A man swept overboard after being hit by a “killer” wave was dramatically rescued as he struggled in the water.

Skipper Dan Oliver, 40, was on the deck of his yacht Lady Cilla yesterday with the rest of his crew when a three-metre wave hit him head on and he was plunged into the 12C water outside Brighton Marina.

Mr Oliver was knocked into the water shortly after 1pm but the 45mph winds prevented his three teammates pulling him back on board.

They sent out a Mayday call on the yacht’s radio and the volunteer RNLI crew was scrambled.

Mr Oliver, an experienced yachtsman who was preparing to take part in the Royal Escape 2011 race today, was losing consciousness as the rescuers tried to get hold of him in near gale force winds.

Fortunately he was wearing a life jacket that inflated when he hit the water and that was attached by a safety line to his boat so he couldn’t be swept away and eventually the RNLI crewmen were able to pull him on board.

The coastguard had a helicopter hovering above in case Mr Oliver needed to be flown to hospital urgently.

RNLI senior helmsman Mark Smith said the yachtsmen had not done anything wrong but had been struck by “one killer wave”.