Telefonica Black is planning to change the rudders on its Volvo Open 70 in Singapore less than five days before the start of the fourth leg from Singapore to Qingdao.

The decision taken by the team will affect only Telefonica Black and is designed to improve the performance of the Volvo 70 in heavy downwind conditions. Both Telefonica Black and Telefonica Blue have suffered at times compared to the competition in big winds and waves in the first three legs.

The new rudders are identical in shape to the original ones but with 27 per cent increased length and volume. Telefonica Black will trial the new rudders with a view to also replacing the rudders on Telefonica Blue if the team feels the change is successful.

Under the rules, the team will take a three point penalty for changing the rudders, but are sure the improvement in performance will make it worthwhile.

Pedro Campos, Telefonica CEO said: "This is a change that we have been thinking about since last October. We are looking to optimise the performance of our boats for downwind racing and our engineers have told us that this will improve Telefonica Black's performance.

"We have chosen Telefonica Black as the test boat to sacrifice three points on the general standings. With 80 points still to play for in the race we are really sure that we will recover the points in the next legs with the improvements we have made on the boats."

Telefonica Black also announced that Pachi Rivero, 44, will replace Argentinian watch leader Santiago Lange for the next two legs.

"I am delighted to come back to the team as crew," said Rivero who returned to his home Santander after leaving the crew at the end of the first leg in Cape Town.

"After we finished the leg between Alicante and Cape Town it was sad for me to leave and I have been waiting ever since to be asked back. I have been in Spain getting ready and training really hard in the gym in case I was asked to come back to the boat."