Rafting needs to understand the flow pattern

During the exciting rafting process, the experienced paddlers always look closely at the river for every corner of the river or in front of the rapids. In the area of ​​rapids, there are many waves and many reefs. The purpose is to find out those Hidden traps and find the best way to cross the rapids. To find out how the rapids are formed and what are the risks to the boat, we must first understand the basic forms of the current.

Risky Beach Tongue

- When the river bed is tilted downwards, white waves appear on the calm water, and the torrent is usually the fastest in the central part of the bed. In areas where the two sides of the strait are sloping and slightly shallow, the river is obstructed and the flow rate is reduced, thus creating a phenomenon in which the middle water flow is faster. In addition, the faster flow of water at the center has a greater force, which further flushes the sand and sediment, removes resistance and obstacles, and forms a "V" shaped tongue. The top of the "V" character usually points to the minimum resistance minimum resistance. aisle.

Rolling waves

- Reefs that completely exposed the water surface are easy to find, but some reefs hidden under water have hidden mysteries. When water flows over the top of the reef, it enters the turbulent flow (water stoppage) behind the reef. The river forms a reverse flow (flows upstream). This phenomenon is called rewinding and appears downstream of the semi-hidden reef. When the reef is just below the surface of the water, it is difficult to see from the upstream direction because it cannot see the water. Pay attention to the calmer part of the torrent, as the underwater reef diverts the turbulent flow, and the water is not parallel to the waves when it flows over the surface of the reef. If you go ashore and look at it, you can look at the direction from the downstream, when the rolling wave is very obvious. Some reefs are covered by desolation waves and must be continuously observed with full attention before they can be seen. If a larger, deeper reef is to be buried, there will be a larger rewind in the downstream, usually called a “hole.” Such “holes” are often very powerful and can easily be overturned. The "hole" resembles a flush toilet, and once it strays into it, it seems to be attracted by gravity and rotates like a gyroscope, which is trapped in it for a long time. Therefore, spare no effort to avoid it.

Standing waves

-- River water flows faster in steeply descending riverbeds and slower in slower riverbeds. When a fast-flowing water stream encounters a slow-flowing stream, and the water flow cannot be drained in time, the waves will pile up and form a high standing wave. The size of standing waves is related to the amount of water and the drop. Normal standing waves do not cause problems. If the standing wave is high but the slope is gentle, the best way is to point the boat at the tip and ride directly. This kind of wave is powerful and it is very enjoyable to walk through the stormy waves. If the standing wave looks very steep, it is very likely that it will overturn. Should choose to pass from the edge of the wave. Because the edge part tends to have a gentler angle and a lower height. But first, it should be confirmed whether it is a standing wave or an underwater reef. Underwater reefs also ignite waves as they rush through. Only the rocks provoked waves and the standing waves seemed very regular.

Turn

- Usually, the deepest and fastest water flow is in the outer lane of the turn. The trend of the river is to push the boat to the turning lane, where reefs and other dangerous conditions are more common. It is generally required to adjust the boat at a forty-five degree angle during cornering and keep it in the lane. Once necessary, harnessing the power of river water can make it easier to navigate outside. However, if you want to draw in from the outside, it is very difficult to overcome the full resistance of the river.

Surabaya

- Behind the reef or behind the prominent parts of the two banks, the flow of the river is opposite to the mainstream and flows upstream. This is called drowning. The turbulent flow at the turn of a river is also referred to as drowning, although the water here does not flow in the upstream direction. There is a waterline at the intersection of the main stream and the muddy water. This hurricane is very overbearing. Inexperienced novices can't see it. If they don't use the power of the two streams, they may be trapped for hours and they won't be able to get out. In addition, special attention should be paid to the fact that there are two different streams of water fighting at the waterline, and a strong waterline is encountered. In case of carelessness, the ship will be "flattened". Drowning water is very useful for boat trips. You can use drowning to stop ashore, reconnaissance rapids, establishing rescue points, waiting for backward companions, etc., but those rotating turbulent drownings should be avoided.

There are also no obvious signs on reefs and waves, eddy currents, and trapped shoals made up of "holes." The paddlers can only draw an imaginary passage through the rapids in the rapids and try to cross the danger zone along this passage. In addition, the rapids are different from the shore when viewed from the water level. Therefore, experienced paddlers have established alternatives before they are adopted so that they do not become confused when they cannot enter the original route.