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

1. Where is Kihnu Port?

Overview of Kihnu Port

The Port of Kihnu is one of the relatively important coastal ports. It is of medium scale and is an important connection in the marine transport activity of the locality. For throughput, it handles all types of cargoes like local fishery products, agricultural produce for export, and some construction materials for import. It has a set of shipping routes that mostly encompasses regional trade, thereby connecting it with other nearby ports and fishing harbors. These routes play a very important role in the transport of merchandise that is essentially required for the local economy and livelihood.

Management and operation are focused on the local needs of the port. There are teams to handle fishing vessels, cargo ships, and the smooth flow of goods from one vessel to another. The port also co-ordinates with local customs and other regulatory bodies for policy requirements concerning trade and safety.

The port has basic but efficient facilities. It has a number of berths, which can handle vessels from small fishing boats to medium-sized cargo ships. On the quay area, there are cranes and hoisting appliances that are appropriate for the common cargos handled in the area. There are storage areas for fish and other agricultural products and goods. The port also offers vessel facilities such as fueling stations and simple workshops for maintenance.

Channel and Direct Shipping

The depth and width of the port's channel are maintained to facilitate the safe passage of vessels local to the port area. It has a size that is appropriate for the size of ships using the port. The center does not have as many direct shipping links to far-flung international destinations, but it has direct links with neighboring ports and fishing grounds. The center serves direct links, important for the local fishing and trading activities.

2. Why should we measure the ocean currents in Kihnu Port?

Significance for the Operation and Management of the Port

Measurement of ocean currents at Kihnu Port is of high importance. First of all, it concerns the safety of fishing vessels and cargo ships. Currents can significantly affect the navigation of those vessels. Accurate current measurements help captains plan their route and docking maneuvers. For example, in a busy fishing season, when many boats are coming and going, knowing the current direction and speed can prevent collisions and ensure the smooth entry and exit of boats from the port.

It also aids the port in its efficient functioning. By knowing the present pattern, the berths can be utilized to maximum efficiency and also plan out the time for loading and unloading. For example, if there is a strong tidal current that interferes with certain berths, then the working hours of those berths can be adjusted or special instructions given to ships so that the operation can be done efficiently.

Moreover, from the environmental point of view, knowing the ocean currents can help one predict the spread of any potential pollutants in case of an accident. This is especially important for a port that deals with fishing and some industrial materials. Considering these factors, an advanced and at-the-same-time convenient measurement method like Acoustic Doppler Current Profiler (ADCP) would be of great value for ocean current measurement in Kihnu Port.

3. How do ADCPs using the principle of Doppler work?

Measurement Principle

The ADCPs work on the principle of the Doppler. When an acoustic signal is emitted from the ADCP into the water, it interferes with the water particles, which are in motion due to the ocean current. The movement of the water particles produces a frequency shift in the reflected acoustic signal received back by the acoustic doppler flow meter. Accordingly, based on the Doppler effect, the magnitude of such a frequency shift would indicate the velocity of the water flow. Thus, by analyzing the frequency shift, the ADCP profiler is able to calculate the speed and direction of the water flow. The ADCP flow meter can produce a profile of the ocean current by transmitting signals at several angles and at various depths showing how the current changes with depth.

ADCP Measurement Methods of the Ocean Currents in a Port

Shipborne ADCP: A shipborne ADCP is installed onto ships serving in the Kihnu Port area. While the ship is sailing around the port, the ADCP current profiler continuously sends acoustic signals down to the water space underneath. The motion of the ship enables the acoustic doppler velocity meter to overcome large areas and obtain current measurements in various places. For instance, in the normal survey of the port, with a research or inspection ship fitted with a shipborne ADCP, it can collect data on the current patterns across different parts of the port, giving a comprehensive situation of water flow.

Fixed ADCP: These are put at fixed, stationary positions in the port, such as on the seabed near important navigational areas or at the entrance/exit of the port. They monitor the ocean currents at the same position continuously over a long period. The collected data is useful for analyzing regular current patterns in specific areas within the port. For example, a bottom-mounted ADCP at the entrance can provide an incoming and outgoing record of currents to evaluate the tidal effects and other consistent flow characteristics in the area.

4. What is needed for high-quality measurement of Kihnu Port currents?

Equipment Requirements

The equipment to be used for such high-quality measurement of currents in Kihnu Port should possess specific characteristics. First, it is material reliability. The developments should bear the severe impact of the sea, including corrosion processes with seawater. Seawater is very aggressive due to its salt concentration, and the equipment also needs to endure the changes in pressure at different water depths and the mechanical forces from waves and currents.

Also, smaller size, lighter weight, and lower power consumption are preferable. Compact size facilitates the ability to install the system in various locations at the port, whether on ships or on fixed structures like piers, or on the seabed. The lighter the weight, the easier the installation and transportation processes will be. This includes low power consumption, allowing it to operate continuously for a long duration without necessarily changing batteries or using too much power supply. This is vital in many long-term monitoring applications.

Cost is another important aspect. For one thing, lower costs allow a port to deploy more measuring devices to conduct comprehensive current monitoring across more areas of the port.

Advantage of Titanium Alloy for ADCP Casing Application

The casing of ADCPs is preferably made of titanium alloy. Generally, titanium alloy has excellent corrosion resistance, maintaining its structural integrity and functionality even in seawater for a long time. Its high strength-to-weight ratio enables the construction of a durable yet relatively lightweight casing. For instance, in those deeper parts of Kihnu Port where higher water pressures exist, an ADCP with a casing of titanium alloy will be able to resist such pressures with efficiency and continue providing current measurements quite accurately.

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

Selection Based on Usage

Shipborne ADCP: A better option would be the shipborne ADCP for wide-area surveys of the port waters when the ship is in operational mode. In this mode, the ship would be able to cover other sections of the port as it moves, collecting a vast amount of data to give a general overview of the current situation in the port area. This is useful for mapping general flow patterns and variations across different areas of the port waters.

Bottom ADCPs - sitting: For long-term and fixed-point monitoring of specific locations within the port, including places near important infrastructures or areas showing complex current behaviors, the ADCPs are more appropriate to be sitting on the bottom. They can record continuously at those fixed positions the current data, enabling the derivation of the local current characteristics and possible changes over time.

Buoy-mounted ADCP: In situations where it is not convenient to install fixed equipment on the seabed or on ships, buoy-mounted ADCPs can be used. They float on the water surface and can measure the currents in the upper layers of the water column. They are relatively easy to deploy and can be relocated if needed, making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency For the ADCPs, the choice of frequency would normally depend on the water depth in Kihnu Port. Areas with a water depth of up to 70 meters, an ADCP with a frequency of 600 kHz usually gets along since it may reach these relatively shallow depths with good current measurements. When deeper waters up to around 110 meters have to be addressed, a better option would be an ADCP with a frequency of 300 kHz. And for extremely deep sections of the port with a water depth reaching up to 1000 meters, an ADCP with a frequency of 75 kHz is recommended to ensure reliable profiling of the ocean currents at such great depth.

Well-known ADCP brands include Teledyne RDI, Nortek, and Sontek. However, there is another excellent Chinese brand, China Sonar PandaADCP. It is made completely of titanium alloy material, which contributes to its good durability in the oceanic environment and possesses an excellent value-to-price ratio. You can contact them on their website: .

China Sonar Panda ADCP - Made completely of titanium alloy material that contributes to its good durability in the oceanic environment and possesses an excellent value-to-price ratio. You can contact them at:(https://china-sonar.com/).

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