A black box signal has been detected
Bad weather could hamper the continuing search for three missing crew members from Coast Guard Rescue 116.
A black box signal has been detected by the search team, which is helping to pinpoint the location of the suspected crash site off the Mayo coast.
The search operation will move to a smaller vessel as soon as it is safe to do so, with divers expected to be sent to retrieve the recorder.
However conditions are too rough to send in divers.
During searches on Tuesday, the Coast Guard said debris was found spread over a wide area.
While the LE Eithne maintained a position near Blacksod overnight, and the search is resuming from first light.
Navy and garda divers, Ballyglass and Achill lifeboats, the LÉ Roisin, a fixed wing aircraft and two helicopters are all involved in the operation.
Captain Dara Fitzpatrick died after being recovered from the water on Tuesday - but Mark Duffy, Paul Ormsby and Ciaran Smith are still missing.
Gerard O'Flynn of the Coast Guard says the forecast is not great.
"the weather outlook is challenging and it does not look good.
"And I would be fearful at this point that it could hamper operations.
"The forecast is bad through the weekend, so that is going to be a particular challenge - and unfortunetly could lead to some delays.
"But as the day goes by, it will be more evident how much progress can be made", he added.