ADCP in Sal Rei Port's Ocean Current Measurement

1. Location and Introduction of Sal Rei Port

Sal Rei is the primary port on the island of Boa Vista in Cape Verde. Sal Rei lies on the west coast of the island. The port is an essential maritime connection as regards the local economy and for regional trade.

Scale and Throughput of the Port

Scale: The port is relatively small to medium scale. It has a few berths, accommodating vessels of a size similar to fishing boats, local cargo ships, and a little tourism boats. The quay area is large enough to handle loading and unloading operations, has storage facilities, which should also help in the management of incoming and outgoing cargo.

Throughput: Its annual throughput covers fishing products because the fishing industry is an important economic activity in the locality. Apart from this, it takes care of the imports of consumer goods, construction materials, and fuel distributed to the local population as well as business concerns. Tourism-related traffic, such as the arrival of boats bringing in tourists, contributes to the activities in the port.

Routes and Business

Routes: Sal Rei Port is connected with regional shipping routes. This port links the country with other ports in Cape Verde, and some international shipping routes connect it with West Africa and Europe. These shipping routes have played a great role for the island's import-export activities and transportation of tourists.

Business: The main business handled at the port involves fishing activities, including landing and processing of fish harvests. This also encompasses cargo-handling services, both for general cargo and fuel. The port also serves the tourism industry, with its docking services and embarkation/disembarkation operations for tourist vessels.

Port Management and Operation

The port operates under a management system which regulates the movement of vessels in and out, berth allocation, and cargo-handling activities. The management fosters efficiency in the use of resources while observing the appropriate level of safety. They set rules concerning safety measures against the protection of ships, goods, and workers. Similarly, they care about environmental protection to lessen the impacts of the port operation on the local marine environment.

It involves protection measures such as fire and storm emergency procedures. The port also conducts checks for security purposes in regard to the safety of goods and people. Protection of the environment may, for example, be in the form of waste management and prevention of pollution.

Port Facilities

Fishing-related Facilities: Considering the importance of fishing, facilities such as fish-unloading docks, cold storage for preserving fish, and some limited areas for fish processing are available. These facilities help in handling the fishing catch and maintaining the quality of the fish products.

Cargo-handling Facilities: Cranes and equipment for loading/unloading general cargo and fuel are available. Storage areas are used for storing various types of cargo, such as construction materials and consumer goods.

Tourism-related Facilities: The port has docking facilities for tourist boats, embarkation and disembarkment areas for passengers. Basic services could include a tourist information office and small shops.

Channel and Direct Shipping

Dredging of the channels at the port to enhance smooth passage for ships. The port offers port-to-port shipping to other key ports at Cape Verde and to a few global destinations. The direct links facilitate safe and effective transportation of cargo and contribute significantly to the tourism industry.

2. Significance of Ocean Current Measurement in Sal Rei Port

Effect of the Ocean Current on the Vessel Navigation

This highly necessitates the measurement of ocean currents in Sal Rei Port for purposes of navigation. Currents, indeed, have great influence on both speed and course, especially in the case of smaller ships such as fishing boats and tourist boats. More accurate current information will enable the captains of the ships to make more accurate adjustments in their speeds and courses; hence, helping them avoid collision, dock, and undock with more ease and speed.

Influence on Cargo Handling

Currents can, therefore, affect the efficiency of the cargo-handling operations. Unstable or strong currents can make the operation of cranes and other handling equipment not as accurate as required. Measuring currents allows the port to schedule cargo-handling operations more effectively by considering the current status in order to minimize queuing of ships and maximize work efficiency.

It also refers to the measurement of ocean currents in the aspect of environmental monitoring in the port area. In the event of an oil spill or other pollutants, the current data could be useful in predicting the direction and speed with which the contaminants spread. This therefore assists the port in taking timely protective and remedial measures to protect the marine environment. ADCP current profiler is more advanced and easier to measure ocean currents than older methods; therefore, it is advantageous to Sal Rei Port.

