Giles Scott won GB's 17th gold in the men's finn sailing on Tuesday as Hannah Mills and Saskia Clark guaranteed another will follow.
Scott needed only to finish the final race of the competition to secure gold and a fifth straight British success in the event following Sir Ben Ainslie's hat-trick of titles and Iain Percy's 2000 win.
And the 29-year-old obliged with a second-placed finish behind United States sailor Caleb Paine.
Paine's victory was good enough to earn him a bronze medal, with silver going to Slovenia's Vasilij Zbogar.
Wednesday's women's 470 medal race will now be a lap of honour for Mills and Clark, meanwhile, after they finished the day with an unassailable lead.
The British pair are 20 points better off than their nearest rivals - New Zealand's Jo Aleh and Olivia Pownie - and are guaranteed to go one better than their silver-medal finish in London four years ago.
Ireland's Annalise Murphy earlier won a silver medal in the women's laser radial event, four years after she finished fourth in London.
Murphy told RTE: "I don't know whether I'm laughing or crying, I was just so happy with how I sailed this week and that last race I just put everything together really well. I'm over the moon."