ADCP in Naantali Port: Ocean Current Measurement

1. Where is Naantali Port?

Overview of Naantali Port

Naantali Port is located in southwestern Finland on the Baltic Sea. It is a fairly large and busy port. The port is well-integrated into the regional and international shipping network, serving as an important link for trade and transportation.

It handles a diverse range of cargo including containers, bulk cargo such as agricultural products and building materials, and also caters to a significant amount of passenger traffic, especially cruise ships. The port management is efficient and focuses on providing quality services and smooth operations. There are well-organized teams for vessel traffic management, cargo handling, and passenger services.

Port Facilities

Berths: Several berths have been assigned for different categories of vessels. Medium-sized container ships, bulk carriers, and cruise ships can easily lie on these berths. Such berths have modern mooring and docking facilities for safe arrival and departure of vessels. High-quality fenders and bollards resist the forces at the time of docking and undocking.

Cargo-handling Equipment: There is a variety of cargo-handling equipment along the quay. These include gantry cranes for container handling, which load and unload containers with utmost efficiency. For bulk cargo, the facilities include conveyor systems and grabs, which help in moving the materials from the ships to storage areas. In the case of cruise ships, gangways and other facilities enable smooth boarding and disembarking of passengers.

Storage Facilities: There are storage facilities for various types of cargo. For containers, there is a container yard with an organized system for storage and retrieval. For bulk materials like agricultural products and building materials, there are stockpiles with proper drainage and containment systems. There are also warehouses for other general cargo and cold - storage facilities for perishable goods.

Channel and Navigation Aids: The channel in this port is put at an ample depth and of considerable width for the safety passage of vessels. Regular dredging is performed so as to keep it sufficiently usable for vessels with differing drafts. To guide the vessel through entry and exit at the ports, navigation aid equipment like buoys, beacons, and radar systems are employed. These radar systems update the real position and movement of other vessels around the vicinity of the port.

2. Why should we measure the ocean currents in the Naantali Port?

Importance for Port Operation and Management

The measurement of ocean currents in Naantali Port is of much importance. Firstly, the safety of vessel navigation. The knowledge of the current speed and direction is vital to ship captains while approaching berths or negotiating the channel. A strong cross-current near a berth can make the process of docking quite challenging and hazardous. For instance, a ship approaching a berth against a strong current may have to adjust its speed and angle of approach to ensure smooth and safe docking. Captains can make proper decisions and avoid the chances of collisions and other accidents if accurate current measurements are provided.

The latter is very important for the optimization of the port's operation. The current data assists in more effective scheduling of ships' arrivals and departures. In the process, it helps the port authorities manage the berthing resources well, as well as to organize the loading and unloading activities by having an insight into the tidal currents and other regular flow patterns. Productivity improves because the cargo-handling operations are better coordinated.

From an environmental point of view, in the event of an accidental discharge of harmful substances like oil or chemicals, knowledge of ocean currents is useful. Considering the type of cargo handled in the port, the spread of a spill needs to be forecast. The current data can be used to quickly implement containment and mitigation measures to minimize environmental damage.

3. How do ADCPs using the Doppler principle work?

Measurement Principle

ADCPs work on the principle of the Doppler effect. When an acoustic signal is transmitted by the ADCP flow meter into the water, it scatters with the moving water particles. Since the water particles are in motion due to the ocean current, they create a frequency shift in the reflected acoustic signal received back by the ADCP meter. By the principle of the Doppler effect, this frequency shift is related to the velocity of the flow of water.

Calculation of Current Speed and Direction

The Acoustic Doppler Current Profiler (ADCP) can calculate the speed and direction of the ocean current at different depths in the water column by analyzing the magnitude and direction of this frequency shift. It can also emit signals at multiple angles and different depths to create a profile of the ocean current, showing how the current varies with depth.

ADCP Deployment in the Port

Shipborne ADCP

A shipborne ADCP is installed on ships operating in the Naantali Port area. While the ship is on the move around the port, the ADCP current meter continuously sends acoustic signals into the water underneath. The movement of the ship allows the ADCP flow meter to cover a wide area and collect current data from different locations. For instance, during a routine survey of the port by a research or inspection ship equipped with a shipborne ADCP, it can gather data on the current patterns across various parts of the port, providing a comprehensive understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs are installed at fixed locations within the port, such as on the seabed near important navigational areas or at the entrance/exit of the port. These ADCPs continuously monitor the ocean currents at their fixed positions over a long period. The data collected is useful for analyzing the regular current patterns in specific areas of the port. For example, a bottom-mounted ADCP at the port entrance can measure the currents coming in and going out to understand the tidal influences and other steady flow patterns there.

4. What's needed for high-quality measurement of Naantali port currents?

Equipment Requirements

The following are some of the important equipment characteristics that will be necessary for high - quality measurement of the currents in Naantali port. First and foremost, the material reliability is the most important one. The equipment should be able to withstand the harsh marine environment. Seawater contains salts and other chemicals that can corrode materials over time. The equipment also needs to be able to stand the pressure changes at different water depths and the mechanical forces caused by waves and currents.

The second desirable feature is a smaller size, lighter weight, and lower power consumption. The compact size allows for easier installation in various locations within the port, whether on ships, fixed structures like piers, or on the seabed. A lighter weight simplifies the installation and transportation processes. 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 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

The casing of ADCPs is preferably made from titanium alloy. This titanium alloy has excellent corrosion resistance. That means that this can keep up its structural integrity and functionality even in exposure to seawater for quite some time. Its high strength-to-weight ratio enables a durable yet relatively lightweight casing. The pressures could be higher in the deeper parts of Naantali port, and an ADCP profiler with a casing of Titanium alloy is capable of resisting such water pressures and still perform its functions of current measurement with perfection.

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

Selection Based on Usage

Shipborne ADCP: Where the interest is to carry out wide-area surveys of the port waters during vessel operations, shipborne ADCP would serve as a suitable choice. It can cover different parts of the port while a ship is moving around; thus, it gathers the largest amount of data necessary for a comprehensive understanding of overall current conditions in the whole port. This is useful in mapping the general flow patterns and variations across different areas of the port waters.

Sitting - bottom ADCP: The sitting-bottom ADCPs are better suited for long-term and fixed-point monitoring of certain locations in the port, such as near important infrastructures or areas with complex current behaviors. They can record continuously the current data at those fixed positions, enabling the derivation of local current characteristics and their changes over time.

Buoy-mounted ADCP: When it is not convenient to install fixed equipment on the seabed or on ships, buoy-mounted ADCPs can be used. They float on the water surface and can measure the currents in the upper layers of the water column. Being relatively easy to deploy, they can also be relocated if necessary, making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency

The selection of frequency for ADCPs is based on the water depth in Naantali port. For areas where the water depth is up to 70 meters, 600 kHz is usually a good choice because it will most likely provide accurate current measurements within this relatively shallow depth range. When dealing with deeper waters up to around 110 meters, an ADCP current profiler with a frequency 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 current meter 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.