YOKOHAMA, Japan — Quarantined for two weeks on a cruise ship ravaged by the novel coronavirus, the Britons on board have only one option: Keep calm and carry on.

David Abel and his wife, Sally, are still smiling, for now. Their friends Alan and Wendy Steele are going "stir crazy" trapped in their cabin — although they say they are not worried about catching the deadly illness. Still, this was not how the Steeles planned to spend their honeymoon.

Many of the 2,666 passengers and 1,045 crew members on the Diamond Princess are struggling to keep their spirits up after the luxury liner was quarantined off the Japanese coast Wednesday, with passengers forbidden to leave their cabins.

“We’ve got two weeks’ extra cruise, albeit a confined cruise,” David Abel, 74, said on a Skype call from his cabin. “You’ve got to make the best of the situation, haven’t you? But I’m sure that in 10 or 12 days’ time, I’ll be pulling my hair out.”

Last Saturday, a man from Hong Kong who had spent five days aboard the ship and disembarked was confirmed as having contracted the coronavirus. On Wednesday, with the ship docked at the port of Yokohama, Japan’s Health Ministry said nine other passengers and one Filipino crew member had tested positive. By early Thursday, the ship’s total confirmed cases rose to 20 after officials said 10 more people had tested positive, while 171 were awaiting test results.

The nine passengers who tested positive on Wednesday — two Australians, three from Japan, three from Hong Kong, and one American — have been transferred to hospitals, but none is in serious condition, said Japanese Health Minister Katsunobu Kato.

For those left on board, there is nothing to do but sit in their cabins, wait for meals to be delivered, watch television or choose from a limited selection of movies on demand. Those lucky enough to have a balcony can at least sit in the sun, look at the ocean and talk to their neighbors.

But you’re not getting anything really positive or encouraging talking to them,” Abel quipped. “It’s all doom and gloom as far as they’re concerned.

Abel said his greatest sympathy is with those confined to the inside cabins.

“Can you imagine? It would be liked being locked in a wardrobe, wouldn’t it?” he said. “No fresh air. No natural light. It really must be a living hell for them.”

Other passengers tweeting from the ship or talking to Japanese media showed the anxiety on board.

“Still shocked and scared. But better precautions. Have faith in the crews and captain,” tweeted Yardley Wong, who describes herself as a Christian entrepreneur from Hong Kong.

Life on board had been winding down Tuesday as medical staff went through the boat interviewing and testing passengers, with the casino closed and the evening’s main entertainment show canceled.

But guests still gathered for dinner, and smaller events continued where passengers mingled, hours before the captain ordered all passengers to go to their cabins and stay there.

A person with the Twitter handle @daxa_tw and tweeting in Japanese has been posting videos and photos of life on board the Diamond Princess.

“As for myself, I am going to assume that I have already been infected,” he tweeted.

In a direct message, he said he feared the number of infected people could grow significantly, “because this is a cruise whose main purpose is socializing.”

“Whether the quarantine was going on or not, it didn’t matter. Lots of events were offered. Dinner last night was just as it usually is,” he said. “I’m not worried. I just want to go home soon.”

Calls to room service go unanswered as crew members struggle to deliver basic meals. That means passengers cannot get an alcoholic drink.

Breakfast for many arrived about 11 a.m. — a problem for Abel, who has diabetes and needs to eat regularly to maintain his blood-sugar levels. Passengers had received just one cup of coffee by early afternoon.

On orders of Japan’s Health Ministry, they have been told they are not allowed to smoke, a problem for Wendy Steele, a 51-year-old nurse from Wolverhampton in Britain.

“That’s crucifying me,” she said.

The Steeles were married last month; the cruise around Asia was their honeymoon. Now, Wendy faces celebrating her 52nd birthday on Feb. 11 confined to her cabin. Alan, 58, was due to start a new job as a driver on Feb. 10, but his employer will have to wait.

For lunch, they were sent stale bread with ham, he said, a far cry from the meals that had been offered throughout the cruise.

“We’re basically being treated like we’re prisoners and criminals at the moment; that’s how we feel,” he said. “There’s nothing coming down the tannoy telling us when we’re going to be released onto the ship,” he added, referring to the public address system.

The pair said they were relying on the Internet and messages from fellow passengers to find out what was happening. They nevertheless stressed that the crew has been “amazing.”

Aside from going stir crazy, they said they were not worried about catching the virus, because they had socialized on board mainly with the Abels and an Irish couple, dining together every night, and none had fallen sick.

Negin Kamali, a public relations officer for Princess Cruise Lines, which is owned by British-American cruise operator Carnival, said the onboard guest experience team was working on developing “in-cabin activities and entertainment,” adding that the passengers will be allowed to leave the boat after 14 days.

David Abel, who has started a business in his retirement as a wedding celebrant, has been on about 20 cruises with his wife. He said they have three more lined up this year, when they plan to celebrate their 50th anniversary.

They are missing their family and their dogs, two Yorkshire terriers, back home in Northamptonshire. But this experience, he said, won’t put them off.

“We really love our cruises,” he said. This one, their first in Asia, took them to Vietnam, Taiwan and Hong Kong, as well as Japan. “I have really, really enjoyed the cruise. I would love to come back and spend another week or so in Taiwan.”

Akiko Kashiwagi contributed to this report.