Navy divers have attached lifting equipment to the wreckage of the Coast Guard helicopter Rescue 116, which is submerged off the coast of Mayo.

Search teams want to partially raise the wreckage as part of their search for two missing crew members - winch operator Paul Ormsby and winchman Ciaran Smith.

Once raised, it is hoped an unmanned vehicle will be able to search the area underneath the wreckage, which is located in waters off Blackrock Island (around 12 km from Blacksod in Co Mayo).

Weather conditions have continued to hamper the search efforts in recent days.

The Coast Guard's search & rescue operations manager, Gerard O'Flynn, explained: "Following on from a very successful [remote operated vehicle] operation overnight, navy divers were in the water this morning.

"They completed the tasks which were assigned to them in terms of securing lifting strops to the target."

However, he added the weather has deteriorated considerably and they are now assessing the situation.

The Air Accident Investigation Unit (AAIU) yesterday confirmed that Rescue 116's black box has shown there were no mechanical issues with the helicopter.

The examination of the device is ongoing and a preliminary report is set to be completed shortly.

Captains Dara Fitzpatrick and Mark Duffy both died following the crash last month.