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

1. Location and General Information about Perama Port

Geographical Location

Perama Port - Greece, near Athens. It holds quite a good record in the respective area and enjoys its status due to proximity to the capital and other big cities.

Role in the Maritime Industry

The port is a major hub for shipbuilding and ship repair. It also handles a variety of maritime-related services such as yacht maintenance and the docking of smaller vessels. In addition to these activities, it is involved in the transportation of goods such as marine equipment, construction materials for the shipyards, and supplies for the vessels being repaired or maintained.

2. Port Facilities

Berths

The port has a number of berths designed to accommodate different types of vessels. There are berths that can suit small to medium-sized ships, yachts, and workboats. These berths are equipped with mooring and docking facilities to ensure the safe arrival and departure of vessels. Fenders and bollards will protect the ships and the berths during the operations of docking and undocking.

The depth of water at the berths is kept suitable for the vessels that regularly come to the port. This might entail frequent dredging operations to allow ships of different drafts to come to the berths.

Cargo-handling Equipment

Along the quay, different cargo-handling equipment is available, such as cranes and forklifts for the transportation of heavy marine equipment and construction materials. Even conveyor belts are used when handling bulkier materials like sand or gravel used in ship repair or building.

For smaller items and supplies, there are pallet jacks and other material - handling equipment to facilitate efficient loading and unloading of goods.

Storage Facilities

There are storage areas for different types of cargo. For marine equipment and spare parts, there are warehouses with organized shelving and inventory management systems. For construction materials, there are open-air stockpiles and covered storage sheds to protect the materials from the elements.

The port also has storage areas for fuel and other hazardous substances, with appropriate safety measures such as fire - suppression systems and spill - containment barriers.

Channel and Navigation Aids

The channel of the port is kept at a proper depth and width to ensure that ships pass through it safely. Navigation aids include buoys, beacons, and a radar system. The radar system shows real-time information on the position and movement of other vessels in the vicinity of the port, enabling safe navigation.

3. Importance of Measuring Ocean Currents in Perama Port

Vessel Navigation Safety

Measurements of the ocean currents are also important for the safety of vessels in Perama Port. It will be necessary to know the speed and direction of currents when ships come to the berths or are heading through the channel. A cross-current near a berth can make the process of docking hard and dangerous.

For instance, a vessel approaching a berth against a strong current has to adjust its speed and angle of approach to ensure smooth and safe docking. Precise current measurement enables captains to make informed decisions and minimize the possibility of collision and accidents.

Optimization of Port Operations

Current data is of high value in the optimization of operations of Perama Port. From a knowledge of tidal currents and other periodic flow patterns, the port authorities will be better able to schedule ship arrivals and departures.

In this way, it is possible to have a much more efficient use of the berthing resource and also a better scheduling of the loading and unloading activities. As such, increased productivity is achievable through the better coordination of cargo-handling operations.

Environmental Considerations

In the event of a spill of pollutants like oil or chemicals, ocean currents studies become crucial. Since the cargo moved in and out of the port is of a nature that can lead to an accidental spill, it would be helpful to predict the path of the spill based on current data for containment and mitigation to minimize damage to the environment.

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

Doppler Principle

ADCPs work on the basis of the Doppler principle. Whenever an Acoustic Doppler Current Profiler (ADCP) sends an acoustic signal into the water, it bounces back after interacting with the moving water particles. The reflected acoustic signal received back by the ADCP undergoes a frequency shift because the water particles, due to the ocean current, are in motion. According to the Doppler effect, this frequency shift is related to the velocity of the water flow. The larger the speed of the water particles, the larger the frequency shift of the reflected signal.

Calculation of Current Speed and Direction

By analyzing the magnitude and direction of this frequency shift, the ADCP meter can compute the speed and direction of the ocean current at a variety of depths in the water column.

Multiple signals are sent out by an ADCP current meter at different angles and depth to create an ocean current profile. That gives one an idea about how the current changes with depth for a detailed interpretation of the current structure.

5. Deployment of ADCPs in Perama Port

Shipborne ADCP

The shipborne ADCP is mounted on ships plying around the Perama Port area. During the movements of the ship, the ADCP flow meter continuously emits acoustic signals down into the water. Its movement results in covering a broad area whereby the ADCP measures current at various locations. For instance, in a normal study of the port by a research vessel or an inspection vessel installed with a shipborne ADCP during its regular survey of a port, it can gather data on the current pattern over the different parts of a port for a complete insight into the water flow condition.

Fixed ADCP

Fixed ADCPs can be placed at certain fixed positions within the port, for example, on the seabed near important navigation areas or at the entrance/exit of the port. The ADCPs continuously monitor the ocean currents at their fixed positions over a long period.

The data obtained from fixed ADCPs can be used to study the periodic current conditions in certain areas of the port. For example, a bottom-mounted fixed ADCP placed near the entrance of the port can measure the currents going in and out, and it can provide information about the tidal effects and other steady flow features of that area.

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

Equipment Characteristics

Material Reliability: It should be capable of sustaining the mean conditions of sea water, which includes other chemical contents that may corrode the material over time. It should also be able to endure different pressures at greater depths of water and the mechanical forces from waves and currents.

Size, Weight, and Power Consumption: Smaller in size, lighter in weight, and with lower power consumption. The small size makes it easy to install at various port locations such as on ships, piers, or even on the seabed. A lighter weight simplifies installation and transportation. Low power consumption ensures that it will continuously work for long periods without needing to change the batteries or have excessive power supply, which is important for long-term monitoring.

Cost: Cost is a major factor. A lower-cost alternative would allow the port to deploy more measuring devices for extensive current monitoring in 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, maintaining its structural integrity and functionality when exposed to seawater for a long time.

High strength-to-weight ratio allows for the building of a durable yet relatively lightweight casing. In deeper areas of Perama, where water pressure is much higher, an ADCP with a casing made from a titanium alloy would surely outlast the pressure and also provide current measurement data as accurate as it gets.

7. Selecting the Appropriate Current Measurement Equipment

Application-Based Selection

Shipborne ADCP: This could be used if one is interested in conducting wide-area surveys of the port waters when the ship is in operation. It covers different sections of the port as it moves around, gathering enormous amounts of data that are then integrated to develop an overview of the general current situation at this particular port. This is useful for mapping general flow patterns and variations.

Sitting-bottom ADCPs: They would be more applicable in long-term, fixed-point monitoring for specific locations in the port, for example, near infrastructure of special importance or places where the behavior of the currents is too complex. This kind of instrument could continuously record data on the currents at fixed positions and allow an analysis of local characteristics of current and time changes.

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

Selection Based on Frequency

Based on the water depth in the port of Perama, the frequency for ADCPs is chosen. In cases of a water depth of up to 70 meters, generally, an ADCP with 600 kHz is suitable for better current measurements.

For deeper waters up to about 110 m, it is more advisable to use an ADCP of 300 kHz. And for very deep sections in the port with water depth reaching up to 1000 m, it is recommended to use an ADCP with a frequency of 75 kHz for reliable profiling of the 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.