Three days after Hurricane Sandy knocked out power to hundreds of thousands of Massachusetts residents, utilities remained confident that electricity would be restored to all but a few isolated households by early Friday.
Once power is back on locally, the companies plan to dispatch crews to areas that sustained severe devastation, including New York, New Jersey, Rhode Island, and Connecticut. One company, Unitil of Hampton, N.H., has already sent gas and electric crews to New Jersey and Rhode Island, according to a spokesman.
It’s not just the power companies stepping in to help the most ravaged areas get back on their feet. The Massachusetts Maritime Academy’s training ship, the T. S. Kennedy, is being sent to New York City to serve as a “no-frills hotel” for first responders helping the battered region recover.
About 6,000 National Grid and NStar customers remained without power Thursday evening, according to the Massachusetts Emergency Management Agency.
“The lion’s share of them will receive power by midnight [Thursday],” said Marcy Reed. president of National Grid, which had an estimated 5,600 customers without power Thursday afternoon.
Reed said some customers in remote areas, or the more challenging cases, could be restored by Friday morning. “Our first priority is to get the customers of Massachusetts restored,” she said.
All 172 communities served by National Grid were affected by Sandy, Reed said. At its peak, the company had more than 237,000 customers without power. As of Thursday, Worcester continued to have the largest number of outages, with over 400 out of 77,000 customers still without power.
“We’ve made significant progress,” Reed said.
Once the state is restored, Reed said the company plans to send crews to parts of southern Rhode Island and Long Island.
By late Thursday afternoon, NStar had restored power to the majority of the 400,000 customers who lost electricity, and expected to complete the job — about 6,000 customers — by Friday morning, said spokesman Michael Durand.
The majority of those still in the dark Thursday live in heavily forested communities such as Lincoln and Sudbury, where tree and wire damage was extensive, Durand said.
“There’s a lot of work that has to be done, and there’s considerable damage,” he said. “It could go beyond midnight [Thursday].”
Maureen G. Valente, Sudbury town manager, said NStar crews have been working hard to rebuild entire power infrastructures in the hardest-hit neighborhoods. But she said communications between the utility and town public-safety officials could have been better.
“There are some neighborhoods that literally look like a war zone,” Valente said of the town, which was visited Thursday by Thomas May, chief executive of NStar’s parent company, Northeast Utilities. “That has been a tremendous challenge, the number of trees and roadblocks.”
Once power is restored for NStar customers, crews will travel to Connecticut to help sister company Connecticut Light and Power.
Unitil, which by Wednesday had restored power to the 41,000 Massachusetts and New Hampshire customers, sent gas crews to New Jersey on Thursday, said spokesman Alec O’Meara. The company’s crews were on their way to Rhode Island Thursday afternoon.
In addition to extra utility crews, storm-ravaged New York will be getting the 540-foot Kennedy, built in 1967 and retrofitted to serve as a floating classroom in 2009. It can accommodate up to 710 people.
The federal government activated the Kennedy on Thursday to help with hurricane relief efforts, said Admiral Richard Gurnon, Mass. Maritime president. The Kennedy produces its own electricity and fresh water, which means it will not be a drain on strained resources where millions are without power.
“This will be a no-frills floating hotel,’’ Gurnon said. “It will be able to provide hot showers, light, safety, good food, and clean beds.’’
He said the vessel is expected to be used by first responders, utility workers, National Guardsmen, and others rushing into the region.
The vessel is owned by the US Maritime Administration, which used its authority to bring the ship into federal service, Gurnon said. The costs of the deployment and hotel costs will be paid for by the federal government.
Gurnon said he expects the Kennedy to sail from Bourne on Sunday and arrive in New York on Monday.
A crew of 30 academy personnel, including food-service workers, will be on board. He said he expects the deployment to last about a month.
“It’s a great opportunity for us to help and try to alleviate the suffering that has stricken New York and New Jersey,’’ Gurnon said.
Amid the push to aid other regions, the US Geological Survey is collecting storm-tide sensors that are spread out along the Atlantic Coast, including from Rhode Island to Plum Island. The gauges will help researchers understand the strength of storm surges caused by Sandy.
Preliminary data show that Sandy dumped 2½ to 4 inches of rain on the region, which is significant but not as dire as early forecasts predicted. Sensors placed on the Merrimack River in Newburyport, and the Pettaquamscutt River in Narragansett, R.I., indicated tides there were pushed 2 to 4 feet above normal high tide, Waite said. He expects the rest of the data to show similar results.
“When we find out, for instance, that the tide was 2 feet higher than normal, with that data and the high water mark data inland, we can create flood inundation maps that will show us how far the water went in,” Waite said. “We’re expecting to see that tides were 4 to 5 feet higher than the normal tides we see [along the coast].”Katheleen Conti can be reached at email@example.com. Follow her on Twitter @GlobeKConti.