Clean sweeps to Great Britain's Luke Patience and Stuart Bithell in the blue fleet and Australia's Mathew Belcher and Malcolm Page in the yellow saw Great Britain and Australia both on equal points at the top of the leader board in the Men's 470.
With racing cancelled on Tuesday due to electrical storms, Wednesday's competition became crunch time for gold and silver fleet allocations.
World #1 Belcher said he and Page couldn't complain about their result after racing in near perfect sea breeze conditions. "We are really looking forward to the finals," he said.
The scheduled showdown between the 2011 and 2010 European champions in the blue fleet didn't disappoint. It was a constant battle between 2011 champions Sime Fantela and Igor Marenic (CRO) and 2010 champs Panagiotis Mantis and Pavlos Kagialis (GRE), with the Croatians finishing the day in third overall and the Greek duo now fourth.
The men's 470 races are scheduled to begin at 14:00 Perth time on the Success course on Thursday.
Finn World #2 Giles Scott (GBR) continued his impressive form on the water, moving from fourth to second overall with two wins and a second on Wednesday.
Racing in the Yellow fleet, Scott was followed closely for most of the day in the 18-20 knots sea breeze by Pieter-Jan Postma (NED), who managed to edge him in Race 5.
After discarding his worst result, Postma took the overall lead by one point ahead of Scott, with Ben Ainslie (GBR) a further point behind. Ainslie has dropped from first to third in the overall rankings after collecting nine points for the day.
Disqualifications dominated the first blue fleet race of the day, with 11 sailors receiving Black Flag Disqualifications. They included World #1 Edward Wright (GBR), day-one winner Rafa Trujillo (ESP), and Olympic silver medallist Zach Railey (USA).
Four sailors in the Yellow fleet's third race were also disqualified for the same reason.
The mass disqualifications gave Jonathan Lobert (FRA) his only win so far in the competition. Trujillo also put his earlier penalty behind him, placing well for the rest of the day.
Finals Series racing in the Finn class is scheduled to begin at 14:00 local time Thursday on the Leighton course.
Conditions proved challenging in the Women's RS:X event with athletes tested by 15 knot winds following days of light winds.
However after three races in both fleets, Israel's Lee Korzits holds the lead from Bryony Shaw (GBR) and Marina Alabau (ESP).
World #1 Blanca Manchon is languishing in 13th place overall while windsurfing veterans Alessandra Sensini (ITA) and Jessica Crisp (AUS) are in 15th and 16 places respectively.
The Women's RS:X Finals Series racing is scheduled to begin on the Centre course at 12:00 Perth time on Thursday.
Sailors on the water for the third day of the Laser Radial competition enjoyed perfect conditions but encountered dramatic changes in fortunes.
Race 3 started in 11-15 knots which picked up to a 20 knot sea breeze by Race 5, with swell and chop to contend with.
In the first race of the Yellow fleet, the winner of the last two world championships, Sari Multala (FIN), was back to winning ways in Race 3 for the Yellow fleet. Alison Young (GBR) worked her way up from fifth place to second while Ashley Stoddart (AUS) finished a creditable third, after rounding the first leg in tenth place.
Sari Multala also won the second race of the day. "In the first two races I had a really good start," she said. "I could do what I wanted to do. There were some speed differences in the winds which helped," Multala said.
Evi Van Acker (BEL) and Paige Railey (USA) were back on form finishing second and third.
Alison Young (GBR) saved her best for last to win race 5 in the Yellow fleet. "The first two races weren't too great. Today I had three good races and I am happy with it," she said.
In the Blue fleet, Charlotte Dobson (GBR) put her 34th place behind her and posted her first win of the series. Annalise Murphy (IRL) and Veronika Fenclova (CZE) came from outside the top eight to finish second and third respectively in Race 3.
World #1, Marit Bouwmeester (NED), did not have a good start and chose the wrong side of the course. However, she managed to claw her way back into race to take tenth place after rounding mark one in 33rd position. "I tried to forget about it and sail how I normally do," Bouwmeester said about her comeback.
In Race 4, World #13, Murphy won her second race of the series. "I was leading from start to finish and pulled out quite a lot and it was a good feeling to get so far ahead," Murphy said. World champion Bouwmeester came second with Charlotte Dobson (GBR) third. It took Bouwmeester five races to score her first win in Perth 2011, and that was Race 5 for the blue fleet. Murphy's win saw her skyrocket from 26nd to second on the leader board. Bouwmeester (NED) remains in third place.
Finals Series racing for Laser Radial is scheduled to begin on the Parmelia course at 12:00 local time on Thursday.
Women's Match Racing
Fleeting appearances from the elusive 'Fremantle Doctor' sea breeze set the pace in the Women's Match Racing on Wednesday with winds of 13 to 18 knots proving a challenge for some of the crews in Group B, despite earlier wind shifts that enabled the first four flights to engage in tactical racing.
Throughout flights 34 to 43, some crews struggled to clear and fill their spinnaker while others used the windward marks to make strategic advances in the final downwind run.
Morning racing was highlighted by the tense match between defending world champion Claire Leroy (FRA) and Spain's Silvia Roca. Leroy was unable to ward off a well-executive jibe from Roca, forcing the French crew to sail in Roca's backwind. Despite the loss, Leroy's crew share equal first place the Women's Match Racing round robin with seven wins and a single loss.
During the afternoon flights, teams began sailing at higher angles to keep their sails in full motion as the wind decreased in Fremantle's Inner Harbour.
Australian sailors seemed to have more success, with led by Olivia Price (AUS), out sailing her opponents to post a tally of seven wins and three losses to join Leroy's French team in equal first overall in the round robin stage.
Spain's two boats, skippered by Tamara Echegoyen and Roca share third place overall.
Women's Match Racing is scheduled to continue at 10:00 Perth time on Thursday on the Harbour course.
The Perth 2011 ISAF Sailing World Championships website will bring you results, tracking, live updates and all the latest news both on and off the water.