Plain sailing? It could be like running on pot-holes, says Olympic hopeful Ainslie

But there are no special effects involved in the emerald seaweed carpet which an ill wind blew back into the sailing venue at Qingdao last weekend, turning the Yellow Sea green.

Stormy waters: Ben Ainslie faces a tough time in Qingdao.

'Imagine running the 100metres on a track covered in pot holes. That's what it can be like,' Ben Ainslie told Sportsmail from his base in China.

'A fleet of little Chinese fishing boats outside the course area is trying to pick all the weed out. They are doing a great job, bless 'em. But some days are better than others. Today was not so good, though a lot better than three or four weeks ago.

'Then, you could not really have raced. It would just be unfair. Now, it is not great, but livable.'

At the height of the problem, one third of the sailing area was covered in a green gunge. Thousands of volunteers, fishermen and even the Chinese navy were enlisted to break up and remove the foul-smelling slime, some of which had accumulated into dense slabs the size of football pitches.

As if smog, strong currents and little or no wind were not enough for the world's top sailors to have to negotiate.

'You have to sail round it,' Ainslie explained. 'You try to avoid it best you can by altering your course a little bit. But you do not want to change course too much because you are giving away ground.

'Sometimes you can't help but run over a patch and then you have to check whether it has stuck to your rudder or your keel. If it has, you have to clean it off and that can cost you three or four boat lengths. It is a real annoyance and it may well be something we have to deal with.'

It is all very well maintaining that the conditions are the same for everyone. The expected light winds, leading to possibly shortened races and curtailed schedules, will be a great leveller, with medals being decided less on ability and more on good fortune.

'I am not saying it will be a complete lottery,' Ainslie said. 'But I fully expect some of the classes will not sail the full series of races and there will be some really strange results. It is going to be the toughest challenge any of us have ever raced in.'

Going green: Volunteers try to clear the algae threatening to disrupt the Olympic sailing event.

As one of the strongest sailing nations, with half a dozen or so gilt-edged medal prospects, Great Britain has more than most to worry about from being turned over and class being neutered.

'Without a shadow of a doubt we have got the best sailing team on paper ever sent to an Olympics,' Ainslie said. 'But when you look at this venue we are facing a game of snakes and ladders. Anything can happen. It is better that we set our sights conservatively, reduce the pressure on our sailors and see what happens at the end of it. That said, we are happy, confident and going fast in training.'

Ainslie, as a double gold medallist at Sydney and Athens following a silver on his debut in Atlanta in 1996, is the standard bearer of the British team and a hot favourite for victory in the Finn class. He has not lost a regatta since the European Championships in 2004. The subsequent unbeaten sequence includes both test competitions in Qingdao when he won nine out of 11 races and five out of eight respectively.

He insists that such domination is misleading. 'On the basis of these results you would think it would be easy for me,' he said. 'The whole fleet has made massive gains, however, and the competition is a lot closer. I was eight points behind going into the final race of the European Championships earlier this year and had to sail a bit of a blinder to get out of that one.'

Since the modest but ruthless Ainslie never refers to himself in such glowing terms, that must amount to something of an understatement.

Ainslie has been in Qingdao for three weeks sailing against, among others, Ed Wright, the man he had to beat in a race-off for selection to the British team. That is a measure of British sailing morale.

Ainslie is impressed by the facilities in China. He said: 'As a sailing venue, shoreside it is way above anything I have seen before. It is phenomenal, the size of the harbour and the accommodation for sailors.'

A pity about the actual water where, unlike what those nautical animals the Owl and the Pussycat encountered, it is the sea that is pea green. And in no way beautiful.