Bad weather has delayed the departure of Russian salvage vessels due to undertake their final expedition to raise the remains of the Kursk submarine. The 24-hour delay means they are now expected to leave the naval port of Severomorsk on Thursday. The bulk of the submarine was recovered last autumn, but the nose - which housed the torpedoes that exploded and sank the boat in August 2000 - was left on the sea bed as it was considered to be too unstable to raise. Work to lift the fragments from the Barents Sea is expected to begin on 20 May and is expected to last for at least two weeks.