The full extent of the problems the Steam Packet could face if new wind farms are built has been laid bare.
The company estimates that the proposed developments could put 50 more sailings at an increased risk of disruption or cancellation.
More windmills at sea mean that the number of routes ships could take is restricted – meaning more sailings would be cancelled.
Although passengers are unaware of this, the ferries use different routes depending on weather conditions.
The details come to light as the company has had a particularly difficult few weeks because of the weather.
Since November 1, there have been about 12 sailings that were disrupted or cancelled.
Disruption not only leads to inconvenience for passengers but it means that many shops’ shelves are empty as retailers rely on morning deliveries.
Daniel Walker, the Steam Packet’s marketing manager, said: ‘It is hard to draw direct comparisons year to year as the weather isn’t the only factor that can play a part in disruptions and cancellations.
‘However, looking at 2019 total year figures, the last full year of “normal” sailing data, we estimate about 50 sailings would have been at increased risk of cancellation due to the inability to use weather routing, which is approximately 2.5% of all sailings in 2019.’
Mr Walker added: ‘That is approximately 1.3% of either Douglas to Heysham or Heysham to Douglas sailings and 5.4% of either Douglas to Liverpool or Liverpool to Douglas sailings.
‘Manannan requires weather routing more than Ben-my-Chree due to the nature of her design. The sea route to Liverpool is also more exposed than the route to Heysham.’
The Steam Packet warned that the proposed wind farms won’t just have an impact on disruptions and cancellations.
Mr Walker said: ‘Every sailing to or from Heysham will have to sail between one and five nautical miles extra, which is doubled per return trip, adding to sailing times, fuel use and emissions.
‘If we are not able to utilise the weather routing due to the presence of wind farms, even where that doesn’t lead to cancellations, it could still result in reduced passenger comfort, longer journey times through reduced speeds and so on.’
An initial consultation is taking place to gather people’s views on two new offshore wind farms being developed by energy companies EnBW and BP in the Irish Sea, called Morecambe and Morgan, which will end on December 13.
The wind farms will be located around 20km to 30km to the south east of the island.
They are expected to generate enough clean electricity to power about 3.4 million UK households.
The Steam Packet has been urging the public to think about ‘the full picture’ regarding the proposed wind farms and its impact on ferry services.
Mr Walker said: ‘The Isle of Man Steam Packet Company is keen to see a reduction in carbon emissions and is supportive of efforts to improve sustainability and energy independence.
‘ However, it is important that sustainability also factors in concerns around maintaining lifeline services to island communities like ours.’
Steam Packet managing director Brian Thomson said: ‘The safety of navigation for ships when sailing through the wind farm corridors is a key concern.
‘The lack of open sea room for navigating in rough weather is likely to increase the risk of cancellations on the island’s lifeline routes.’