The next morning "Kursk" was preparing to fire a practice torpedo at the "Pyotr Velikiy". A hydrogen peroxide leak in the torpedo caused it to explode while in the forward torpedo compartment, starting a fire and destroying two compartments. The ship sank to the seabed where within a few minutes the fire caused the remaining torpedoes to detonate. This destroyed much if the front part of the "Kursk", killing most of the 118 crew members. The nuclear generators shut down safely. Some 23 survivors gathered from the aft compartments into the last, ninth compartment of the submarine to await rescue. Some hours after the explosion, concerned at the "Kursk"s failure to report in, Popov ordered Motsak to alert the fleet's rescue forces. Six hours after the "Kursk"s sinking, Motsak ordered the fleet's rescue vessel, the "Mikhail Rudnitsky" to come to one-hour readiness to put to sea. An hour later Motsak ordered five Ilyushin Il-38s to begin searching the exercise area, subsequently supplementing the effort with six helicopters. It is believed that most of the crew died within 6 hours of the explosions, before the sub was even identified as missing. Motsak was due to give a press conference on 15 August, four days after the "Kursk" sank. He was replaced at the last minute by Igor Baranov, of the Rubin Design Bureau, which had designed "Kursk". It was not until 20 August that Motsak admitted that the Russian Navy had no deep sea, saturation divers, using this as justification to accept aid from foreign navies. On 21 August divers were finally accessed the submarine and opened the aft escape hatch. They confirmed that there were no survivors from the 118 men who had been aboard. Motsak announced the news. "Our worst expectations are confirmed. All sections of the submarine are totally flooded and not a single member of the crew remains alive." Motsak was one of a number of officers who suggested that a foreign submarine had collided with the "Kursk" and caused the disaster. During the recovery of bodies, a note written by Dmitry Kolesnikov, the senior ranking survivor of the initial explosions, was found. In a televised announcement from fleet headquarters at Severomorsk, Motsak announced the recovery of the first bodies from the wreck, and a summary of the contents of the note. Motsak oversaw the salvage operation to raise the wreck of the "Kursk" between July and October 2001, with the "Udaloy"-class destroyer as his flagship.