Officials involved in the search for the missing crewmen of R116 have said it could be five days before they can mount an operation to retrieve the black box and wreckage due to bad weather conditions.
The search for missing Capt Mark Duffy, winch operator Paul Ormsby and winchman Ciaran Smith will continue today.
However, bad weather has continued to hamper the search efforts in Blacksod, Co Mayo.
Yesterday, family and friends of the three missing men watched from the harbour as the ship ILV Granuaile made its way into the bay.
The specially equipped vessel - designed to carry out operations in difficult conditions - will help in the operation to retrieve the black box and fuselage of the crashed helicopter.
A signal from the black box has been located 60 metres from Blackrock. The main frame of the helicopter is believed to be close by.
It is hoped the remains of the men will be found there.
There was a small improvement in conditions yesterday, which allowed sonar searches of the area.
The Granuaile, run by the Commissioner of Irish Lights, stayed anchored in the bay while sonar scans were carried out - a lead operation for the eventual use of the ship to attempt to retrieve the wreckage.
It had spent the previous days in Galway being fitted out to help in the search.
A remotely operated vehicle, which can be used to access difficult-to-reach undersea areas, was among the specialist equipment loaded on to the ship.
The ship also has a 20-tonne crane, giving it the capability to lift wreckage.
It has emerged that any retrieval attempt may not be possible until the end of the week.
A meeting was called by the coast guard last night to decide how to proceed and discuss the results of the scans.
Declan Geoghegan, from the Irish Coast Guard, said it was unlikely that attempts could be made today to retrieve anything from the area around Blackrock Lighthouse.
"There may be an opportunity on Tuesday," he said.
After this, it is understood conditions will again prove difficult until at least Friday, with gale force winds forecast on the west coast.
Mr Geoghegan said there were swells of three metres yesterday as local fishing vessels used sonar to scan the area.
Meanwhile, the funeral of Capt Dara Fitzpatrick, the only crew member to have been recovered, took place in Glencullen, south Dublin, on Saturday.
Uniformed members of the Irish Coast Guard, mountain rescue, Air Corps and other rescue services joined with Capt Fitzpatrick's three-year-old son Fionn, her parents and siblings in bidding farewell.
President Michael D Higgins, Taoiseach Enda Kenny and Fianna Fail leader Micheal Martin were in attendance.
Addressing the congregation, Capt Fitzpatrick's sister Niamh had one simple plea on behalf of her sister's missing crew.
"God, you owe us one - bring them home," she said.
Mr Kenny was expected to visit the search and rescue base in Blacksod this morning to meet the families of the missing crew and speak to those involved in the search.
While final details of Mr Kenny's visit were being ironed out last night, it is understood the meetings will be private.