Separate searches were under way yesterday to find two men who were reported missing from their boats.
One was a Dublin yachtsman missing off the Co Antrim coast, the other a naval crewman who went missing off the Co Cork coast.
A search for the missing Dublin yachtsman began after the boat he was sailing was found drifting unmanned off the east coast of Co Antrim on Saturday.
The RUC was checking hotels, guesthouses and B&Bs along the Co Antrim coast, trying to piece together the movements of Mr Robert McCune, who was in his 60s and from Templeogue.
An extensive air and sea search after the boat was found at 10.15 p.m. on Saturday evening was called off at 5.20 a.m. yesterday morning, said Belfast Coastguard.
The lifeboat from Red Bay, local coastguards, a helicopter from Dublin and an RAF Nimrod all took part in the search.
A further search of the coastline yesterday found no trace of Mr McCune. Weather conditions were very good in the area, and there was no sign of damage to the boat.
After the yacht was found, it was towed into Red Bay, five miles north of Larne.
Belfast Coastguard said all Mr McCune's belongings were still on board. "Exactly what happened, we don't know."
The Coastguard said Mr McCune was last seen on Wednesday, June 20th, when he went to a local post office. He spoke to his sister by phone the following day.
Off the coast of Co Cork, an intensive sea search was conducted after a 36-year-old sailor was reported missing off the naval vessel, Le Roisin, yesterday morning.
Petty Officer Cook T.J. Doyle from Tullow, Co Carlow, was last seen on board the vessel shortly after 7.30 a.m.
His disappearance was not noted until the vessel dropped anchor at Ballycotton, east Cork, at 8.45 a.m.
Mr Doyle had been living in Cobh, Co Cork, and is a married father of two children aged 10 and eight.
The LE Roisin was joined in the search by the LE Aoife and the LE Eithne, the Ballycotton and Youghal lifeboats, the Coast Guard helicopter from Shannon and an Air Corps helicopter from Waterford, as well as local Coast Guard units.