70 years missing. The submarine "S-9". During the Second World War to support the German war machine was strategically important transport in the Baltic Sea, the supply of ore mined in the mines in Sweden, Germany, and food and troops from Germany to Finland. Disruption of freight transport and that the supply of ore seriously complicated the work of the German war industry and the effects of the German army. Due to the fact that the dominance in the Baltic sea and in the air belonged to the enemy, Soviet ships were locked in Kronstadt. The main danger in the Baltic Sea for the German transport ships were submarines. The Germans have made every effort to block Soviet submarines in the upper part of the Gulf, thus ensuring the safety of his vehicle convoys. In the spring of 1942 in a fairly short period of time the Germans have created two powerful anti-mine and artillery positions: Hogland and Nargen-Porkkalla-Uddskuyu. Each of these items consisted of a series of minefields, which are located across the possible ways of deployment of Soviet submarines. The length of them along the front envisaged such as to either the right or left to avoid them was impossible. Between the rocky areas Porkkalla Udd and the island Nargen (Naysar) parallel to the Helsinki - Tallinn was equipped minefield "Nazhorn" ("Rhino"). The second minefield was found on the 27th meridian east longitude. It was called the fence "Zeigl" ("Sea Urchin"). In addition to these two barriers were installed and the third - between the islands and Lavensaari KOTLINA called "Tiger". Next to it - the fourth titled "Urs". Fifth, quite a powerful barrage of lies to the south of the island and Lavensaari called "Zyehund" ("Seal"), a total of 1942 to the summer in the Gulf was put 21 thousand minutes. Bottom influence mines were placed in a line at intervals of 40-60 m and at depths greater than 50 m in order to prevent slippage of submarines at the bottom. A particular danger for our submarines were anti networking boom. At the narrowest point the Gulf of Finland (on Nargen-Porkkallo Uddskoy-position) with a compound of the Germans net defenses set up two lines of powerful anti-submarine nets, which are separated from each other by 70-100 m, these networks have been very strong, as were made of steel wire with a diameter of 18 mm. To the bottom of the Gulf of heavy network fastened anchors, while floating upright held on numerous floats. The deepening of networks from the surface of the water reaches 40-70 m, almost overlapping in the area the whole range of possible submarine depth control. However, where the depth of boats allowed to slip under the net, have been put bottom mines. The new anti-submarine barrier, consisting of mines and anti-submarine nets, called "Valros." On the wings of his were set underwater sonar. Along the network of anti-ship cruised mobile patrols. Only in the western part of the Gulf of Finland was concentrated 240 different anti-submarine ships and boats, ready at any moment to rush toward the detected boat. Nowhere and never submarines were performed in the most severe conditions such as in the Soviet Baltic during World War II. In his last campaign for the exploration Nargen-Porkkala Udsky abroad "C-9" was published July 30, 1943. After going unnoticed, all minefields, August 7-9, surveyed the anti-submarine network and reported the situation. Trying to force the network boom ended in failure. Trying to break through, "C-9", released in the direction of the torpedo nets, but was spotted and attacked by the forces of the PLO. On the night of August 12, the submarine reported on his return, and asked for the time and place of the meeting with an escort. More "C-9" not communicate.