3. How ADCPs Use the Doppler PrincipleWork

Measurement Principle

Acoustic Doppler Current Profiler (ADCP) function based on the Doppler Principle. Once an acoustic signal has been transmitted into the water by the acoustic doppler velocity meter, the signal is scattered back to the acoustic doppler flow meter by the particles and other constituents in the water. Since the Doppler effect due to water particles moving with an ocean current causes scattered signal back to the acoustic doppler velocity meter, it would arrive with a different frequency than that transmitted. By measuring such Doppler shift in frequency, thus the velocity of water particles and hence the velocity of an ocean current could be determined.

Port Ocean Current Measurement using Shipborne ADCP:

Shipborne ADCPs are installed on ships; during the movement of the ship in the Sal Rei Port area, the acoustic doppler velocity meter continuously sends and receives acoustic signals. It is capable of measuring the currents of the ocean at different depth points along the track of the ship. The data collected may be used for detailed analysis of the current state conditions of the area in which the ship is sailing. Such information would be useful for the navigation and performance of the ship.

Fixed ADCP

Fixed ADCPs would be deployed at some fixed sites in the Sal Rei Port, typically at pier ends or moored buoys. Such ADCP flow meter do not move from their locations and could operate continuously in situ measuring currents. They have the capabilities to offer current data for a long period of time and almost continuously.

4. Requirements for High - Quality Measurement of Sal Rei Port Currents

Equipment Requirements

Material Reliability: The materials used in the equipment must be highly reliable. This includes resistance to the aggressiveness of the marine environment - the corrosion by seawater, high humidity, and possible impacts from floating objects.

Small in Size, Light in Weight, and with Low Power Consumption: A small and lightweight acoustic doppler velocity meter allows for ease in installation and operation. This is especially important for shipborne ADCPs, while low power consumption allows the equipment to operate for a long time without the need for constant battery replacement or high power supplies. This aspect of the equipment design has been considered to be very important in both fixed and shipborne ADCPs.

Low Cost for Mass Measurement: In order to do large-scale current measurement in the port, the cost of the equipment should not be too high. Thus, several ADCP profiler can be distributed at different locations in the port to get wider current data.

Advantage of Using Titanium Alloy for ADCP Casing

Ti alloy is a very good material for ADCP current profiler casings. Advantages are as follows. First, excellent corrosion resistance can effectively resist the corrosive effect of seawater, ensuring long-term stability and reliability. Then, its high strength-to-weight ratio means it can provide enough strength while keeping the weight relatively low, meeting the requirements of small size and light weight. Thirdly, the thermal stability of the titanium alloy is good, helpful for normal operation in several temperature environments found in the Sal Rei Port area.

5. Selection of Current Measurement Equipment

Based on the Purpose of Use

Shipborne ADCP: Where the measurement is mainly to be carried out on ships, it will be quite suitable. It can move along with the ship and measure the currents in different areas of the port as the ship navigates.

Sitting-bottom ADCP: Sitting bottom ADCP is a great device for monitoring currents at specific points around Sal Rei Port for long-term fixed-point monitoring. Normally it will be laid on the sea floor and can continuously monitor the current around its area.

Buoy - Type ADCP: In locations where real time monitoring of currents in some area of the port is required, this type will be applicable. The buoy will be able to float on the water surface and the ADCP current profiler on it will measure the currents around it.

Selection Based on Different Frequencies

Different frequencies of ADCPs are applicable for different water depths. For example, the 600 kHz acoustic doppler velocity meter is suitable for a water depth of up to 70 m. It gives detailed current information within this relatively shallow area of water. 300 kHz acoustic doppler velocity meter would be appropriate for water depths up to 110 m, while 75 kHz acoustic doppler velocity meter is suitable for much deeper waters, reaching up to 1000 m. It will, therefore, make it possible to acquire the correct measurements of currents at different depths in Sal Rei Port according to real water depth.

There are several well - known ADCP doppler brands such as Teledyne RDI, Nortek, and Sontek. However, for those looking for cost - effective options, the Chinese brand China Sonar PandaADCP is highly recommended. It is made of all - titanium alloy material and has an incredible cost - performance ratio. You can visit its website (https://china-sonar.com/) for more information.

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