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

1. Where is Paloukia Port

Location and Significance

Paloukia Port is probably a smaller - scale port in Greece, though not as famous as some major Greek ports. It is located in a coastal area serving local and possibly some regional maritime traffic.

Role in Local Trade

The port is vital to the local economy. It primarily deals in local agricultural produce like fruits, vegetables, and grains for transportation to nearby markets. It may also deal with small-scale shipments of construction materials and other essential goods needed in the surrounding areas.

2. Port Facilities

Berths

The port has some berths, which are meant for accommodating vessels of small to medium sizes. These berths are equipped with basic mooring and docking facilities. The fenders and bollards protect the ships during the processes of docking and undocking.

Water depth at the berths is maintained to an optimum level to ensure the safe docking of the ships that generally visit the port.

Cargo - handling Equipment

Along the quay, there is a range of cargo - handling equipment. For agricultural products, forklifts and simple conveyor belts are used to move the goods from the ships to the storage areas. For construction materials, small cranes and pallet jacks are available.

There are also storage bins and hoppers for bulkier materials to facilitate efficient handling.

Storage Facilities

Storage facilities are provided, including a variety of different cargo. In regard to agricultural produce that can spoil quickly, storage exists in well-ventilated warehouses; cold storage basic-type facilities provide additional backup on occasion for freshness of produce. Then there is open air and under partial cover for building supplies as well as non-perishable materials.

Channel and Navigation Aids

The channel of the port is kept to a depth and width to enable the safe passage of the ships it serves. There are also navigational aids like buoys and simple beacons to guide the ships into and from the port. A simple radar system might be installed to monitor the vessels moving around it.

3. Importance of Measuring Ocean Currents in Paloukia Port

Vessel Navigation Safety

Ocean current measurement is highly important for the safety of ships that dock in and depart from Paloukia Port. When a ship approaches a berth, the speed and direction of the current are of utmost importance. A cross - current can make the docking process quite difficult and risky.

For instance, a ship approaching a berth at an angle to a strong current may well have to adjust its speed of approach and angle of approach for safe and smooth docking. These accurate current measurements allow the captains to make better informed decisions and reduce the risks associated with collisions and other accidents.

Optimization of Port Operations

Current data is useful for the optimization of operations at Paloukia Port. Understanding the tidal currents and other regular flow patterns enables port authorities to schedule the arrival and departure of ships better.

It would result in efficient usage of the berthing facility and also pave the way for proper planning of the loading and unloading activities. This can contribute to a rise in the overall productivity of the port by developing better coordination of cargo-handling operations.

Environmental Considerations

In the event of an accidental spill from vessels carrying oil or chemical pollutants, knowledge of the ocean currents is essential. Considering the type of cargo moved within the port, a forecast of the trajectory of a spill using current data can be effective in rapid deployment and mitigation processes to reduce environmental impact.

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

Principle of Doppler

ADCPs work on the principle of the Doppler effect. When an ADCP sends an acoustic signal into the water, it scatters off the moving water particles. Due to the ocean current, these water particles are in motion and, therefore, the reflected acoustic signal received back by the ADCP is shifted in frequency.

This frequency shift is dependent on the velocity of the water flow, according to the Doppler effect. The larger the speed of the water particles, the greater the frequency shift of the reflected signal.

Calculation of Current Speed and Direction

The ADCP calculates the velocity of the ocean current, both in speed and direction at discrete points along its depth profile, by the amount of this frequency shift in its direction.

Thus, the ADCP flow meter does a lot of signal broadcasting on every different angle, going at each depth. Thus, a profile shows up depicting the variation in ocean currents with depth that in real life will provide comprehensive information on the current structure.

5. Acoustic Doppler Current Profiler (ADCP) Deployment in Paloukia Port

Shipborne ADCP

The shipborne ADCP could be installed on ships that normally operate in the Paloukia Port area. While the ship cruises around the port, the ADCP sends continuous acoustic signals to the water below it. Due to the ship movement, the ADCP current meter is able to survey a big area and take current measurements from various places.

For instance, during a routine survey of the port by a research or inspection ship fitted with a shipborne ADCP, it is able to obtain current pattern data across many different areas of the port and can develop a full picture of the water flow situation.

Fixed ADCP

The fixed ADCPs can be installed in stationary positions inside the port-for instance, at the bottom of the seabed, close to an important navigation area or at the entrance/exit of the port. In fact, such ADCPs monitor the current of the ocean continuously in a fixed position for a long time.

The data from fixed ADCPs can be used to analyze the periodic current patterns in certain areas of the port. For example, a fixed ADCP installed near the entrance of the port will record the incoming and outgoing currents, thus helping to understand the tidal effects and other consistent flow characteristics in that area.

6. Requirements for High - Quality Measurement of Paloukia 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. It also needs to endure pressure changes at different water depths and the mechanical forces from waves and currents.

Size, Weight, and Power Consumption: Smaller size, lighter weight, and lower power consumption are desired. Compact size for easy installation at any of various port locations, on ships, at piers, or at the seabed floor; light weight is good for easier installation and transportation. With low power consumption, devices can keep working continuously without changing the batteries or getting excessive power supply, which is very important for long-term monitoring.

Cost: Cost is a major factor. A lower-cost alternative will allow the port to deploy more measuring devices for the current monitoring in greater detail over 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 can maintain its structure and function without being damaged for a long time in seawater.

Its high strength-to-weight ratio allows for the design of a robust yet fairly lightweight casing. An ADCP in the deeper areas of Paloukia port where water pressure is greater, with a casing made from a titanium alloy, would be able to hold the pressure and make quite accurate current measurements.

7. Current Measurement Equipment Selection

Application-Based Selection

Shipborne ADCP: If the objective is to carry out wide-area surveys of the port waters during vessel operation, then shipborne ADCP is quite suitable. In this case, it would cover different sections of the port as the ship moves around, collecting a large amount of data to provide an overall understanding of the current situation in the port. This is useful for mapping general flow patterns and variations.

Sitting-bottom ADCP: Used for long-term and fixed-point monitoring of specific locations in the port, such as near important infrastructures or areas with complex behaviors of current, sitting-bottom ADCPs are more applicable. They can record, continuously, the current data at the fixed positions, thus reflecting not only the local characteristics but also the changes of these currents with time.

Buoy-mounted ADCP: This is applied when the installation of fixed equipment on the seabed or vessels is not convenient. They float on the water surface and measure currents in the upper layers of the water column. They are relatively easy to deploy and can be relocated, making them suitable for monitoring dynamic or hard-to-reach areas.

Selection Based on Frequency

The choice of frequency for ADCPs depends on the water depth in Paloukia port. For areas with a water depth of up to 70 meters, an ADCP with a frequency of 600 kHz is usually a good choice for accurate current measurements.

For deeper waters, at depths of approximately 110 meters, a frequency of 300 kHz would be more advisable. In a few very deep parts with water depth up to 1000 meters, one would recommend using an ADCP with a frequency of 75 kHz for valid profiling of ocean currents.

There are well - known ADCP brands like Teledyne RDI, Nortek, and Sontek. Additionally, there is an excellent Chinese ADCP brand - China Sonar PandaADCP. It is made of titanium alloy, ensuring durability in the marine environment and offering a good cost - performance ratio. For more information, visit its official website: (https://china-sonar.com/).

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