ADCP in ISW Dharamtar Port: Ocean Current Measurement

Explore ADCP's application for ocean current measurement in ISW Dharamtar Port, its working principle, equipment requirements, and selection.

1. Where is ISW Dharamtar Port

Geographical Location

ISW Dharamtar Port is situated in Maharashtra, India. The port is strategically positioned along the coastline, which links it with several shipping lanes and trade routes.

Importance of the Port

The port is important, playing a significant role in local and regional sea trade. It has a certain magnitude and intensity of shipment volume. It deals in several types of cargo: bulk materials like coal, iron ore, but also liquid cargo of petroleum products. The port plays a vital link for industries located in the hinterland to import raw materials and export finished goods.

The management of the port is efficient, with teams dedicated to different aspects such as vessel traffic management, cargo handling, and security. Advanced technologies are used to optimize operations, such as automated cargo-handling equipment and digital communication systems for better coordination between different port functions.

Port Facilities

Berths

The port has berths to handle various vessel sizes and types. Among them are bulk carriers whose berths had been complemented with needed mooring and docking facilities and will not pose any obstruction to safe arrival and departure of the ships. Their respective strong bollards and fenders are very substantial and strong to withstand the potential forces applied by the vessels during operations.

Cargo-handling Equipment

For bulk cargo handling, there are conveyor systems and grabs of large capacity. The conveyor systems efficiently transport the materials from the ships to the storage areas. In the case of liquid cargo, such as petroleum products, pumping and transfer systems are installed. For container handling, there are gantry cranes used for quick and precise loading and unloading of containers.

Storage Facilities

It features spacious storage facilities for various cargo types. For bulk, it has well-planned stockpiles with good drainage and dust-suppression systems to avoid environmental hazards. Liquid cargo is accommodated in storage tanks equipped with safety features like spill-containment barriers and fire-protection systems. In addition, there are container yards and warehouses for general cargo storage.

Channel and Navigation Aids

The channel of the port is maintained to a depth and width considered appropriate for safe navigation; hence, dredging occurs regularly to keep it usable even for vessels with large drafts. Dredging operations are used to keep it usable at all times for vessels with heavy drafts. Navigation aids buoy, beacons, and radar systems are installed to guide incoming and outgoing ships. Radar information provides real-time position as well as movement of other craft in the vicinity.

2. Importance of Measuring Ocean Currents in ISW Dharamtar Port

Safety of Vessel Navigation

Ocean current measurement is very important from the point of view of safety of ships. The captains must know the speed and direction of currents while approaching the berths or navigating through the channel. A strong cross - current near a berth can make the docking process very difficult and dangerous. For instance, when it is docking against a remarkable current, it needs to adjust speed and course in order to make docking smoother and safe. Current accurate measurements assist the captains to make more precise decisions on how to handle collisions or accidents.

Optimization of the Port Operations

Current data aids in optimizing the operations of a port. By understanding the tidal currents and other regular flow patterns, the port authorities can schedule the arrival and departure of ships more effectively. This will also allow better utilization of the berths and other resources. For example, ships can be timed to arrive during periods of favorable currents, which can speed up the loading and unloading process. Knowledge of current patterns also helps in planning cargo-handling operations more effectively, thus increasing the output.

Environmental Considerations

From an environmental point of view, knowledge of ocean currents would be useful in case any accidental spill of pollutants has occurred. Considering the kind of cargo handled at the port, such as petroleum products, it becomes paramount to predict the spread in case of a spill. The current data can then be used to quickly deploy containment and mitigation measures to reduce the environmental damage.

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

Doppler Principle

Working principle: the ADCPs rely on the principle of the Doppler effect. A projected acoustic signal by the ADCP meter in the water interacts with moving particles of the water. As the movement of water particles is basically because of ocean currents, that reflection which they cause lags or leads regarding its frequency of the sound signal reaching again to the ADCP profiler. Frequency shift in a reflected sound wave received has been related by the Doppler effect to its velocity.

Speed and Direction Calculation: By analyzing the amplitude and direction of this Doppler shift frequency, the ADCP flow meter is able to obtain the current speed and direction at various levels in the water column. Because signals are transmitted at several directions and at multiple depths, it can develop a profile of the ocean current - showing how the current changes with depth.

