They were presumed drowned by the treacherous currents, their bodies were never found.

Thankfully Lurgan swimmer Turlough O'Hagan learned this information after completing the swim leg of the Escape from Alcatraz triathlon, which commemorates this grisly fact.

Turlough and Newry man Geoff McCracken travelled with two other transplant athletes from Liverpool to meet up with American transplant competitors in San Francisco to form relays for the triathlon.

"It was a fantastic experience. On the day of the swim we were up at 4.30am to get down to Fisherman's Wharf to board the huge ferry that was taking the 1,800 competitors out to the start.

“The ferry set off at 7am and the atmosphere on board was bristling with nervous excitement and then when it did a slow sweep of Alcatraz the tension was electric.

“The PA system then blared ‘five minutes to start’, I was so hyped I was nearly over the side and away. The swimmers were going off in waves of about 100 and luckily we were in the second lot.

Turlough recalled: “At last I was in the water. I was so excited I can't remember hitting the water. One part of my brain was saying, "Slow it down, use the first the first five minutes as a warm up" but the bigger part was screaming "Get your head down - go for it!"

“It was chaos, there were swimmers everywhere, people swimming over me, I was swimming over others and was getting kicked and punched and the waves were tossing me all over the place....it was great!

Turlough told how US swimmer Ray Valesco had swam the race before and gave them good advice.

“We had a marker, a big domed building just behind the beach we were aiming for, about one and a half mile straight ahead.

“Due to the strong currents he told us to swim at ‘10 to the hour’ for the first half mile and curve round towards the dome.

“About halfway the water got extremely rough and choppy, it was the hardest conditions I ever swam in.

”Thankfully that passed and I made steady headway towards the beach. At last I was there but not finished, I got on my runners and jogged one mile to hand over to the cyclist.

“I was completely bushed but the feeling of achievement was out of this world.The fact I was first transplant swimmer home and also second in my age group were cream on top. It was an experience I will always remember and treasure, it has whetted my appetite for open water swimming.”

Turlough will keep up his open water training during the summer because along with Geoff and five other transplant swimmers they will be forming a relay to swim the English Channel in late August.

They are doing this to increase organ donor awareness and to show transplant patients can have an active and exciting life after a transplant.

Any donations would be greatly appreciated, Turlough can be contacted through the Blackthorn Gift Shop, 33 William Street, Lurgan, 3832 9699.