river, part of the river with a relatively large drop in the water level and high velocity. Formed, as a rule, at the intersection of the river rocky ridges, outputs trudnorazmyvaemyh rocks, clusters of boulders, debris, rocks, etc. Simple P, already found in the water routes 2 — 3 COP. The characteristic elements of PA are weirs to-rye, depending on the angle of incidence of water — more than 45'', ca. 45'' or less 45'' — classified acc. at the falls, and just plum vodoskaty
— Usually the most free from stones, and therefore most passable place in P. Most drains forms a triangle formed by the line of inflection of the water flow and oblique jets from rocks, limiting drain at the base. Converging spit "jets cause the appearance of standing waves (see Wave standing) or a chain of waves for a corner. The party can be one sink the entire width of the river or several scroll drains diff. height and power, separated by protruding rocks or stones. If the AP has several. consecutive discharges, the distance between which is not preexceeds the length of the vessel is called a P. single-stage, and if between plums vessel can maneuver freely and go from one bank to another, Dest. multistage, distinguished plum straight and oblique: at direct discharge crest line of the water flow is perpendicular to the river, with a skew — forms an acute angle over the river. Narrow oblique drain, in a rum-depth channel in the line of inflection is very different in different banks, called. woven or screw.
In determining the possibility of passing P. consider features plum, seaworthiness of the ship and crew readiness. The easiest to pass round. ships — P. direct discharge, the most difficult and dangerous — with woven drain. Single flat straight plums vodoskaty passable for tour. all types of vessels. On small rivers are recommended to keep Wed line of the triangle formed by converging streams flow, since there is usually more depth and direction cleaner. On large rivers should avoid going over the top of the triangle drain, ie, here the greatest danger for the vessel to be reversed steep standing waves. If the preliminary step. AP examination (and such inspection is required, especially for those who are first time this route), there is uncertainty in the success of its passage, we must twine Court (see twine) or carry them along the shore.
Lit.: Travelling on the rowing boats, M., 1979.