ADCP's Application to Ocean Current Measurement in Subic Port

1. Where is Subic Port

Subic Port is located in the Subic Bay Freeport Zone, Zambales, Philippines. It is a world-class port that enjoys an enviable strategic location affording the shipping lines very easy access to the key shipping lanes in the Asia-Pacific region.

Scale and Throughput of Port

Large scale with high throughput: It is a very well-equipped port facility to handle a wide range of cargo, including containerized cargo, bulk cargo, such as coal and grains, and all types of vehicles through its Ro-Ro facilities. Its container terminal is of considerable capacity, capable of handling several thousand TEUs every year.

Subic Port is an important transshipment facility that links various regions of the world with one another. It also functions as a vital cog in the import and export activities of the Philippines, with a wide range of products passing through, from electronics and machinery to agricultural and fishery products.

Routes and Business

It is also linked with a great many shipping routes both internationally and domestically. Internationally, these would involve routes to ports in Asia, the Americas, Europe, and Oceania, while domestically it would be a central point for distribution to other Philippine ports.

It houses a very diversified set of businesses in shipping lines, freight forwarders, stevedoring companies, and logistics providers. There is a very vibrant ship-repair industry with modern facilities able to handle big vessels with large-scale repairs and maintenance. In addition, it has industrial parks and free-trade zones within its environs, thereby boosting economic activities at the port.

Subic Bay Management and Operations The port is managed by the Subic Bay Metropolitan Authority, the SBMA. They are responsible for managing vessel traffic; the berthing and mooring operations should be effective; and there should be tight security and safety measures. The SBMA is further concerned with the development and improvement of infrastructures at the port to make it competitive and abreast with international standards.

In such areas, they will co-ordinate carefully along with other authorities and various companies operating in the field and the shipping company. Based on new emerging situations, the new technological uses which are required include the proper way of handling the goods - automated container handling and better tracking and monitoring mechanism related to container handling.

Port Facilities

The Subic Port boasts of modern facilities. It has several deep-water berths capable of accommodating the largest container ships, bulk carriers, and even naval vessels. Its container terminals are fitted out with modern gantry cranes and other handling equipment that efficiently load and unload containers.

The facilities have vast areas of storage with container yards and warehouses for all kinds of cargo. These include specialized storage tanks for hazardous materials, their handling procedure, among others. Besides the above facilities, bunkering and fresh water supply and waste-disposal facilities are available. There are also dry-docks and ship-repair yards that are well equipped to handle routine vessel maintenance.

Channel and Direct Navigation

The port maintains a well-buoyed, marked channel that ensures safe navigation. The depth of the channel is dredged from time to time to maintain the requisite draft for vessels of large capacity. It has a full complement of navigational aids like buoys, beacons, and radar systems.

These aids enable mariners to navigate the channel accurately even during bad weather and tidal conditions. The port also has a well-organized traffic-control system through which entry and exit of vessels are regulated to allow direct and efficient navigation to and from various terminals and berths.

2. Importance of Measuring Ocean Currents in Subic Port

Improvement in Vessel Operations

Ocean currents in Subic Port will need to be measured to improve vessel operations. The direction and speed of the current are very necessary during precise berthing and mooring. From such knowledge, port operators are supposed to position vessels well at the time of docking and avoid collision for safety and the avoidance of damage to the vessel and port infrastructure. Besides that, favorable currents can be utilized by ships for both entry and exit in the port, which will result in huge savings in fuel and reduction of time in transiting. Given the large number of vessel traffic in Subic Port, optimizing such operations is very crucial to the general efficiency of the port.

Trade and Logistics Facilitation

Current measurements are important for efficient trade and logistics. Currents can affect shipping schedules. Shipping companies can use current data to plan their arrivals and departures more effectively, therefore ensuring timely deliveries and reduced demurrage costs. This is of essence for ports dealing with a variety of time-sensitive cargo, ranging from perishable goods to high-value electronics, where schedule optimization is very vital to ensure the smooth flow of goods and the economic viability of the supply chain.

Infrastructure Maintenance and Planning

From an infrastructure perspective, current measurements in the present provide data essential for the maintenance and long-term planning of the harbor structures. Long-term stability and durability of quay walls, piers, and other facilities depend on hydrodynamic forces caused by currents.

With proper current data, accurate designs can be made for resilient infrastructure, and preventive maintenance activities can be scheduled to extend the life of the structures and ensure their continued operation and safety.

Environmental Considerations

It is further important to measure ocean currents for purposes of environmental protection. Currents take part in the processes of dispersion of pollutants within port waters. In instances of an oil spill or some other type of contaminant, knowledge of the pattern of currents aids in establishing an effective containment and cleanup procedure.

