TURKU, Finland -- The bow door of the car ferry Estonia was torn off allowing water to flood in and sink the ship, killing 910 people, video film of the wreckage revealed Monday. The film, released at a news conference in this Finnish port where a three-nation board of inquiry was meeting, showed the bow door, or visor -- which is meant to swing up into the air in port -- was missing.


The investigators, from Estonia, Finland and Sweden, said a locking device on the moveable outer bow door had failed. "The bow visor has become detached from the vessel as a result of the failure of the bow-visor locking devices," the board said in a statement.


Some 910 people died in the catastrophe last Wednesday when the 14-year-old ship, sailing from the Estonian capital of Tallinn to Stockholm, sank off the southwest coast of Finland in heavy seas.


Some 137 people survived, about 100 bodies have been recovered but around 810 people perished and are entombed in the ship's wreckage.


The board of enquiry, confirming reports that the bow door was responsible for the sinking, said the visor had not yet been located. The ship is lying in 80 meters of water.


"The water-tight bow ramp that was located behind the visor is still in place, although there is a gap of about one meter along its top edge, which has allowed water to flow onto the car deck," the board said.


The footage was taken by remote-controlled underwater vehicles equipped with cameras. The film showed the words "Estonia Tallinn" on the side of the ferry before zooming in on a hole in the bow of the ship where the bow visor should have been.


Computer analysts have said that just 35 centimeters of water on the ferry's cavernous car deck would be enough to start major rolling which would be virtually impossible for a ship's captain to correct.


In response to speculation that the bow doors were responsible for the disaster, a replacement vessel for the Estonia will have its bow door permanently sealed, the owners said Monday preempting the accident investigators' conclusions.


The Estline shipping company said the Vironia -- sister ship to the Estonia -- would have its bow doors sealed.


The decision had been taken "against the background of the catastrophe with the Estonia and earlier incidents with the bow doors on Swedish and Finnish-flagged Baltic Sea ferries, which have now come to light," Estline said in a statement.


The Vironia, due to begin sailing next month on the same Tallinn to Stockholm route plied by the Estonia until it sank last Wednesday, will no longer be able to load and unload vehicles through its bow doors.


Cars and trucks will now drive on and off through the rear section of the ship, turning around in the cavernous car deck of the ferry. This makes the loading and unloading process longer and means ferries can make fewer crossings, cutting profitability.


Safety checks ordered on all roll-on, roll-off ferries by Scandinavian governments since the disaster have shown up minor faults in several ships, but at least two ships have been withdrawn in the past 48 hours because of bow problems.


A Danish-Swedish ferry was withdrawn from its route between western Sweden and northern Denmark on Monday after a sea inspector found faults with its bow door, the company said.


The Lion Prince, operated by the Lion Ferry line, was inspected in the Swedish port Varberg on Monday morning and barred from departing for Grenaa on the Danish Jutland peninsula, company spokesman Gunnar Bolin said.


In London, shipping company Stena Sealing was quoted as saying that a Swedish-owned ferry traveled from Wales to Ireland and back last month even though the crew knew that a locking pin on a bow door had sheared.


Stena Sealink told The Daily Telegraph that the 23,000-ton Stena Felicity was withdrawn from service Friday and would be examined by an inspector from the Department of Transport.