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

1. Where is the Port of Paljassaare?

The Port of Paljassaare is situated in Tallinn, Estonia. It is a major local port, serving a multitude of purposes for the region's maritime activities.

Port Scale and Throughput

It has a scale that is relatively small to medium in size. The composition of its throughput is mainly local and regional trade goods, including construction materials, agricultural products, and some industrial supplies. It also acts as a place of docking for smaller vessels, such as fishing boats and pleasure crafts. Its capacity is built for traffic from these smaller to medium-sized ships to serve the economic activities of the surrounding regions.

Routes and Business Paljassaare port is connected with the local and regional shipping routes. Domestically, the port is connected with other various Estonian ports for the distribution of goods. Regionally it falls under the Baltic Sea trade network, facilitating trade with neighboring countries such as Finland and Sweden. The businesses carried out include general cargo handling, supporting fishing activities, and offering berthing facilities for small commercial and recreational vessels.

Port Management and Operation

The port is managed by a team of professionals who oversee all aspects of its operation. They are responsible for arranging berthing for different types of vessels, coordinating the loading and unloading of cargo, and maintaining the safety and security of the port area. The management also works in cooperation with local service providers, such as stevedoring companies and customs officials, to ensure smooth and efficient operations.

Port Facilities

It has basic to intermediate-level facilities. There are variously-sized berths to handle different types of vessels. The port has cargo-handling equipment such as cranes and forklifts to assist in the transfer of goods. There are storage areas for temporary warehousing of cargo and facilities for refueling and basic maintenance of ships.

Channel and Direct Navigation

The port has a channel kept at a reasonable draught, allowing ships to safely come in and leave the place. The channel is dredged as needed to keep it at the proper depth for vessels transiting through. Buoyage and lights exist that guide the ships during approach and departure, providing straight navigation for vessels from any other direction in the Baltic Sea.

2. Why measure the ocean currents of the Port of Paljassaare?

Navigation Safety

Measuring ocean currents in the Port of Paljassaare is very important for the safety of ships. Knowledge of current patterns helps ships, especially smaller vessels with less power and maneuverability, to navigate safely in and out of the port. Unpredictable or strong currents may lead to accidents such as collisions with other vessels or running aground. By having accurate current data, ship captains can adjust their speed and course to avoid such risks.

Efficient Port Operations

It is also beneficial for the efficient operation of the port. Understanding the ocean currents allows for better scheduling of ship arrivals and departures. Ships can take advantage of favorable currents to reduce fuel consumption during docking and undocking. This can lead to more efficient use of port resources and shorter waiting times for ships.

Environmental Protection

From an environmental point of view, the present measurements of current are relevant. Currents can affect the dispersion of pollutants such as oil spills or wastewater discharges. In case of an accident or routine discharge, knowing the current patterns helps in implementing effective containment and clean - up measures. This minimizes the impact of pollutants on the marine environment and the surrounding coastal areas.

Infrastructure Maintenance

For the long - term planning and maintenance of port infrastructure like breakwaters and quay walls, current data is vital. The forces exerted by ocean currents over time can cause damage to these structures. ADCP current meter provides a more advanced and convenient way to measure ocean currents compared to traditional methods, offering detailed and real - time information about current profiles at different depths.

3. How do ADCPs applying the Doppler principle operate?

ADCPs work on the principle of the Doppler effect. They send acoustic signals into the water. As these acoustic waves encounter moving particles in the water-sediment particles, plankton, or other small organisms carried by the ocean current-the frequency of the reflected waves changes. This change in frequency, known as the Doppler shift, is directly related to the velocity of the moving particles and thus the velocity of the ocean current.

Typically, ADCPs are configured with several transducers oriented to emit and receive these acoustic signals in multiple directions. The ADCP current profiler estimates the speed and direction of the ocean current at several depths by measuring the Doppler shift from several directions - normally in a three- or two-dimensional configuration.

