Ainslie won gold at the Sydney, Athens and Beijing Olympics
Ben Ainslie and Nick Thompson secured individual World Cup golds while Alexandra Rickham and Niki Birrell also won for Team GBR in the Skud class.
Triple Olympic champion Ainslie was the winner of the Finn class as Ed Wright took silver and Giles Scott bronze to complete a British clean sweep.
Paralympians Rickham and Birrell won all eight races to dominate the Skud.
And Thompson emerged victorious in the Laser series in patchy wind conditions at Sandringham Yacht Club in Melbourne.
Ainslie, 33, headed into the final race with a six-point lead over Scott, with Wright a further point behind in third.
"Ed was going right and Giles was going left. I went with Giles," said Ainslie of the medal race. "It [the wind] was slowly clocking left but there was a big right hand shift which lifted Ed."
Wright went on to finish the race in second to win silver, while Scott placed third.
Fourth position was sufficient to secure gold for Ainslie, who last week rose to number one in sailing's open world match race rankings.
Another of Ainslie's Finn team-mates, Andrew Mills, finished in eighth position.
Two-time world champions Rickham and Birrell, who had also won the Sail Sydney warm-up event, enjoyed a flawless regatta in their two-person keelboat to triumph by a 10-point margin.
World silver medallist Thompson struggled in his final race but finished ahead of his two nearest rivals, Australians Tom Burton and Tom Slingsby, to hang on to gold.
In the Laser Radial fleet, Andrea Brewster and Charlotte Dobson were the top-ranked Britons, in sixth and eighth respectively.