Such were the expectations for the navy hospital ship USNS Comfort that when it chugged into New York Harbour this week,throngs of people, momentarily forgetting the strictures of social distancing, crammed together along Manhattan’s west side to catch a glimpse.

On Thursday, though, the huge white vessel, which officials had promised would bring succor to a city on the brink, sat mostly empty, infuriating executives at local hospitals. The ship’s 1,000 beds are largely unused, its 1,200-member crew mostly idle.

Only 20 patients had been transferred to the ship, officials said, even as New York hospitals struggled to find space for the thousands infected with the coronavirus. Another Navy hospital ship, the USNS Mercy, docked in Los Angeles, has had a total of 15 patients, officials said.

“If I’m blunt about it, it’s a joke,” said Michael Dowling, the head of Northwell Health, New York’s largest hospital system. “Everyone can say, ‘Thank you for putting up these wonderful places and opening up these cavernous halls.’ But we’re in a crisis here, we’re in a battlefield.”

The Comfort was sent to New York to relieve pressure on city hospitals by treating people with ailments other than Covid-19, the illness caused by the coronavirus.

President Trump left a nine-day sequester in the White House last week to travel to Norfolk, Virginia, to personally see off the ship as it set sail for New York, saying it would play a “critical role”. The ship’s arrival on Monday was cheered as one of the few bright moments in a grim time for the city.

But the reality has been different. A tangle of military protocols and bureaucratic hurdles has prevented the Comfort from accepting many patients at all.

On top of its strict rules preventing people infected with the virus from coming on board, the navy is also refusing to treat a host of other conditions. Guidelines disseminated to hospitals included a list of 49 medical conditions that would exclude a patient from admittance to the ship.

Ambulances cannot take patients directly to the Comfort; they must first deliver patients to a city hospital for a lengthy evaluation — including a test for the virus — and then pick them up again for transport to the ship.

At a morning briefing on Thursday, officials said three patients had been moved to the Comfort. After The New York Times published an article with that number, Elizabeth Baker, a spokeswoman for the navy, said the number had increased to 20 by late in the day. “We’re bringing them on as fast as we can bring them on,” she said.

Hospital leaders said they were exasperated by the delays.

Dowling said he has had to tear his hospitals apart, retrofitting any unused space, including lobbies and conference rooms, into hospital wards. His facilities now house 2,800 so-called Covid patients, up from 100 on March 20, he said. About 25 per cent of those are in serious conditions in intensive care units.

Across the city, hospitals are overrun. Patients have died in hallways before they could even be hooked up to one of the few available ventilators in New York. Doctors and nurses, who have had to use the same protective gear again and again, are getting sick. So many people are dying that the city is running low on body bags.

At the same time, there is not a high volume of non-coronavirus patients. Because most New Yorkers have isolated themselves in their homes, there are fewer injuries from car accidents, gun shots and accidents that would require an emergency room visit.