Ship passage structure C1 of the St. Petersburg Dam

The St. Petersburg Dam passes through the central part of Kotlin Island, a complex of protective structures that protect the Northern capital from flooding. On the south side of the island is one of the most important elements of the dam - the C1 ship passage structure. Its width is 200 meters, and the fairway depth is 16 meters. It is here that large ocean-going vessels enter the port of St. Petersburg. On the north side of the island there is another similar structure, C2, but it is intended only for small river-sea class vessels with a draft of no more than 5.5 meters.

An underground six-lane automobile tunnel of the St. Petersburg Ring Road with a length of 1,961 meters runs under the sudoprovodny canal. The lowest point of the tunnel is located at a depth of 28 meters below the water level.

This is a giant structure-a gate that locks the passage in case of a flood threat. Two floating gates (batoports), each 125 meters long and 21.5 meters high, In the open state, the batoports are located in dry dock chambers.

When there is a threat of flooding, the dock chambers where the gates are located are filled with water, the bathoports float up and move out into the middle of the channel. After reaching the center, the shutters begin to fill with water and under their weight begin to slowly sink to the bottom of the threshold. Thus, the way is blocked for the further advance of the Baltic surge wave to St. Petersburg. It takes 45 minutes to close the shipping channel, 25 minutes to flood the flood ports on the threshold and completely block the channel.