The Winston Churchill, a roll-on roll-off ferry operated by DFDS Scandinavian Seaways, was held up for almost a day with 500 passengers on board at Esbjerg, Denmark, while the work was carried out.
The ship, built in 1967, operates two return trips between Esbjerg and Newcastle weekly from April to October and was due to be put in dry dock for maintenance.
Ebbe Pedersen, the managing director of DFDS, said: 'We thought it better to weld up the doors rather than wait for a replacement seal.' He said that there would be some delay to passengers getting off the ferry as they would use the stern ramp but it would not delay the schedule which allows for several hours in each port.
An Oostende Lines cross-Channel ferry, the Prins Albert, broke down with rudder failure as it left Ramsgate on the 5.30am sailing to Ostend yesterday. A spokeswoman for the company said: 'An oil leak caused rudder failure just as the boat was pulling away. It used its boosters to reach the open sea where repairs were carried out within half an hour.'
Stena Sealink yesterday had to cancel a sailing between Dieppe and Newhaven and the return journey after it was delayed by two sets of inspectors called in by the French authorities and the shipping line's classification society, Bureau Veritas. A spokesman said: 'It just happened that two sets of inspectors arrived at the same time and we thought it best to cancel the two trips.'
In Finland yesterday coastguards reported that the searchers had still not located the bow door of the Estonia, raising questions about when the door was broken off from the ship. A coastguard spokesman said: 'We have carried out a search over around 200 hectares, with the aid of sonars, near the ship and on the route it was presumed to have taken before it went down.'
He said they were 90 per cent sure that the bow door was not in the zone where the ferry sank. It capsized last Wednesday on its way to Stockholm from the Estonian capital Tallinn with the loss of 912 of the 1,049 people aboard.
As the search goes on, the pressure for major changes to the ferry industry appears to be growing in Scandinavia. 'This industry must ask for help - we're in a bad way,' said Robert Akerlund, in charge of ship operations at Sweden's Stena Marine, operator of the world's largest ferry fleet.
'We have made a big mistake and we need to speed up (improvements to safety),' he told a conference on marine safety in Stockholm yesterday.
It is expected that the Swedes will be pressing the International Maritime Organisaton for major changes in ferry regulations, just as the British did after the Herald of Free Enterprise disaster in 1987.