ADCP in Tanjung Emas Port: Ocean Current Measurement

1. Where is Tanjung Emas port?

Tanjung Emas port is located in Semarang, Central Java, Indonesia. It is a significant port that serves as a crucial link for both domestic and international trade in the region.

Port Scale and Throughput

The port is of considerable scale and has a substantial throughput. It deals with a wide range of cargo, from containers, bulk cargo like coal, cement, and grains, to general cargo. The annual cargo volume has increased over the years with the growth of trade activities. It is capable of berthing many vessels of different sizes, from small fishing boats to large container ships and bulk carriers.

Routes and Business

Tanjung Emas is well-linked with different domestic and international shipping routes. Nationally, the port offers transportation links to other Indonesian ports, thus helping in the shipment of goods in most parts of the Indonesian archipelago. In the international context, it is linked to other ports in Southeast Asia, East Asia, and other regions of the world. The primary business dealings include the exportation of local products such as agricultural produce like sugar and coffee, handicrafts, and manufactured goods. Most of the goods imported are machinery, chemicals, and consumer goods.

Port Management and Operation

The management of the port is geared toward effective and safe operations. Functions include vessel traffic control, handling, and storage of cargo. Advanced management systems are utilized to optimize the flow of goods and ships. High safety and security are ensured through the use of strict protocols for inspection of vessels, safety of cargo handling, and protection against unauthorized access and security threats.

Port Facilities

Modern facilities are installed in the port. The port has several berths with variable lengths and drafts to receive various vessels. There are also modern cranes and other cargo-handling equipment for the effective loading and unloading of goods. Storage facilities include vast container yards, warehouses for various types of cargo, and cold storage facilities for perishable items. Additionally, facilities providing ship repair and maintenance services are available.

Channels and Direct Routes

The channels in Tanjung Emas port are well-maintained to ensure the safe navigation of ships. These channels are regularly dredged to maintain the required depth. The port has direct routes to other major ports in Indonesia and international ports in the region. These direct routes play a vital role in facilitating trade and transportation, enabling the port to handle a high volume of cargo traffic.

2. Why should we measure the ocean currents in the Tanjung Emas port?

It is very important to measure the ocean currents in the Tanjung Emas port. First of all, for vessel safety, since there is heavy shipping traffic and current patterns must be well known for safe navigation. Uncertain currents may cause risks during the docking and undocking procedures; they may cause collisions or damage to vessels. By having accurate current measurements, port authorities can provide real - time information to ship captains, helping them to make more precise maneuvers.

The second reason is for the effective functioning of the port. Knowing the prevailing patterns helps optimize the use of the port facilities. For instance, it can help identify the most suitable locations for cargo handling and storage, considering the direction and strength of the currents. This could mean a more efficient way of loading and unloading goods, which reduces the waiting time for vessels and overall operational costs.

Additionally, present measurements are also important from an environmental point of view. They can give valuable information on the dispersion of pollutants and sediments within the port area. All this information is very helpful in maintaining a healthy marine environment, apart from serving purposes related to dredging and other coastal engineering works. It is also a more advanced and handy technique for measuring these currents as compared to traditional techniques.

3. How do ADCPs using the Doppler principle work?

ADCPs work on the principle of the Doppler effect. They send acoustic signals into the water. These signals scatter off particles in the water that are moving with the current. Due to the Doppler effect, the frequency of the reflected signal changes as the particles move.

Ship-borne ADCP

A ship-borne ADCP is installed on a vessel when it is used in the Tanjung Emas port. An ADCP flow meter sends acoustic pulses either directly downwards or side ways, depending on its orientation relative to the moving ship through the water. The signal reflected back from the water column is collected and interrogated. From the reflected signal, Doppler shifts give the water current velocity with depth. Current structure profiles in this manner can be attained during ship transit in an area.

Fixed ADCP

Fixed ADCPs can be mounted on structures such as piers or buoys. They continuously emit acoustic signals in a downward-looking direction. The reflected signals are then analyzed for the Doppler shift. Since fixed ADCPs continuously monitor the current in one location, they can provide a long-term record of the current velocity and direction, which is useful in understanding the current behavior near the port entrance or other critical areas.

4. What is required for good measurement of Tanjung Emas port currents?

For a good measurement of the current of the Tanjung Emas port, the equipment in use should be made up of reliable materials. Small-size and lightweight designs are great; this is particularly helpful to ship-borne ADCPs during their easy installation and transportation.

Low power consumption is essential, particularly for fixed ADCPs that have to operate continuously. Cost-effectiveness is also important since it allows multiple devices to be deployed for comprehensive current measurement.

The casing of ADCP profiler is preferably made of titanium alloy. Titanium alloy has excellent corrosion resistance, which is vital in the marine environment of the port. The saltwater in Tanjung Emas port can give corrosion to ordinary metals. Titanium alloy is resistant to the corrosive action of sea water, which means durability for a long time and maintains the efficiency of the equipment. It also has a high strength-to-weight ratio that helps in reducing the overall weight of the device while maintaining the structural integrity.

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

Based on Usage

Ship-borne ADCP: This is suitable for when you want to measure currents during the movement of a vessel. In the Tanjung Emas port, it can be used by ships to measure the current along their path, helping in navigation and operational decisions.

Sit-on-bottom ADCP: It is useful for long-term and fixed-point monitoring of currents near the seabed. It can be used in a port to monitor the behavior of the current at determined locations, such as near berths or around underwater structures.

Buoy-based ADCP: In case the objective of this monitoring is to carry out monitoring in a given location for a longer duration but with some flexibility in position, a buoy-based ADCP may be utilized. At Tanjung Emas port, this will lie in areas where the track of ships may not often occur but are relevant for comprehensive general patterns of currents.

Frequency-Based

For waters as deep as 70m, an ADCP flow meter with 600kHz usually suffices. For depths like 110m, 300kHz frequency is more suitable, while for very deep waters up to 1000m, a 75kHz ADCP is the better option.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, a recommended Chinese brand is China Sonar PandaADCP. It is made of all-titanium alloy material, providing excellent durability. It also offers an incredible cost-performance ratio. You can find more information about this brand on its website: (https://china-sonar.com/).

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