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

1. Where is Dighi Port

Geographical Location

The location of Dighi port is in Raigad district, State Maharashtra-India. This was literally situated along the coastline of the Arabian Sea with potentials playing major roles in maritime trade across the region.

Importance of Port

The port is designed to handle a variety of cargo, including containers, bulk cargo such as coal and iron ore, and other general cargo. It acts as an integration point in the trade of Maharashtra with other domestic and international markets. The management of Dighi Port is focused on efficient operations, striving to increase the throughput and productivity. There are teams for different aspects, like vessel traffic management, cargo handling, and security.

Port Facilities

Berths

Dighi Port has a number of berths, which are designed to handle various vessels. In addition, there are berths for medium-sized container ships and bulk carriers. These berths have proper mooring facilities to ensure safe docking and undocking of ships. Advanced fendering systems reduce the impact of ships during berthing operations.

Cargo-handling Equipment

The port has gantry cranes for container handling that are capable of efficient loading and unloading operations. In the case of bulk cargo, there are conveyor systems and grabs. The conveyor systems are designed to transport bulk materials from the ships to the storage areas with minimal spillage and maximum efficiency.

Storage Facilities

There are storage facilities for different cargo types. For containers, there exist well-organized container yards that have a system in place for easy access and storing. For bulk, stockpiles exist with adequate drainage and containment to avoid environmental hazards. Other general cargo is stored in the warehouses that the port has.

Channel and Navigation Aids

The channel of the port is kept to a depth and width that allows for the safe passage of ships. Dredging is done regularly to keep it navigable for vessels with different drafts. Navigation aids like buoys, beacons, and radar systems are installed to guide ships into and out of the port. The radar systems provide real - time information about the position of ships in the vicinity of the port.

2. Importance of Measuring Ocean Currents in Dighi Port

Safety of Vessel Navigation

Ocean current measurements are essential from the perspective of vessel safety. masters of vessels need to know speed and direction of currents while approaching berths or navigating in the channel. A strong cross - current near berth may render docking a dangerous and cumbersome process. For instance, the ability of a ship to dock may need to make alterations in speed and course for smooth and safe docking against a very strong current. Accurate current measurement aids the captain in making better decisions and reducing the risks of collision and other accidents.

Optimization of Port Operations

Current data is critical to optimizing the operations of the port. The understanding of tidal currents and other periodic current systems enables the port authorities to plan ship arrivals and departures. This would allow for effective use of the berths and other facilities. For example, ships can arrive at times when the current is favorable, thus reducing some time spent on loading and unloading. Knowledge of current patterns also helps in planning cargo - handling operations more efficiently, leading to increased productivity.

Environmental Considerations

From an environmental point of view, knowledge of ocean currents is useful in the event of an accidental release of pollutants. Due to the nature of cargo that is handled in the port, such as petroleum products or chemicals, prediction regarding the spread of a spill is important. The data on current can be utilized to rapidly deploy containment and mitigation measures to reduce environmental damage.

3. Working Principle of ADCPs (Acoustic Doppler Current Profiler)

Doppler Principle

ADCPs are based on the principle of the Doppler effect. When an ADCP current profiler emits an acoustic signal into the water, it scatters off the moving particles in the water. The moving water particles, due to the ocean current, will shift the frequency of the reflected acoustic signal received back by the ADCP profiler. This frequency shift, according to the Doppler effect, depends on the velocity of the flow.

Calculation of Current Speed and Direction

By analyzing the magnitude and direction of this frequency shift, it is possible for the ADCP current meter to calculate the current speed and direction at various point in the water column. By transmitting signals at multiple angles and at different depths it can create a profile of the ocean current, showing how it changes with depth.

ADCP Deployment in the Port

Shipborne ADCP

One ADCP flow meter is installed on ships operating in the area of Dighi Port. As the ship moves around the port, the ADCP meter continuously sends acoustic signals into the water from underneath. The movement of the ship allows the ADCP profiler to survey a wide area and collect current data from various locations. For instance, a research or inspection ship with a shipborne ADCP that conducts a routine survey of the port can collect data on the current patterns across many areas of the port, thus giving an overall understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs are installed at pre-specified fixed locations within the port, like on the ocean floor near areas of crucial navigation or at the entry and exit points of the port. These ADCPs will, over a long period of time, continuously monitor the ocean currents at their fixed positions. The data thus collected is useful in analyzing the regular current patterns in specific areas of the port. For example, a bottom-mounted ADCP at the port entrance can measure the currents entering and leaving the port, which will give an idea of the tidal effects and other steady features of flow in that area.

4. Requirements for High-Quality Measurement of Currents in Dighi Port

Equipment Requirements

Material Reliability

For high-quality measurement, equipment should be able to endure these very aggressive marine media. Seawater contains salts and other chemicals that will start corrosive action through time. It also must endure the pressure changes for every water depth and the mechanical forces of waves and currents. Materials for making current-measuring equipment should, therefore, be of high resistance to corrosion and mechanical stress.

Size, Weight, and Power Consumption

Smaller size, lighter weight, and lower power consumption will be preferable. The device should be compact in size for easy installation at various locations in the port: on ships, on fixed structures such as piers, or underwater. Being lightweight, it would present fewer difficulties during installation and in transport. 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-effectiveness

The cost is another important factor: the lower the cost, the more devices the port authority can deploy to measure current and monitor different areas of the port area.

The Advantage of Titanium Alloy for ADCP Casing

The casing of ADCPs is preferably made of titanium alloy. The corrosion resistance of the titanium alloy is very excellent, meaning that even if it has been in seawater for a long period, it can still keep its structural integrity and functionality. Its high strength-to-weight ratio allows for the construction of a durable yet relatively lightweight casing. For instance, the deeper areas of the Dighi port will have higher water pressures, and an ADCP current profiler encased in a casing of titanium alloy will efficiently bear such pressures while maintaining the current measurement accuracy.

5. Current Measuring Equipment Selection

Selection Based on Usage

Shipborne ADCP

Shipborne ADCP is suitable if the aim is to conduct wide-area surveys of the port waters while the ship is in operation. In this way, it can cover different sections of the port while the ship is moving around, hence collecting a large amount of data to provide a comprehensive understanding of the overall current situation in the port. This will be useful to map the general flow patterns and variations across different areas of the port waters.

Sitting-bottom ADCP

In case long-term, fixed-point monitoring of particular places at the port area, for instance, near the main structure or areas with complex behaviors of current, bottom-moored ADCPs become more appropriate. They may continuously record the current data at those fixed positions; therefore, it is rather valuable to learn about the characteristic and changes of local currents over time.

Buoy-mounted ADCP

Where fixed deployment either on the seabed or on ships is not convenient, buoy-mounted ADCPs can be used. They float on the water surface and measure currents in the upper layers of the water column. Being relatively easy to deploy and easily redeployable, they have been considered quite suitable for the monitoring of some dynamic areas or areas difficult to reach inside the port.

Selection Based on Frequency

The ADCPs will be selected based on the water depth of Dighi port. Normally, a 600 kHz ADCP is a good choice for areas with a water depth of up to 70 meters because it can yield quite accurate current measurements in this relatively shallow depth range. In waters up to around 110 meters, a higher-frequency 300 kHz ADCP may be more suitable, and when the depth could extend even to 1000 meters in some especially deep portions of the port, 75 kHz can work much better to perform its reliable profiling of currents against that great depth.

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.