A 16ft cabin cruiser capsized in waters off Portronan Pier on the north coast of Ireland at around midday on Tuesday.
A couple staying in a holiday home near to the pier raised the alarm when they heard cries coming from the water.
Thomas was airlifted to hospital in Northern Ireland but sadly died late on Tuesday night.
His uncle Gerry Doherty, also died in the incident after the small fishing boat capsized.
A third man in his 50s, named locally as Dessie Keenan who Thomas was believed to be living with in Ireland, survived the incident and has since been released from hospital.
Tributes have been posted on Facebook.
Thomas’ cousin Eireann Fletcher said: “Honestly can’t believe this.
“Rest in peace to my Uncle Gerry and my baby cousin Thomas.”
Lyle Miller commented: “No one will ever compare to u mate, were like a genuine wee brother.”
Liam Heatherill wrote: “Rest in peace, Tam. Like a wee brother to us all you will never be forgotten.”
Around 40 emergency personnel were involved in the response. Joe Joyce of Lough Swilly RNLI told our sister paper the Derry Journal that the men had left the pier shortly after 9am on Tuesday morning.
He said: “At around 12pm, they got into difficulty - the nature of that, we are not sure. It resulted in the boat being swamped and capsizing. The men entered the water, which they were in for a considerable amount of time, around three and a half to four hours.”
The alarm was raised at 3.30pm, when a nearby couple heard a shout for help and contacted Malin Head Coast Guard Station.
The station immediately tasked Lough Swilly RNLI’s two lifeboats, Greencastle Coastguard and the Sligo 118 coastguard helicopter to the scene.
At the same time, the Officer in Charge at Malin Head Coast Guard went to the scene and spotted people in the water.
The Malin Head station also put out a ‘Mayday’ request to all local fishing vessels at sea in the Malin area to identify themselves and aid with the search.
The crew of a local fishing boat also heard the cries for help. The man believed to be Dessie Keenan, was seen clinging to a buoy. He was transferred to Altnagelvin Hospital and has since been discharged.
Volunteers from Greencastle Coastguard, some of whom had been working in nearby Malin town, commenced an immediate shore search. The 118 helicopter located Thomas in the water. He was airlifted and taken to Altnagelvin Hospital. He sadly passed away.
Mr Joyce said that the capsized boat and debris trail were located around half a mile from Portronan Pier.
The RNLI, Coastguard and local boats immediately began a search of the surrounding area. In conjunction, a shore search got underway by members of Greencastle Coastguard and An Garda Siochana, assisted by members of the public.
Mr Joyce described the terrain as “very difficult” and “treacherous” and added that there was an expanse of shoreline due to the tide being out.
The third man was then spotted on rocks near Banba’s Crown (The Tower) by the public, who alerted the emergency services. Two members of the RNLI swam out to the location to aid the coastguard. Due to the nature of the terrain the decision was taken to stretcher the man to the road, which was a “difficult task.” A doctor at the scene pronounced the man dead and he was taken to Letterkenny General Hospital for a post-mortem.
Local boats, in conjunction with the RNLI, took the capsized vessel to Malin pier, where it was recovered by the RNLI and local fishermen on to a trailer, before being handed over to Gardai.
Mr Joyce expressed the sympathies of the Lough Swilly RNLI to the families of the men. He also thanked the local fishermen who responded to the request for assistance.
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