You don't need a yacht - let alone an America's Cup class one - to enjoy the sights of Sydney Harbour. Bring your running shoes and try this run shown in the Google Earth picture above, which was a good way of saying goodbye before the 20 hours flight back home.
Start at the Sydney Marriott, turn right and run down past Captain Cook's statue, across the bridge by the Art Gallery of NSW, into the botanic gardens, out to Mrs Macquaries point, admire the view, round to the Opera House, admire the view again, then back past the art gallery and back via Archibald Fountain and the Anzac War Memorial.
If you do it in under 30 minutes you are way too fit and have no soul for the views are wonderful and well worth stopping for five minutes or even more...