Protests dominated a tense pre-start tactical battle between two of the favoured challengers for the America’s Cup after AmericaOne refused to accept a penalty imposed by on the water umpires this afternoon.

AmericaOne, representing the St Francis Yacht Club, and Asura of the Japanese club Nippon, collided shortly before the start of their Louis Vuitton Cup race, with the resulting rows destined to be heard by the cup’s international jury after the end of racing tonight. After the collision, the Paul Cayard-skippered boat was penalised 40 seconds.

But the American then requested a delay to the start of the race, saying technical repairs were needed on the boat though it was not clear whether those repairs had anything to do with the collision.

While that request was allowed, the umpires then said the 40 second penalty would still apply at the start of the race.

Cayard refused to accept this, and lodged a protest.

The two yachts then resumed their starting manouevres, and several times came within centimetres of colliding with both Cayard and Asura’s skipper Peter Gilmour initially flying protest flags, though no penalties were awarded during the second pre-start.

AmericaOne was holding a slight edge as the two boats finally embarked on their first leg.