Sydney Harbour, from end to end, is barely 7 nautical miles. Looking at its countless inlets and harbors on a chart, though, is like trying to decipher a Rorschach test, and seeing its shores from the water is an exercise in limitless cultural diversity. As I sit on the bow of the 120-foot (36.6-meter) Oceanfast Sahana, cruising past the Sydney Opera House and beyond, I see architecture that looks classic European, then contemporary, then American Colonial. Lobster boats that would fare well in Maine cruise by, followed by express cruisers reminiscent of southeast Florida and seaplanes evocative of the Pacific Northwest. An occasional military craft reminds me of cruising in Maryland near the U.S. Naval Academy at Annapolis.

I look to starboard and see the cityscape, a blend of skyscrapers and historic buildings alongside the Sydney Harbour Bridge’s 440-foot-tall (134-meter) steel arch. Waterway traffic buzzes like Newport Harbor in Rhode Island on a Saturday in July, and pedestrians scamper along the sidewalks and in the waterfront parks, looking just like the New Yorkers who wave at boats cruising up the Hudson River.

I look to port and see a handful of family boats at anchor next to a beach, all surrounded by a forest of eucalyptus (or gum trees, as the locals would say). The untouched landscape might as well be a back cove off the Intracoastal Waterway in Georgia or South Carolina, save for the occasional call of the native kookaburra bird.

A stewardess makes her way to the bow with a tray of hors d’oeuvres: compressed watermelon with Persian feta cheese and olive salt on French-style brioche. It would be followed by local Coffin Bay oysters with pickled cucumbers and a Vietnamese sauce. The chef’s style of cooking, she tells me, is fusion.

Of course it is.

Australia is a bucket-list charter destination for many Americans, a place whose cultural distinctness is born of variety. The continent is a cross-section of the world, and Sydney, one of its largest cities, offers a bit of everything.

Sahana, one of the largest yachts for charter here, is much the same. She alternates seasons between Sydney (October through April) and the Whitsundays/Great Barrier Reef region (April through September). For Americans booking a charter during the upcoming season, Capt. Paul Busk, a native Aussie, recommends three days in Sydney and three or four days along the nearby Hawkesbury River.

“This is city buzz,” he says of Sydney. “Go to the restaurants. And the harbor’s really cool at night. Christmas, New Year’s, Australia Day on January 25—the Sydney-Hobart race starts here, and that’s a massive event. They’ll use any excuse for fireworks here.’”

Busk is right about the enticing shoreside attractions, but during mealtimes, I’d stick with Clancy Atkinson, a freelance chef who, during my charter, was joining Sahana for his first stint with the yacht’s permanent crew. Atkinson is a Brisbane native who grew up in remote Darwin with what he calls “a lot of multicultural refugees. So the food scene is more advanced there, maybe more than anywhere else in the world. I learned by going to my mates’ houses. I’d be in the kitchen with their mums while they were outside playing.”

His passion led him to train with one of Australia’s most celebrated chefs, Russell Armstrong, and then to cater for companies including Louis Vuitton and Gucci during the days when Tom Ford was creative director.

“He had guidelines for everything to do with the brand: how much water goes in every glass, how many canapés on each tray,” Atkinson says. “From him, I learned precision. I had to. He was a perfectionist.”

Hence those colorful, flavorful and noticeably uniform watermelon bites with feta on brioche that I enjoyed on Sahana’s bow, one of several spaces on the yacht that were rebuilt after the 2008 launch got her current owner in 2013. He gutted the salon, staterooms and bridge deck aft, which went from carrying tenders to having a nearly full-beam bar along with sunning and shaded lounge space. The interior décor is now chic in grays and whites, including a prominent black-and-white photo of America’s favorite son, Ol’ Blue Eyes.

“He likes contemporary cool,” Busk says of Sahana’s owner. “He’s a jazz singer, and he loves Sinatra.”

The owner also is prone to seasickness, which is why Sahana has ABT-Trac at-rest stabilizers, two Seakeeper gyros and extra soundproofing in the guest areas, to ease noise and vibration. I, too, am haunted by the green monster, and I felt great aboard Sahana, both in busy Sydney Harbour and when we cruised from Palm Beach, in Pittwater, to Cowan Creek for water-sports fun.

Cowan Creek, just a few hours from Sydney at 10 knots, looked and felt like New England in September, with water warm enough for a refreshing swim and a handful of sandy beaches plus rocky trails amid a shoreline of green foliage and vacation homes.

“Outside of Christmas and Easter,” Busk says, “it’s not a lot of traffic here. You can get a bay to yourself.”

Another great spot, he says, is Middle Harbour.

“It’s really pretty,” Busk says. “You sit in Sugarloaf Bay, and it’s like rainforest. You have no idea you’re near a city.”

I believe it. And I’d be darn curious to stay on charter an extra few days, just to see whatever lies beyond the next harbor, too.

Must-Do Ashore: Sydney Opera House

In Australia, they call the structures above the Sydney Opera House “shells,” but it was sails that inspired Danish architect Jørn Utzon. His father was a ship designer, and Utzon used nautical charts to learn the landscape his building would occupy. Even the opera house’s practical elements are marine-inspired: There are no gutters; rain falls into gaps in the concrete walkways and then drains to the sea, as with scuppers.

The opera house puts on about 2,000 live performances each year in various theaters, and its 2,679-seat concert hall feels like a cathedral. The grand organ has 138 visible pipes out of 10,244 that continue behind a wall, and is believed to be the largest such organ in the world. One musician who tried to control its five keyboards, pedal board and 172 stops for air flow called the experience “like wrestling a monster.” sydneyoperahouse.com

Wines of Australia

Ultimate Winery Experiences Australia offers VIP experiences at 19 elite wineries (out of about 3,000 total) across the continent. At the Moorilla vineyard on Tasmania, for instance, tastings can pair with a private tour of Australia’s largest private art collection. Seppeltsfield in the Barossa Valley lets you taste your birth-year wine from the barrel, and St. Hugo in the Barossa Valley will name a row of vines in your honor, let you craft a red blend and deliver it bottled (cost: $150,000).

If you’d rather stay on the yacht near Sydney, then the wine can come to you. Our six-bottle tasting included a 2012 shiraz that’s only available at the Penfolds Magill Estate Cellar Door on Australia’s south-central coast. It tasted perfectly spice-forward as we sipped it near the iconic Sydney Harbour Bridge. ultimatewineryexperiences.com.au

For more information: Northrop & Johnson, 954 522 3344, northropandjohnson.com