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

1. Where is Piraeus Port

Geographical Location and Significance

Piraeus Port is located in the city of Piraeus, near Athens, Greece. It is one of the most important ports in the Mediterranean and Europe. Its strategic location provides excellent access to the Aegean Sea and serves as a crucial link between Europe, Asia, and Africa.

Role in Global Trade and Transportation

Piraeus has developed into one of the most critical container shipping nodes on a global scale. There is also an important passenger port with many ferry lines to Greek islands and other Mediterranean destinations. It is indicative for the Greek economy and very important for international trade, as it supports the import and export of significant products such as automobiles, electronics, agricultural products, and industrial machinery.

2. Port Facilities

Berths

The port contains a great number of berths of different sizes and depth. There are deep-water berths capable to host the biggest container ships and cruise liners. The state-of-the-art mooring and docking systems equipped these berths. The vessels are protected during the docking and undocking operations with high-quality fenders and bollards.

In general, regular maintenance and dredging operations are performed in order for the berths to serve vessels with different drafts. Consequently, the water depth in front of the berths has been continuously monitored and modified if required to meet the modern vessels' demands.

Cargo - handling Equipment

It has an extensive range of cargo-handling equipment along the quay. Advanced gantry cranes are there for handling containers, which can load and unload containers with high speed. There are also reach stackers and forklifts for moving containers within the port area.

The port has conveyor systems, cranes with different lifting capacities, and specialized equipment for handling other types of cargo such as bulk materials and general cargo, which include automobiles or heavy machinery.

Storage Facilities

The storage facilities of Piraeus Port are quite huge. The container yard is well-organized with an advanced inventory management system for such a huge volume of containers. And also general cargo is stored in warehouses, with adequate ventilation and temperature-control systems for perishable items.

The open-air areas and silos for bulk materials. Hazardous goods storage with all safety and security precautions taken to avert the occurrence of an accident or protection to the environment.

Channel and Navigation Aids

The channel of the port is kept very deep and wide for safe passage of the biggest ships. The navigational aids are through buoys, beacons, and a very sophisticated radar system. The radar system displays real-time information on the position and movement of all vessels in the port area and its vicinity.

This information is very important in preventing collisions and facilitating smooth traffic into and out of the port. The port also uses Vessel Traffic Services, VTS, to manage and monitor the movement of ships.

3. Importance of Measuring Ocean Currents in Piraeus Port

Vessel Navigation Safety

Measuring ocean currents is of utmost importance for the safety of the ships in Piraeus Port. Knowledge of current speed and direction is essential while ships approach berths or navigate through the channel. A strong cross-current near a berth can make docking extremely difficult and dangerous.

For instance, a container vessel of larger size that is approaching a berth against a strong current will have to make very precise adjustments in its speed and angle of approach to ensure smooth and safe docking. Precise current measurements enable the captains of ships to make well-informed decisions and avoid collisions, grounding, and other accidents.

Optimization of Port Operations

Current data is crucial to the optimization of Piraeus Port operations. Understanding tidal currents and other regular flow allows port authorities to better schedule ships' arrivals and departures. This enables more efficient use of berthing resources and effective planning of loading and unloading activities.

For example, it can allow ships to be timed in when the current is favorable, thus saving fuel and time for docking and undocking. This means increased productivity and cost-savings for shipping companies and the port itself.

Environmental Considerations

In the case of an accidental spill of oil or chemicals, knowledge of ocean currents is invaluable. Since a large volume and variety of cargo are handled in the port, including hazardous substances, it is possible to predict the spread of a spill using current data so that quick containment and mitigation measures can be undertaken to minimize environmental damage.

The capability of modeling the spread of pollutants based on prevailing patterns helps in mobilizing the required resources for clean - up operations and protecting the marine ecosystem and coastal areas.

4. Working Principle of ADCPs (Acoustic Doppler Current Profilers)

Doppler Principle

ADCPs work on the principle of the Doppler effect. When an ADCP sends an acoustic signal into the water, it interacts with the moving particles of water. Since the water particles are in motion due to the ocean current, they shift the frequency of the reflected acoustic signal received back by the Acoustic Doppler Current Profiler (ADCP).

This frequency shift is dependent upon the velocity of the water flow, as derived from the Doppler effect. The magnitude of the frequency shift is proportional to the speed of the water particles. In other words, the faster the water is flowing, the greater the frequency shift of the reflected signal.

