The 4,400-dwt Siderfly (built 1985) suffered two gashes of three by five metres in its hull in the clash with the 6,080-cbm Coral Ivory (built 2000) at 3am in the southern part of the waterway near Kudensee.

The vessel was listing at 45 degrees and was taking on water, the German coast guard said.

Two tugs are on hand to try to stabilise the ship, which a radio report said earlier was sinking.

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