Application of ADCP to Ocean Current Measurement in Port of Hamina

1. Where is Hamina Port?

Introduction of Hamina Port

Hamina Port is located in Finland, on the Gulf of Finland. It is a large-scale and major port with significant scale and throughput. The port is well-integrated into the Baltic Sea shipping network and forms an important link in the regional trade. The cargo portfolio handled includes containers, bulk cargo, particularly forest products like timber and pulp, and a wide range of industrial goods.

The management is effective, focusing on operational optimization for the smooth processing of goods and vessels in traffic flow. There are teams operating for different functions, vessel traffic management, cargo handling, and security. Advanced technologies have been adopted to ensure safety and boost productivity.

Facilities

Berths: The port has several berths, which are designed to handle various vessels. There are berths for container ships and bulk carriers. These berths have modern mooring and docking facilities to ensure the safe arrival and departure of ships. Strong bollards and fenders are used to withstand the forces during docking and undocking.

Cargo-handling Equipment: There are gantry cranes for container handling, which can load and unload containers with great efficiency. For bulk cargo, there is a conveyor system and handling equipment suited for forestry and other bulk products. The equipment is designed to move cargo quickly from the ships to the storage areas or vice-versa.

Storage Facilities: There are extensive storage areas for different types of cargo. For containers, there are organized container yards. For bulk materials like timber and pulp, there are storage areas with proper protection from the elements and systems to manage the flow of goods. The port also has provisions for other general cargo storage.

Channel and Navigation Aids: It maintains the depth and width of the port's channel to a suitable extent in which ships can comfortably pass. Such works in the channel are done occasionally by dredging to allow vessels with different drafts to navigate through it. It has navigation aids like buoys, beacons, and radar systems for directing ships into and out of the port. The radar systems provide real-time information on the position and movement of other vessels within the area.

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

Importance for the Operation and Management of Ports

The need to measure ocean currents in Hamina Port is for several critical reasons. Firstly, measuring the currents is vital in so far as vessel navigation is concerned. Ship captains require the speed and direction of the ocean currents when approaching berths or navigating through the channel. A strong cross - current near a berth can make the process of docking hazardous and difficult. For example, a ship approaching a berth against a significant current has to adjust speed and the angle of approach to enable smooth and safe docking. Accurate current measurements enable captains to make better decisions and reduce the risk of collisions and accidents.

It is also crucial for the optimization of the port's operations, current data provides an accurate basis for the scheduling of the arrival and departure of ships. By understanding the tidal currents and other regular flow patterns, the port authorities are able to better allocate the berthing resources and plan loading and unloading activities. Increased productivity is attained because now cargo-handling operations can be coordinated more efficiently.

From an environmental perspective, during an accidental discharge of oils or chemicals from ships and port facilities, the use of ocean currents is very helpful. With the current data available in predicting the spread of spills, a quicker response will ensure containment and mitigation to decrease the 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 meter into the water, the moving water particles scatter the signal. Since the water particles are in motion due to the ocean current, they cause a frequency shift in the reflected acoustic signal received back by the ADCP profiler. According to the Doppler effect, this frequency shift is related to the velocity of the water flow.

Calculation of Current Speed and Direction

By analyzing the magnitude and direction of this frequency shift, the ADCP current meter is able to calculate the speed and direction of the ocean current at discrete points in the water column. By transmitting signals along multiple directions and at a variety of depths, a profile of the ocean current can be obtained, outlining how the current changes with depth.

ADCP Deployment in the Port

Shipborne ADCP

An Acoustic Doppler Current Profiler (ADCP) has been installed on ships that operate in the Hamina Port area. The ADCP current profiler, while the ship moves around in the port area, continuously emits acoustic signals into the water below. The movement of the ship enables the ADCP flow meter to cover a huge area and collect current data from different locations. For instance, in a normal survey of the port by a research or inspection ship with a shipborne ADCP, it can collect data on the current patterns across various parts of the port for a complete understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs are located at fixed positions in the port, such as on the seabed near major areas of navigation or at the entrance/exit of the port. These ADCPs continuously record ocean currents at their fixed position over a long period of time. The collected data is useful for studying regular current patterns in certain areas of the port. For example, a bottom-mounted ADCP at some distance off the entrance may continuously record the incoming and outgoing currents while giving an indication of the tidal effects as well as the other regular flow features there.

4. What is required for a high-quality measurement of currents in the Hamina port?

Equipment Requirements

For high-quality measurement of the currents in Hamina port, some equipment characteristics are very important. The first one is material reliability. The equipment has to resist the aggressive marine environment. Seawater contains salts and other chemicals that can destroy the materials after some time. It also has to bear pressure changes at different depths and mechanical forces caused by waves and currents.

Second, the desirable properties are smaller size, less weight, and low power consumption. Smaller size provides easy installation at various locations in the port, whether on ships, on fixed structures such as piers, or even on the seabed. Less weight reduces difficulties with regard to the processes of installation and transportation. The low power consumption means that the equipment can run for very long hours without changing batteries frequently or having a huge supply of power, especially for applications requiring long-term monitoring.

Cost is another major factor. The lower the cost, the more devices the port authority can install for current monitoring at different points of the port.

The Advantage of Titanium Alloy for ADCP Casing

The casing of ADCPs is preferably made of a titanium alloy. Titanium alloy has superior corrosion resistance, which means that even after a long exposure to seawater, the structural integrity and functionality of the material can be preserved. Its high strength - to - weight ratio enables one to build a casing that is strong enough to be durable yet relatively lightweight. For instance, in deeper parts of the Hamina port with higher water pressures, an ADCP profiler with a casing made of titanium alloy can effectively withstand such pressures and still deliver correct current measurements.

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

Selection Based on Usage

Shipborne ADCP: In cases where wide-area surveys of the port waters are needed with the ship in operation, shipborne ADCP will be applicable. It will be able to cover the various sections of the port as the ship moves around, gathering substantial data that can provide an overview of the overall current situation in the port. That would be useful in mapping the general flow patterns and their variation in the different areas of the port waters.

Sitting - bottom ADCP: It is more appropriate for monitoring specific locations in the port at long term and fixed point, especially the ones near important infrastructures or areas with complex behaviors of current. They will be able to continuously record the current data at fixed positions, which can help in providing insights into local current characteristics and their possible variation over time.

Buoy-mounted ADCP: In cases where 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. They are relatively easy to deploy and can be relocated if needed, making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency

A rule of thumb for frequency in selecting ADCPs for current profiling depends on the depth at Hamina port. For such an area where the water does not go beyond 70 m deep, an ADCP operating with a 600 kHz frequency is an advisable device, as a correct measure can be assured over such relatively shallow water depths. For deeper waters of up to approximately 110 meters, the use of an ADCP with a frequency of 300 kHz is more advisable. And in very deep sections of the port, with water depths up to 1000 meters, an ADCP current profiler operating at a frequency of 75 kHz should be recommended for reliable profiling of ocean currents at such large depth.

There are several well - known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCPbrand-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.