The USNS Comfort docked Monday at Pier 90 on the West Side of Manhattan.
Hospitals will move non-coronavirus patients from Elmhurst to other locations.
Even though the comfort is not anticipated to treat Covid 19 patients, the ship is here to help as city reaches the height of the curve.
"Remember that before all this started, we had about 20,000 active hospital beds in New York City," Mayor Bill de Blasio said. "Depending on the trajectory of this crisis, we may need to turn all of those hospital-based beds into ICU beds. And use everything else for other types of needs - for hospitalizations that do not involve ICU, for COVID cases that do not involve ICU. That's what Javits will be about. That's what the Comfort will be about."
de Blasio said he's been working with the FDNY commissioner as they provide ambulances to move patients as well as respond to emergencies.
The Comfort, which was also sent to New York after the 9/11 terror attacks, has 12 operating rooms that could be up and running within 24 hours, officials said.
The ship is docked just north of a temporary hospital constructed inside the cavernous Jacob K. Javits Convention Center.
State and city officials are trying to increase hospital capacity by up to 87,000 beds to handle the outbreak.
"We bring a message to all New Yorkers - now, your Navy is returned and we are with you committed in this fight," said Rear Admiral John Mustin.
There are 9,500 people in New York currently hospitalized for COVID-19, with more than 2,300 in intensive care. More than 66,000 New Yorkers have tested positive for the virus.
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