the ship moving around, it can cover different sections of the port while continuously collecting a lot of data for a comprehensive understanding of the overall current situation in the port. This serves to map the general pattern of flow and variations between different areas of the port waters.

Sitting-bottom ADCP: Whenever long-term and fixed-point monitoring at certain places within the port or near infrastructures, areas with complex behaviors of current are concerned. Again, sitting bottom ADCPs are applicable for continuously recording the current data at fixed positions, which offers important information about the local characteristics of current and their possible variation in time.

Buoy - mounted ADCP: When it is not convenient to install fixed equipment on the seabed or on ships, buoy-mounted ADCPs can be used. They float on the water surface and can measure the currents in the upper layers of the water column. They are relatively easy to deploy and can be relocated if needed, making them suitable for monitoring certain dynamic or hard - to - reach areas within the port.

Frequency Selection

The choice of frequency for ADCPs depends on the water depth in Mumbai port. For areas with a water depth of up to 70 meters, an ADCP profiler with a frequency of 600 kHz is generally a good choice as it can very well record current measurements in this relatively shallow depth range. When operating in deeper waters of up to about 110 meters, a 300 kHz frequency ADCP meter would be more appropriate. In very deep areas of the port, reaching water depth of up to 1000 meters, an ADCP flow meter with 75 kHz is advisable to ensure reliable profiling of the currents at such great depths of the ocean.

There are several well - known ADCP current meter brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCP brand - China Sonar PandaADCP. It is made entirely of titanium alloy material, which not only ensures its durability in the marine environment but also offers an excellent cost - performance ratio. For more information, you can visit its official website: (https://china-sonar.com/).

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