ADCP Deployment in the Port

Shipborne ADCP

An Acoustic Doppler Current Profiler (ADCP) is installed on board a ship operating within the ISW Dharamtar Port area. During its travel over the port, the ADCP current meter continuously emits acoustic signals into the water underneath the ship. Its movement over the port provides the ADCP profiler with current data for large areas of the port. For instance, during a routine survey of the port by a research or inspection ship that is fitted with a shipborne ADCP, it can acquire data from the current patterns across various parts of the port, therefore giving an overall view of the water flow situation.

Fixed ADCP

Fixed ADCPs are deployed in certain fixed locations within the port, like on the ocean floor near areas of importance for navigation or at the entrance/exit of the port. These ADCPs continuously monitor the ocean currents at their fixed positions over a long period. This will help in analyzing the regular current patterns in specific areas of the port. For example, a bottom-mounted ADCP at the entrance can measure the in and out flowing currents to determine the tidal effects and other regular flow features of that area.

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

Equipment Requirements

Material Reliability

The equipment has to be resistant to the harsh marine environment for high-quality measurement. Seawater contains salts and other chemicals that can cause corrosion over time. The equipment also needs to endure pressure changes at different water depths and the mechanical forces caused by waves and currents. Therefore, the materials used in the construction of current-measuring equipment should have high resistance to corrosion and mechanical stress.

Size, Weight, and Power Consumption

Smaller size, lighter weight, and lower power consumption are preferred. A smaller size enables installation in most locations around the port, whether on vessels, fixed structures such as piers, or underwater. A lighter weight simplifies installation and transportation. 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

Cost is also a significant factor. A lower - cost option 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 Casing

ADCP current meter casings are made preferably from titanium alloy. Titanium alloy has excellent corrosion resistance, which means it maintains its structural integrity and functionality even when exposed to seawater for a long period of time. Its high strength-to-weight ratio allows the building of a durable yet relatively lightweight casing. For instance, at the bottom of the deeper parts of the ISW Dharamtar port where higher water pressures are prevalent, an ADCP current profiler made of a casing in a titanium alloy can withstand such pressures without breaking down while continuously giving accurate current measurements.

5. Selection of Appropriate Equipment for Current Measurement

Selection Based on Usage

Shipborne ADCP

If the aim is to conduct wide-area surveys of the port waters while the ship is in operation, then a shipborne ADCP is suitable. It can cover different sections of the port as the ship moves around, collecting a large amount of data to provide a comprehensive understanding of the overall current situation in the port. This serves to map the general flow patterns and variations across different areas of the port waters.

Sitting-bottom ADCP

In cases of long-term and fixed-point monitoring in the port area, such as around key infrastructure or locations with complex current behaviors, bottom-sitting ADCPs are more appropriate. They can record continuously the current data at those fixed positions, thus providing valuable information about the local current characteristics and changes over time.

Buoy-mounted ADCP

They may be buoy-mounted when it is inconvenient or not possible to install the fixed equipment on the seafloor or vessels; buoy-mounted ADCPs are floating on the surface, thus measuring the currents from the upper layers of the water column. Being comparatively easy to set up, if necessary, these could similarly be relocated for some monitoring processes of dynamic areas, not accessible, incoherent, or problematic.

Frequency Selection

Selection of frequency for ADCPs depends on the water depth in ISW Dharamtar port. For a water depth up to 70 meters, an ADCP flow meter with a frequency of 600 kHz is generally preferred because it can deliver accurate current measurements in this relatively shallow depth range. In waters up to about 110 meters, an ADCP profiler of around 300 kHz is highly recommended. And for the extremely deep areas in the ports, going to a maximum of about 1000 meters depth, the right choice could be an ADCP working on 75 kHz that can comfortably yield good profiling of the ocean currents at large 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.

Brand model
Teledyne RDI Ocean Surveyor ADCP, Pinnacle ADCP, Sentinel V ADCP, Workhorse II Monitor ADCP, Workhorse II Sentinel ADCP, Workhorse II Mariner ADCP, Workhorse Long Ranger ADCP, RiverPro ADCP, RiverRay ADCP, StreamPro ADCP, ChannelMaster ADCP, etc.
NORTEK Eco, Signature VM Ocean, Signature ADCP, AWAC ADCP, Aquadopp Profiler, etc.
SonTek  SonTek-RS5, SonTek-M9, SonTek-SL, SonTek-IQ, etc.
China Sonar PandaADCP-DR-600K, PandaADCP-SC-300K, PandaADCP-DR-300K, PandaADCP-SC-600K, PandaADCP-DR-75K-PHASED, etc.
Jack Law September 7, 2024
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