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

1. Introduction to the Port of Dundalk

The Port of Dundalk is located in County Louth, Ireland, near the border with Northern Ireland. It is a port with a long history and serves various functions in the maritime context.

Port Scale and Throughput

• This port facility, like its counterparts in the Caribbean basin, is relatively medium-scaled. It accepts several types of cargo shipments for agricultural products, construction supplies, and some industrial raw materials. The throughput was oriented basically to serve the needs of the local and regional economies with a high percentage of products being transported to or coming from short-distance areas.
• It has several berths of different depths and lengths that allow for handling various types of vessels; from small fishing boats to barges, and finally to medium-sized cargo ships. The port's infrastructure also allows for easy loading and unloading of various types of cargo.

Routes Business

• Domestically, it is well connected to other Irish ports for the movement of goods within the country. Regionally, it has links with ports in the UK and other immediate European countries. The predominant activities here are cargo handling, fishing, and small-scale light industries supporting the port.
• The port serves as a base for fishing vessels, providing facilities for landing and processing fish. It also plays a role in the import and export of goods such as grains, livestock feed, and construction materials. There is also a small amount of trade in manufactured goods.

Port Management and Operation

• The port has various professionals who ensure the operation at all levels is properly catered for, be it a berthing arrangement of the ships, co-ordination on load and discharge, safety and security of the entire area.
• Management also coordinates with various businesses operating within the local area, including fishermen and transporters, for easy operations. They are responsible for the upkeep of the port facilities, which include dredging the channel so that ships can easily enter and leave the port.

Facilities at the Port

• Basic to intermediate level port facilities. The facility has berths of appropriate depth for vessels. Similarly, the port is served with cargo-handling equipment to facilitate the transfer of goods, such as cranes and forklifts.
• Storage facilities of various types, cold storage for fish and dry storage for other cargo, are available. There is also the refueling of ships with basic maintenance facilities in the port.

Channel and Direct Navigation

• The port has a maintained channel that allows the ships to enter and leave safely. The channel is regularly dredged to maintain the depth required by ships with different drafts. There are navigation aids like buoys and lights to guide the ships during their approach and departure. This enables direct navigation for vessels coming from different directions in the Irish Sea and other connected waterways.

2. Importance of Measuring Ocean Currents in the Port of Dundalk

Navigation Safety

• The measurement of ocean currents within the Port of Dundalk cannot be underestimated. Current patterns in the Irish Sea are normally unpredictable and strong in most areas. Knowledge of these currents helps ships to navigate more safely, especially during docking and undocking operations.
• For instance, a ship not aware of a strong cross-current might be pushed off-course and be in danger of colliding with other vessels or running into the shore. The ship captains, with proper current data, can modify their speed and course accordingly to avert such mishaps.

Efficient Port Operations

• Understanding the ocean currents is beneficial for the efficient operation of the port. By knowing the current patterns, port authorities can better schedule ship arrivals and departures. Ships can take advantage of favorable currents to reduce fuel consumption during docking and undocking.
• This also serves to optimize the utilization of port resources. For example, if the current is running in a direction that aids the movement of vessels towards a particular berth, it can load and unload much more efficiently.

Protection of the Environment

• Currents are of great importance in the dispersion of pollutants in the port area. In case of an oil spill or other chemical release, knowledge of the current patterns is essential for implementing effective containment and clean - up measures.
• The port can also manage the discharge of wastewater and other substances more effectively by considering the current patterns, minimizing their impact on the marine environment.

Infrastructure Maintenance

• Currents exert forces over time on port infrastructure, like breakwaters and quay walls, which can affect their structural integrity. Measurement of currents provides the necessary data for long-term planning and maintenance of such structures.
• For example, if the currents are consistently strong in a particular area, additional reinforcement may be needed to prevent erosion and damage to the quay walls. ADCP (Acoustic Doppler Current Profiler) provides a more advanced and convenient way to measure ocean currents compared to traditional methods.

