The problems have been caused by strong winds that have pushed the ice towards the Swedish east coast, and packing it sometimes several metres thick. But Johny Lindvall, controller at the ice breaker unit of the Swedish Maritime Administration (SMA) told Swedish Radio News that the captains of some ferries that got stuck by Kapellskär just north of Stockholm had ignored warnings from the SMA:
"We always try to direct the traffic the easiest way and be available where the difficulties are. But then there are of course some people who want to make their own decisions and that often throws our plans and then others suffer for these mistakes".
Seven icebreakers are working round the clock to keep the ships in the Baltic Sea moving.
This is the worst Baltic freeze for 15 years. Ice banks between 40 and 50 centimetres thick have caused a number of merchant ships and passengers ferries to become stuck or forced to stay in port.
Earlier Radio Sweden' Dave Russel spoke to Jonhy Lindvall, who said the ice is a real problem.
"About 85 percent of the trade to and from Sweden comes via the sea. There's a lot of industry in the north affected, particularly the paper industry, " he said.
"The ice wouldn't usually be a problem for the merchant ships, the problem now is that it's very windy, about 20 metres per second and that means that the ice is moving rapidly, there are lots of ridges with ice that's making it problematic for the ships, so they need help from the ice breakers to get back to the different ports," he added.
The winds are set to ease during Friday but the ice will stay for one to two months.