It will also help in monitoring the influence that port activities exert on the nearby marine ecosystem in the drafting of appropriate sustainable development planning for a reduction in deleterious environmental impacts.

Compared to the traditional techniques of measurement, Acoustic Doppler Current Profiler(ADCP) is more advanced and convenient. It provides real-time and detailed information about the current profile, which allows for more accurate and efficient monitoring of the ocean currents in the port area.

3. Working Mechanism of ADCPs Based on the Doppler Principle

Working principles of ADCPs are based on the Doppler principle. ADCPs emit their acoustic signals into the water. Normally, these acoustic waves interact with moving particles in water, which may include all types of suspended sediments and small organisms. This results in a change of frequency when the acoustic waves reflected from the moving particles because of the Doppler effect.

The ADCP measures this frequency shift of the reflected signals. With particular algorithms and calibration, it will be able to obtain the velocity of the moving particles. Since the movement of these particles is mainly due to the ocean current, the ADCP calculates the velocity of the current.

ADCP in Port Ocean Current Measurement: Shipborne ADCP

Shipborne ADCPs are installed on vessels operating in the port area. While the ship is in movement, the ADCP is sending acoustic pulses in various directions, normally downwards and sideways. It continuously measures the current velocities at various depths along the track of the ship. During its motion, data gathered may be used to develop a complete map of the current field in the port area as a whole, allowing detailed insight into the pattern of currents during the voyage of the ship.

Fixed ADCP: Fixed ADCPs are deployed in selected locations within the port, such as on the seabed or fixed to fixed structures like piers or breakwaters. These ADCPs continuously monitor the ocean currents at a particular location over time. The data from fixed ADCPs is useful to comprehend the long-and consistent current conditions at key points in the Port. This data can be used as a reference for port operations, research, and infrastructure planning.

4. Requirements for High - Quality Measurement of Subic Port Currents

Equipment Requirements

Equipment used for high-quality measurement of ocean currents in Subic Port should be manufactured from reliable materials. It must withstand the harsh marine environment: the corrosive effects of seawater, high pressures at different water depths, and potential impacts from floating debris.

Other considerations would include size and weight; smaller size and lighter weight is advantageous in installations, particularly on vessels but also when space is minimal on fixed structures. This can provide greater flexibility in the sitting of the equipment.

The other important factor is that of power consumption. A low-power-consuming device is ideal, which can run for extended duration without the need to replenish batteries or too high an energy supply. This may be more critical in the case of fixed ADCPs, which may not necessarily have easy access to a constant power source.

Advantage with Titanium Alloy Casing ADCPs

The ones fitted with a casing made up of titanium alloy are some of the good ones. The good corrosion resistance of this titanium alloy means very good resistance to seawater corrosion over time, which helps in maintaining the integrity and performance of the ADCP. It has a high strength-to-weight ratio that enables a strong structure to have light weight, which is advantageous for installation and operation. Besides, the resistance of titanium alloy to high pressure at greater depths. Therefore, it is suitable to be used in different water depth conditions in the port area.

5. Guidelines to Choose the Right Equipment for Current Measurement

According to Application

• Shipborne ADCP: Where the objective is to get an overview of the current patterns in the port during vessel movements, then shipborne ADCP would be appropriate. It can cover different areas of the port as the ship sails around, giving a wide-ranging view of the current situation.
• Bottom-mounted (Sitting on the Seabed) ADCP: For long-term and continuous monitoring of the current conditions at specific fixed locations, such as near important port structures or in areas where the current characteristics are of particular interest for research or operational reference, bottom-mounted ADCPs are more appropriate. They can provide stable and consistent data over an extended period.
• Buoy-mounted ADCP: In areas where fixed installations or ship operations can hardly reach, the measurement of currents can be done by buoy-mounted ADCPs. These, while taking the readings, can drift with the currents to a certain extent and thus offer valuable information regarding changes in those areas pertaining to current.

Based on Frequency

• In general, for water depths within 70 meters, an ADCP of 600 kHz frequency would normally be quite adequate. It will deliver highly detailed and accurate current measurements that one can obtain in the relatively shallow areas of a port.
• The 300 kHz ADCP should be quite appropriate for up to 110 meters of water depth. It will penetrate this depth of the water column and deliver reliable current data.
• For deeper areas with water depths up to 1000 meters, an ADCP with a frequency of 75 kHz is recommended because it can cover such large depth ranges while still measuring the ocean currents with acceptable accuracy.

There are several well - known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, it's worth mentioning a cost - effective Chinese ADCP brand - China Sonar PandaADCP. It is made of all - titanium alloy material and offers an impressive price - performance ratio. You can visit its website at(https://china-sonar.com/) for more information.

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