ADCP in Merak Port: Ocean Current Measurement

1. Where is Merak port?

Merak port is in the western part of Java Island, Indonesia. It is a strategic port that serves as an important connecting point between Java and Sumatra, as well as other regions.

Port Scale and Throughput

Merak port has a relatively big scale and a big throughput. It handles different types of cargo, including containers, bulk cargo of coal and cement, and general cargo. The annual cargo volume is very big, with a trend of growth due to increased trade activities. It has the capacity to berth a large number of vessels-from small local ships to big ocean-going vessels.

Routes and Business

It is well-connected to the major domestic and international shipment routes. Domestically, it serves as one of the important links that carry goods between different islands of Indonesia. Internationally, it has connected its ports with those from Southeast Asia and beyond. Its main business activities involved a wide range of imports and exports. Exports ranged from agricultural products to manufactured goods and natural resources, while imports included machinery, equipment, and consumer goods.

Port Management and Operation

The port management primarily works for efficient and safe operations. The vessel's traffic control, cargo handling, and storage come under the observation of the Port Authority. Advanced port management systems are implemented to regulate the flow of goods as well as ships. Moreover, safety and security concern tops the priority list. They have strict regulations in vessel inspections and hazardous material handling.

Port Facilities

The Merak port is a well-facilitated port having a number of berths with different characteristics that could fit various vessel sizes and types. In addition, modern cranes and other facilities for cargo handling have been provided for efficient loading and unloading of goods. It has vast areas of storage that include warehouses for various types of cargo and cold storage for perishable items. Besides these, the facility also provides ship repair and maintenance facilities, including dry docks.

Channels and Direct Routes

The channels in the port are maintained so that the ships can have safe navigation. These are regularly dredged to attain the depth required. The Merak port has direct routes to other major ports in Indonesia, such as the port of Tanjung Priok, and other international ports in neighboring countries. These direct routes are crucial in facilitating trade and transportation.

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

Measuring ocean currents in the Merak port is quite important for several reasons. First of all, this will provide safety to vessels. Due to the huge volume of shipping traffic, accurate knowledge about current patterns is of vital importance for safe navigation. Unpredictable currents may cause difficulties in the docking and undocking procedures and can result in collisions or vessel damage. By measuring the currents, the port authorities can give in real time information to the captains of ships to make the relevant adjustments in maneuvers.

Secondly, for the efficient operation of the port. Understanding the current patterns helps in optimizing the use of port facilities. For example, it can assist in determining the best locations for cargo handling and storage based on the direction and strength of the currents. This can lead to more efficient loading and unloading of goods, reducing waiting times for vessels and overall operational costs.

In addition, in terms of environmental protection and coastal management, present-day measurements can also be of great help. They are able to deliver information about the dissemination of pollutants and sediments around the port area. This, again, is very crucial in maintaining a healthy marine environment and planning dredging and other coastal engineering projects. The Acoustic Doppler Current Profiler (ADCP) allows for an advanced, much more convenient measurement of those currents compared to traditional techniques.

3. How do ADCPs using the Doppler principle work?

ADCPs work on the basis of the Doppler effect. They send acoustic signals into the water. These signals interact with particles in the water that are moving with the current. As these particles move, the frequency of the reflected signal changes owing to the Doppler effect.

Ship-borne ADCP

When a ship-borne ADCP is used in the Merak port, it is installed on a vessel. As the ship moves through the water, the ADCP current meter sends out acoustic pulses either in a downward-looking or side-looking direction. Reflected signals from the water column are received and analyzed. The Doppler shift in these signals is used to calculate the velocity of the water current at different depths. This allows for the profiling of the current structure as the ship travels through the 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 analyzed for the Doppler shift. In this way, fixed ADCPs, by continuously monitoring the current in a particular place, can provide a long-term record of current velocity and direction, which may become very useful in understanding current behavior near the entrance to a port or at some other critical area.

4. What is required for high-quality measurement of the currents at Merak port?

For high-quality current measurement in the Merak port, the equipment must be made from reliable materials. A compact size and lightweight is advantageous to the ship - borne ADCPs, as this will provide ease of installation and transportation.

For a fixedly deployed ADCP profiler, operating continuously, the power consumption should be low. Also, cost-effectiveness ensures that a number of ADCPs can be deployed with redundancy for accurate current measurement.

ADCP meter casing material is titanium alloy. It has a superior property for corrosion resistance in the seawater environment at the port area. The saltwater in the Merak port is corrosive to ordinary metals. Titanium alloy is resistant to seawater corrosion and hence will make sure that the equipment lasts long. It also has a high strength-to-weight ratio, which helps in reducing the overall weight of the device while maintaining its structural integrity.

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

Based on Usage

Ship-borne ADCP: This is ideal when one wishes to make measurements of currents during vessel transit. At the Merak port, this equipment may be fitted on vessels and used to measure current alongside their course to enable ships to better navigate the ports and support operational decisions.

Sitting-on-the-bottom ADCP: Most suitable for long-term fixed-point monitoring of near-bed currents. In the case of a port, these can be used to monitor the current behavior at specific locations such as near the berths or around underwater structures.

Buoy-based ADCP: When the purpose is to monitor the current in a particular area over a longer period and when having some flexibility in location, a buoy-based ADCP can be used. This could be placed at all places in Merak Port where ships may not necessarily pass frequently but are essential in the understanding of overall patterns of current.

Based on Frequency

An ADCP current meter frequency of 600kHz will normally suffice for waters as deep as 70m, while 300kHz is more suitable for depths of around 110m, and a 75kHz ADCP is the better option for very deep waters up to 1000m.

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.