Antarctica ranks high among travel dreams these days.

Actually going is another thing. Consider the price tag: Expedition cruises cost between $7,000 and $35,000. Then factor in the probability of stomach-churning days on the often-turbulent Drake Passage — or the high cost of flying over the Drake for the squeamish. Temperatures generally range in the easily endured low 20s to 30s during November through March, when ships sail, but occasional windstorms add to the chill.

Still, the remote icy region grows ever more enticing. A record 51,707 travelers visited Antarctica in the 2017-18 season, most arriving by one of 60 ships sailing from South America or New Zealand.

For travelers heading to the extreme south, the question is, which ship?

Though there is a tendency to think all Antarctic voyages see the same scenery — icebergs and penguins, right? — in fact, Antarctic voyages vary a great deal. Some hover at sub-Antarctic islands, spotting penguins aplenty yet landing just once, if at all, on Antarctica proper. Some passengers will be lucky to get ashore twice on their journey. Other ships set passengers ashore twice a day with multiple stops on islands and the Antarctic Peninsula, packing in hikes, wildlife sightings and visits to historic sites.

There are factors involved that few travelers know, and price doesn't tell the whole story.

In November 2017, I sailed from Ushuaia, Argentina, on m/v Ortelius, with Oceanwide Expeditions. This sail's quest was to reach an emperor penguin colony, and those birds called to me as they did to many who saw film "March of the Penguins."

Emperor penguins are rarely seen by Antarctic visitors, though, because most colonies dwell below the Antarctic Circle amid unnavigable sea ice. The exception is a colony of 7,000 emperors on Snow Hill Island in the Weddell Sea, just below the Antarctic Peninsula.

Venturing into the Weddell Sea is daunting. Until a ship reaches its waters, a captain can't know whether spring thaw has turned the winter-frozen sea to a navigable margarita or hull-slashing ice chunks. Only icebreakers and ships with the highest ice class rating dare to traverse the sea, and only ships carrying helicopters can hope to ferry passengers across the treacherous sea ice of Snow Hill Island.

No ship had managed to reach the emperor colony since 2013.

Though the Ortelius had an uncertain itinerary, the fact is that no Antarctic voyage has a solid plan. A voyage's intended itinerary is really a wish list of landings, determined by ice and weather. Every captain will agree that Antarctica is at the helm. There are no cruise ship ports in Antarctica, so landings are crude, with passengers bounced to shore via motorized rubber rafts, or Zodiacs. When waves grow big and churlish, Zodiacs don't launch, lest passengers get bounced into the frigid sea.

Canceled stops are common on every voyage.

The only way to hedge against lost shore time is to choose a longer voyage, perhaps 12 to 14 days, keeping in mind that roughly four days are taken up sailing the landless Drake Passage.

There is another consideration if your goal is maximum time ashore. Although larger ships are attractive for more onboard amenities, smaller ships have a strong advantage when going ashore. That's because environmental regulations — set by the International Association of Antarctic Tour Operators — allow only 100 passengers ashore at a time. A small ship carrying 100 to 200 passengers can often ferry all passengers in the morning, then sail off to a second landing the same day. Larger ships are likely to spend the day at a single landing site.

The Ortelius — with a passenger capacity of 116 — was ideal for landings. But four days into our sail, landing was not yet our goal. The ice-chunked Weddell Sea had been deemed navigable by the captain and the Ortelius was determinedly crunching a path toward Snow Hill Island. We gazed from the deck at icy seas and distant snowy mountains, a tableau of immensity and isolation. With the closest ship and outpost a two-day sail away, we were truly alone in the world.

Yet that isolation felt eerily thrilling and profoundly Antarctica.

Comforts at sea

Antarctica-bound passengers will find themselves on an expedition ship, purpose-built for polar exploration. Ice-class ratings determine where a ship can go; ships with lower ratings won't venture among massive chunks of bobbing ice. A higher ice-class rating generally points to a richer itinerary.

Also, expedition ships are a different breed from cruise ships. Interiors are utilitarian, with carpets and walls that can withstand muddy boots, dripping parkas and odoriferous penguin guano. Some ships keep it bare-bones. Others offer cabin decor, upscale bars and alternative restaurants. Considering the amount of time spent on board, extra comforts may be worth considering.

The Ortelius is a seamanlike ship, with bland yet comfortable staterooms and a single pub-like lounge. It seemed a good match for our explorer-type voyage. Ortelius attracts adventurers, and I sailed with mountain climbers, filmmakers, photographers and a sizable group of young people. We hailed from 18 nations.

Despite brisk winds, we spent a lot of time on deck.

One day a lone emperor penguin appeared on an ice floe. He gazed at the passing ship, then dove from his miniature island to pop up alongside, drawing laughter and cheers with his acrobatic twirls.

We were certain he was our good luck sign, a greeter from the Snow Hill Colony.

Geography matters

Antarctic travelers are often puzzled over why ships dally among islands north of the Antarctic Peninsula, instead of steaming toward the continent. Yet wildlife abounds on the islands. I saw scurrying chinstrap penguins on the South Shetlands, plus numerous seals, sea birds, snowy peaks and passing whales. South Georgia Island boasts the additional draw of a graveyard where famed explorer Sir Ernest Shackleton lies buried.

Not only are the Antarctic islands the real deal, there's also the ice factor. The islands are generally more landing-friendly.

Passengers determined to set foot on Antarctica proper should consider an itinerary planning at least two or three landings on the peninsula.

The Antarctic Peninsula is rich with sites such as Brown Bluff, home to breeding grounds of Adélie and Gentoo penguins. Paradise Bay and Neko Harbor are known for impressive glaciers. Some ships sail the spectacular Lemaire Channel, a narrow passage between walls of ice. Travelers can mail postcards at the post office at Port Locknoy, a former British research station.

Playdate with penguins

On Day 5 aboard the Ortelius, the ship dropped anchor at Snow Hill Island on a balmy, sunny evening. Helicopter scouts had located the emperor colony 7 miles away; we were giddy with news that helicopter blades would start whirring at 5 a.m.

That night a snowy gale dashed our penguin dreams. The mood was glum; a little over a day remained to attempt to reach the colony.

But then it was playdate with penguins, despite gray skies. Our six-man helicopters lifted us over treacherous sea ice veined with deep crevasses, landing us at base camp. In groups of 25 we went photo-crazy watching the colony. Six-month-old fuzzy chicks batted wings at one another and tumbled over. Chicks waddled in cute imitation of a strutting 3-foot-tall parent.

A few adult penguins waddled over to study us. Although environmental regulations required us to stay 15 meters behind a red rope, the penguins were exempt. At one point I felt a tap, an expedition leader alerting me to a penguin staring over my shoulder, watching me shoot photos with student-like concentration.

Our penguin good fortune continued. The next day we basked in balmy sunshine on Half Moon Island in the South Shetlands, delighting in the little scurrying chinstrap penguins as they tumbled over and popped up again in new-fallen snow.

The sky was a bowl of blue deepened by glowing snow, and dozens of brave souls stripped to bathing suits for the "polar plunge," a traditional quick swim in icy waters.

Once again, though, the Antarctic magician of extremes came calling. Our homeward sail was smacked silly by one of the strongest sea storms. Sometimes the ship bucked so high, I sailed airborne to the bottom of my bed.

"Phenomenal storm," our taciturn Dutch captain said the next morning.

A phenomenal storm that added depth to my encounter with Antarctica, though "depth" was the term I adopted only after a week of watery nightmares disappeared.

Anne Chalfant is a former travel editor of the Contra Costa Times. She has written for Cruisecritic.com and newspapers around the country.