Application of ADCP to Ocean Current Measurement in Algeciras Port

1. Where is Algeciras Port?

Algeciras Port is located in the south of Spain and belongs to the autonomous community of Andalusia. It's a strategic port which falls within the Strait of Gibraltar area.

Port Scale and Throughput

Algeciras is among the largest ports in Europe and one of the most important global shipping centers. It boasts an extensive port area and long quay lengths. The facility is very impressive, with high tonnage, containers, crude oil, LNG, and other bulk cargo throughput. For example, it is an important hub in trans-shipment, where goods from different shipping routes are transferred at its container terminal, which is capable of processing a large number of TEUs annually. - Its location at the entrance of the Mediterranean Sea makes it a crucial link in the chain of world trade, connecting Europe, Africa, and the Americas.

Routes and Business

The port is connected to most international shipping lanes. A major trans - shipment hub, this is a point where the goods are moved from one vessel to another for further distribution. The ranges of business areas are from shipping services, freight forwarding, and logistics operations. It is significantly present in the container shipping market, as most of the shipping lines have the port as a call point.

The port also plays a major role in the energy sector by hosting the facilities that handle the importation and export of oil and gas.

Port Management and Operation

The port is managed through well-structured administration. Infrastructural development, maintenance, and all other works are dealt with by the Port Authority of Algeciras. It coordinates with various private bodies like terminal operators, shipping companies, and service providers for the smooth functioning of the port.

Operational works involve complicated processes such as vessel traffic management, cargo handling, and customs procedures.

Port Facilities

Algeciras Port is a modern port facility with very efficient facilities. It has modern container terminals that boast the latest type of gantry cranes and can handle even the largest container ships. The liquid and dry bulk cargos are handled by specialized terminals complete with storage tanks and silos.

The port has all kinds of logistic services in its premises, starting from warehousing to cold storage for perishable goods, container repair, and maintenance facilities.

Channels and Direct Navigation

It has well-maintained channels, dredged to the depth required to take vessels of large scale. A position in the Strait of Gibraltar enables vessels to head directly for other key ports in the Mediterranean, the Atlantic Ocean, and along the African coast. All this direct access adds to its importance as both a transit and trading port.

2. Why will the ocean currents at the Algeciras port be measured?

Safety of Navigation

The knowledge of ocean currents is important for safe navigation. Within the busy waters of Algeciras Port, strong currents in the Strait of Gibraltar are able to significantly affect a vessel's course and speed. The accurate measurement of the currents will enable ship captains and pilots to better plan their approach and departure from the port, hence reducing the risks of collisions and grounding.

Currents can also affect the manoeuvrability of vessels but far more so large tankers and container ships. For such critical stages as berthing and un-berthing, correct current information may form a basis for all necessary readjustments of the ship's navigation.

Port Operations and Efficiency

Another critical use of the current patterns is port operations. The flow of the currents can affect the process in the light of docking ships. In a given current, if not considered, it can lead to an on-target alignment between the ship and berth, which can damage either the ship or the port infrastructure. In addition, currents take into account the movement of tugs as well as other support vessels in the area of the port. Measurement of the currents allows for better scheduling of such operations, thus improving overall productivity of the port. This is a more advanced and convenient method of measurement of currents, unlike traditional ways. Real-time data is acquired with an advanced method to allow for good decision-making.

3. How do ADCPs using the Doppler principle work?

Acoustic Doppler Current Profiler(ADCP) basically work on the principle of the Doppler effect. They emit acoustic pulses into the water column. Due to the interaction with particles or other objects which are moving with the current, the frequency of the reflected sound waves changes.

Ship-borne ADCP

A ship-borne ADCP is normally mounted on the hull of a vessel. While the ship is in motion in the water, the ADCP measures the relative velocity of the current with respect to the ship's motion. It continuously records the frequency shift caused by the Doppler effect on the reflected acoustic signals. Then, signal-processing algorithms make an estimate of the relative velocity of the current. It will calculate the absolute current velocity in that area, considering the vessel's own speed obtained via other navigation systems.

Fixed ADCP

Fixed ADCPs are installed in pre-determined fixed positions in the port area on the seabed or on a pier. They continuously send acoustic pulses into the water and detect the frequency shift of the reflections. They can only provide the stationary view of the current velocity at a point. This will be useful for long-term monitoring of the current patterns, such as in understanding how the currents vary with tidal cycles or seasons.

4. What's needed for high-quality measurement of Algeciras port currents?

Equipment Characteristics

The equipment should be prepared with reliable materials for high-quality current measurement in Algeciras Port. Since it is a marine environment, it needs to be able to resist the corrosion of saltwater and other harsh conditions. A smaller size and lighter weight are advantageous in making it easier to install and take care of, especially on sites like buoys or confined spaces on ships.

Low power consumption is essential, especially in long-term deployments with minimal accessibility to the sources of power. Cost-effectiveness is also an important aspect, as this would allow more usages of equipment for comprehensive current measurement across the port.

Advantages of Titanium Alloy Casing

The casing of ADCPs is preferably in the alloy of titanium. The excellent corrosion-resistant properties of the titanium alloy have a very special importance in a port like Algeciras. Because the salinity of seawater and other corrosive agents is high, equipment manufactured with less resistant materials would be deteriorated within a very short time. Being strong, long-lasting, and resistant to the pressure of water and all kinds of potential mechanical impacts, the alloy also has excellent corrosion-resistance properties in a place like Algeciras.

5. Selection of Equipment for Measurement of Current

Depending on Type of Installation

Ship - borne ADCP: It will suit the vessels, which are in need of measurement during their transit to and around the port. In providing current data, this method has proved quite mobile for ships that always have to be on the move, such as container vessels and tankers.

Sitting-bottom ADCP: It can monitor the current at one point, in a fixed way, as the entrance of a channel or near a berth. In this way, it offers a continuous and stable measurement of the current at the same point.

Buoy-type ADCP: If floating platforms are appropriate, especially when conducting measurements in open water areas within the port or in areas where the bounds of the area to be measured are not well defined. The buoy-type ADCP serves to monitor the broader areas and usually can provide essential data regarding the general patterns of currents across the whole port.

Frequency-Based

In water depths up to 70m, one would normally use a 600kHz ADCP. This higher frequency allows for better resolution for the measurement of shallower currents.

For depths around 110m, a 300kHz ADCP is more appropriate. It offers a balance between depth penetration and resolution.

In the deeper waters, up to 1000m, the ADCP frequency would be 75kHz. This would be lower to allow it to penetrate deeper in the water column over greater depths.

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

Here is a table with some well known Acoustic Doppler Current Profiler(ADCP) instrument brands and models.