ADCP for Port Ocean Current Measurement: Shipborne ADCP

Shipborne ADCPs are mounted on vessels. The ADCP flow meter continuously sends acoustic signals downward and to the side while the ship is underway. It gathers information on the current velocity as the ship moves across various parts of the port. The major advantage with this technique is that it is mobile and can take measurements over a wide range of locations within the waters of the port. However, it is necessary to account for the ship's own motion to obtain accurate results. These methods include calibration and compensation for the errors introduced by the movement of the ship.

Fixed ADCP

Fixed ADCPs are deployed at fixed locations in the port, either on the seabed or on fixed structures such as piers or buoys. They monitor the ocean current continuously at that fixed point over a long period. This provides long-term and consistent data for understanding the regular current patterns in a specific area of the port. The disadvantage is that they only cover a limited area around their installation location, but they are very useful in establishing reference current data for particular regions within the port.

4. What's needed for high-quality measurement of Paljassaare Port currents?

Reliable Equipment Materials

The materials of equipment for reliable measurement of the ocean current in the Port of Paljassaare should be quality. Due to the corrosiveness of seawater and possible actions of floating junk, material should be strong enough. According to the present conditions, the equipment should be made to bear up to Baltic Sea's marine conditions and stay functional for several years.

Compact and Lightweight Design The size of the equipment should be small to enable easy installation, particularly in areas where there is little room for it, such as on small buoys or in regions with complex underwater structures. A lightweight design is also advantageous in that it makes the installation and maintenance processes easier.

Low Power Consumption

Low power consumption is critical, especially for long - term monitoring. Equipment with high power requirements may face significant challenges in maintaining continuous operation, either due to limited power supply options in the port area or frequent battery replacements.

Cost-Effectiveness

Cost-effectiveness is another factor: for example, less expensive equipment to measure currents comprehensively in the port enables more deployments and can give a better understanding of current conditions throughout the waters of the port.

The casing of ADCP profiler is preferably made of titanium alloy. Titanium alloy has excellent corrosion resistance in seawater, ensuring the longevity of the equipment. It is also relatively strong and lightweight, capable of withstanding high pressures at greater depths without adding excessive weight to the device. Besides, its biocompatibility means that it is less likely to cause adverse effects on the marine environment or interfere with the acoustic signals used by the ADCP meter.

5. How to Choose the right equipment for current measurement?

Based on Usage Purpose

• Shipborne ADCP: If the intention is to obtain current data over a wide area of the port while the ship is in operation-for example, during regular port surveys or when collecting data for navigational chart updates-shipborne ADCPs can be used. They can cover different parts of the port as the ship moves around.
• Bottom - mounted (Sitting) ADCP: When the nature of monitoring requires long-term and fixed-point monitoring of specific locations within the port, such as near critical infrastructure like breakwaters or at the entrance of the port channel, bottom-mounted ADCPs are suitable. They provide stable and continuous data for understanding the local current characteristics.
• Buoy-mounted ADCP: When there is inconvenience in the installation of fixed equipment on the seabed or on structures, or when surface and near-surface current conditions need to be captured with a floating monitoring point, the way to go is buoy-mounted ADCPs.

Based on Different Frequencies

• For water depths within 70m, a 600kHz ADCP will often be a good option. It can provide relatively high-resolution current profiles in shallower areas, suitable for many parts of the port where the water depth is not extremely deep, such as near the quay walls or in the inner harbor.
• The ADCP of 300kHz will be more appropriate in dealing with water depths of up to 110m; this will effectively penetrate the water column at these depths and is quite accurate in measuring current velocities.
• The areas of much deeper regions in the approach channel to a port, where water can go beyond 1000 m deep, require a lower-frequency device: a 75 kHz ADCP. That one could reach greater depths with some valuable information regarding the currents.

There are a number of well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. In case one wants a cost-effective option with very good quality, the China Sonar PandaADCP should be a good choice. The materials it is made of are of all-titanium alloy, with a combination of strength and good performance. For the given task, the incredibly good cost-performance ratio offers an excellent choice for ocean current measurement in the Port of Paljassaare. You can learn more about it on its official website: (https://china-sonar.com/).

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