Police said the alarm was raised at 4.52pm on Saturday (June 8) by friends of the boy who had been unable to assist him when he got into difficulty off the beach close to the marina. He was recovered from the water about 15 minutes later.
Police have praised his 12-year-old friend for his clear and calm reports on the telephone to an emergency call taker, which they described as 'amazing' and probably life-saving.
While winds are expected to drop over the next 24 hours, the sea is likely to remain rough for some time and police have warned of the dangers of entering the water, even for a paddle.
Chief Inspector Roy Hodder said: "It is very easy for your feet to be swept from under you and you can be dragged into deep water and some way offshore in next to no time. Please take care and also make sure that even though it all looks very exciting, youngsters are fully aware of the dangers.
“This young lad was lucky and a lot of the credit for his safe rescue must go to his friend who showed remarkable calm on the phone to us and whose amazing clarity of information enabled his swift recovery from the water by the RNLI team.”