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

1. Where is Gilimanuk port?

Gilimanuk port is in Bali, Indonesia. It is a strategic port, serving as an important connecting point.

Port Scale and Throughput

It handles considerable passenger and cargo traffic. It has a relatively good capacity for the handling of goods and passenger traffic. As far as throughput is concerned, it deals with considerable amounts of local produce, construction material, and supplies for the local hinterland. The port also acts as a transit point for tourists traveling to and from Bali, thereby feeding into the local tourist-related traffic.

It serves as a vital node in short sea shipping. On the domestic level, the port links Bali to the other islands in Indonesia, enabling the efficient transport of basic commodities like foodstuffs and building materials. In business matters, it handles general cargo, vehicles, and ferry operations, including passengers. This port is also engaged in trade, which includes agricultural products, handicrafts, and local goods.

Port Management and Operation

The port management is concerned with the facilitation of vessel movement and efficient handling of cargo and passengers. The operation team is responsible for berthing arrangements, ticketing for ferry services, and logistics of handling cargo. There is collaboration between the port staff, public transporters in the locality, and the relevant government agencies to ensure order and safety.

Port Facilities

Gilimanuk port has basic to intermediate-level facilities. It provides berthing facilities for ships of different types, from small fishing vessels to medium-sized cargo vessels and ferries. It has loading and unloading equipment, such as cranes and forklifts, for cargo handling. There are also waiting areas for passengers, ticket booths, and small-scale storage facilities for goods. Besides, there are vehicle loading and unloading facilities for those who travel with their cars or motorcycles.

Channel and Direct Navigation The channel within the port is kept and continuously maintained for safe passage of vessels. Besides, it has buoys and adequate signage that provide aids during the entry and exit for vessels. The channel, with a depth which allows vessel types to easily pass through, enables direct navigation according to the given signs through proper communication between ships and port control.

2. Why should we measure ocean currents in Gilimanuk's ports?

Measuring the current at the ocean floor at the Gilimanuk ports has several reasons. Basically, during practical purposes of a port, to afford a view of the regular flow helps in bringing in ships at the docks and then back again from them at higher speeds. Thus it permits timings of arrivals and departures to be closely synchronized. This can result in less fuel consumption and a reduced waiting period. For instance, a ferry can adjust its approach speed depending on the current to be able to dock smoothly.

Then again, safety is a big issue: ocean currents can affect ship stability in some areas, especially during cargo loadings and unloadings. Measured currents can help port authorities to give warnings and undertake necessary precautions to avoid various incidents, such as the drift of vessels towards other ships or structures. Besides that, current information is critical for the safety of swimmers and small watercraft within the port area.

Further, current patterns are useful for environmental management. Currents could play a part in spreading pollutants, like oil spills or sewage discharges. With correct current data, the port can prepare better contingency plans against such environmental hazards.

For the long - term planning and maintenance of port infrastructure, current measurements are crucial. The forces exerted by currents on structures like breakwaters and quay walls can cause damage over time. ADCP provides a more advanced and convenient way to measure these currents compared to traditional methods, offering detailed and real - time information.

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. As these acoustic waves interact with moving particles in the water-suspended sediment, plankton, etc., carried by the current-the frequency of the reflected waves changes. This change in frequency, known as the Doppler shift, is related to the velocity of the moving particles and, consequently, the velocity of the ocean current.

These acoustic signals are emitted and received by multiple transducers connected to the ADCP. Measuring the Doppler shift coming from different directions-usually in a three-dimensional or two-dimensional configuration-allows the ADCP flow meter to calculate the speed and direction of the ocean current at different depths.

ADCP in Port Ocean Current Measurement Shipborne ADCP

Shipborne ADCPs are mounted on vessels. In motion, an ADCP current profiler sends acoustic signals downwards and around it. It will collect the current velocity as the vessel travels across various sections of the port. The benefit is the mobility to do a wide range of measurements; however, its own motion needs to be taken into consideration for an accurate outcome.

Fixed ADCP

Fixed ADCPs are installed in fixed locations in a port on the seabed or fixed installations like piers. They are used for continuous monitoring of the ocean current at a certain point. It provides long-term and consistent data about the normal current pattern in an area. The drawback is that they can only cover the area surrounding their installation location.

4. What’s needed for high - quality measurement of Gilimanuk port currents?

For high - quality current measurement in Gilimanuk port, the equipment needs to have certain characteristics. The materials of the equipment should be reliable. Given the corrosive nature of seawater and the potential for physical damage from floating debris, a durable material is essential.

Small in size to aid in easy installation, particularly in places with minimal space available such as on smaller structures or in crowded port areas, the equipment must be. The equipment also needs to be lightweight for ease of installation and maintenance processes.

The low power consumption is essential, especially for long-term monitoring. Equipment with high power requirements may face challenges due to limited power supply options in the port area or the need for frequent battery replacements.

Cost-effectiveness is also a consideration. To obtain a proper measurement of the currents in the port, inexpensive equipment can be deployed over a larger area. The preferred casing for the ADCPs is made of a titanium alloy. This alloy has very good resistance to corrosion in seawater, which prolongs the life of the equipment. It is also robust and lightweight, withstanding high pressure while adding very little weight to the device.

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

Based on Usage Purpose

Shipborne ADCP: If the purpose is to obtain current data over a wide area of the port while the ship is in operation, shipborne ADCPs are the ones to go for. They can cover different parts of the port as the ship moves, which is useful for surveying and understanding the overall current patterns.

Bottom-Mounted (Sitting) ADCP: For a long-term and fixed point's monitoring of the particular spot, such as near key infrastructures like breakwater protection facilities and within the entrance of the channel into the port, an Bottom-Mounted ADCPs has appropriate applications. They easily provide stable data for use in understanding local current features in application.

Buoy - mounted ADCP: When fixed equipment installation on the seabed or structures is inconvenient, and monitoring needs are such that there is a floating point with coverage of surface and near-surface current conditions, buoy-mounted ADCPs should be adopted.

Based on Different Frequencies

For water depths within 70m, a 600kHz ADCP is good. It provides high-resolution current profiles in shallower areas, suitable for parts of the port with relatively shallow water, like near the shore or in small bays.

For water depths up to 110m, a 300kHz ADCP is more appropriate. It can effectively measure current velocities at these depths.

In deeper areas, where water depth can be as large as 1000m near the approach to the port, for example, the lower frequency of a 75kHz ADCP is recommended, inasmuch as its lower frequency would give greater depth with useful information of current.

There are well - known ADCP current meter brands like Teledyne RDI, Nortek, and Sontek. However, for a cost - effective option, the China Sonar PandaADCP is worth considering. It is made of all - titanium alloy material and offers an excellent cost - performance ratio. You can learn more about it at (https://china-sonar.com/).

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