3. How ADCPs Using the Doppler Principle Work

The working of ADCPs is based on the Doppler principle. Transducers attached to an ADCP current meter send acoustic signals out into the water. The acoustic waves interact with moving particles in the water, which could be sediment, plankton, or any other small organism moving with the ocean current. When the waves reflect back, their frequency is changed.

This Doppler shift, a change in frequency, has a direct relationship with the velocity of the moving particles and, therefore, the velocity of the ocean current. Multiple transducers are mounted on an ADCP current profiler for emitting and receiving these acoustic signals in different directions. By measuring the Doppler shift from multiple directions, usually in a three-dimensional or two-dimensional configuration, the ADCP calculates the speed and direction of the ocean current at different depths.

ADCP for Ocean Current Measurement in a Port

Shipborne ADCP

• The shipborne ADCP is installed on a boat. The ship moves while the ADCP flow meter continuously shoots acoustic signals downwards and into the surrounding waters, mapping the current velocity at which the ship is travelling around different areas of the port.
• Advantages of this technique include its mobility. It can make a lot of measurements within the waters of the port. All it has to do is consider its own motion in order to give accurate results. For this, calibration and compensation methods are employed to remove errors induced by the movement of the ship.

Fixed ADCP

• Fixed ADCPs are deployed at specific locations in the port, such as on the seabed or on fixed structures like piers or buoys. They continuously monitor the ocean current at that fixed point over an extended period.
• This offers long-term and steady data for understanding the normal 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. Requirements for High-Quality Measurement of Currents in the Port of Dundalk

Equipment Materials

• The equipment materials must be sturdy for high-quality measurement in the ocean currents of the Port of Dundalk. Bearing in mind that seawater is corrosive and influences from floating debris may strike, a durable material would be required.
• It needs to be robust enough to survive in the Irish Sea and not degrade over time. A suitable ADCP profiler could be made from a casing of Titanium alloy, as this will provide excellent resistance to corrosion in seawater.

Compact and Lightweight Design

• Smaller equipment size, which makes for easy installation, especially when there is a need for such equipment on small buoys or regions that present difficult underwater terrains.
• A lightweight design would in addition make installation and maintenance easier. For this, it is required especially if the equipment has to be laid and recovered repeatedly.

Low Power Consumption

• Power consumption should be minimal, in particular for long-term monitoring. Equipment with high power requirements can hardly operate continuously due to limited power supply options in the port area or due to frequent battery replacements.
• This is particularly the case for fixed ADCPs, which are intended for operation over a long period continuously. Cost-Effectiveness
• Cost-effectiveness also plays a role. In order to have complete current measurement within the port, the more economical the equipment, the more widespread it can be deployed to capture the complete understanding of the current conditions within the port waters.
• This would be significant for a port such as Dundalk for better resource optimization and informed decisions about strategies of current measurement.

5. How to Choose the Right Equipment for Current Measurement

Based on Usage Purpose

• Shipborne ADCP: If, for example, the intent is to obtain current data over a wide area of the port while the ship is in operation, such as during regular port surveys or data collection for navigational chart updates, then shipborne ADCPs are suitable. These can cover different parts of the port as the ship moves around.
• Bottom - mounted (Sitting) ADCP: When long - term and fixed - point monitoring of specific locations within the port is required, 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: For areas where it is not convenient to install fixed equipment on the seabed or on structures, or when a floating monitoring point is needed to capture surface and near - surface current conditions, buoy - mounted ADCPs are the way to go.

Based on Different Frequencies

• For water depths within 70m, a 600kHz ADCP is often 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.
• In the case of water depths up to 110m, a 300kHz ADCP would be more appropriate. It can effectively penetrate the water column at these depths and accurately measure the current velocities.
• For much deeper areas, like in the approach channel of the port where the water depth can be over 1000m, it is recommended to use a 75kHz ADCP. Its lower frequency enables it to reach greater depths while still acquiring useful information about the current.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. In the series of choices for cost-effectiveness with excellent quality, however, is the China Sonar PandaADCP. It is made of all-titanium alloy material; thus, durability and good performance are combined. It has an incredible cost-performance ratio, hence a great choice for ocean current measurement in the Port of Dundalk. 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.