Calculation of Current Speed and Direction

This it does by analyzing the magnitude and direction of this Doppler frequency shift to arrive at the speed and direction of the ocean current at discrete depths in the water column. The ADCP current profiler sends out signals at multiple angles and different depths to create a profile of the ocean current.

It shows the profile of the current, which changes with depth. For instance, the current could be stronger near the surface and weaker at greater depths, or complex vertical patterns may result from factors such as tidal mixing or the presence of topography underwater.

5. Piraeus Port ADCPs Deployment

Shipborne ADCP

One might install a shipborne ADCP on ships operating in the Piraeus Port area; during its movement around the port, the ADCP is sending continuous acoustic signals down in the water. The moving ship will permit the ADCP flow meter to generate extensive and simultaneous current data from various sub-areas.

For instance, in a normal survey of the port by a research or inspecting ship fitted with a shipborne ADCP, it is able to acquire data on the current patterns across different parts of the port, offering a comprehensive scenario of the water flow situation. This can be used for the updating of nautical charts and real - time provision to other ships.

Fixed ADCP

Fixed ADCPs can be placed at specific, stationary locations within the port, such as on the seabed near important navigational areas or at the entrance/exit of the port. These latter ADCPs continuously monitor the ocean currents at their fixed position over a long period.

The data from fixed ADCPs is very useful in analyzing the regular current pattern in certain areas of the port. For example, a fixed ADCP at the entrance of the port can record incoming and outgoing currents, which provide insights into tidal effects and other persistent flow features in that region. This information can be used to determine the best times at which ships can enter or exit the port based on current conditions.

6. Requirements for High - Quality Measurement of Piraeus Port Currents

Equipment Characteristics

Material Reliability: The equipment must be able to withstand the harsh marine environment. Seawater contains salts and other chemicals that can corrode materials over time. Besides that, the equipment needs to resist the pressure changes at different water depths and the mechanical forces caused by waves and currents.

Size, Weight, and Power Consumption: Smaller in size, lighter in weight, and with lower power consumption. A compact size would enable installations on different locations within the port-whether on vessels, fixed structures like piers, or on the seabed. A lighter weight makes the installation and transportation process easier. The low power consumption ensures that the equipment operates without the need for a power supply, frequent battery replacement, or excess power, and therefore can operate continuously over long periods. This is crucial for long-term monitoring applications.

Cost: Cost is also another significant factor. A lower-cost option allows a port to deploy more measuring devices and monitor current across various areas of the port.

Advantage of Titanium Alloy for ADCP Casing

The casing of ADCPs is preferably made of titanium alloy. Titanium alloy has excellent corrosion resistance, which means it can maintain its structural integrity and functionality even when exposed to seawater for a long time.

Its great strength-to-weight ratio enables a casing that is strong yet relative in light weight. Where deeper parts of Piraeus port provide higher water pressures, an ADCP profiler with its casing made of a titanium alloy will be able to resist such pressures and remain operative with very good accuracy in its current measurements.

7. Selecting Appropriate Equipment for Current Measurement

Usage-Based Selection

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

Sitting - bottom ADCP: In regard to long - term and fixed - point monitoring of a certain place in the port-for example, near important infrastructure or areas with complex current behaviors-a sitting - bottom ADCP is more appropriate. They can continuously record current data at those fixed positions, with valuable insights into the local current characteristics and any changes over time.

Buoy-mounted ADCP: In situations where it is not feasible to install fixed equipment either on the seabed or on ships, buoy-mounted ADCPs can be employed. They float on the water surface and are able to measure the currents in the upper layers of the water column. Relatively easy to deploy and capable of relocation if necessary, they are suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency

The water depth in Piraeus port will form the basis for the choice of frequency for ADCPs. For water with a depth of up to 70 meters, an ADCP with a frequency of 600 kHz normally performs well and can yield quite accurate current measurements in this relatively shallow depth range.

For deeper waters, say up to about 110 meters, an ADCP of 300 kHz is more advisable. And for extremely deep sections of the port with a water depth reaching up to 1000 meters, an ADCP with a frequency of 75 kHz is recommended to ensure reliable profiling of the ocean currents at such great depths.

There are several well - known ADCP 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.