The One Fund's deputy administrator, Camille Biros, said many more claims were expected as the Saturday deadline approached.
"It's a busy day here," she said.
Three people were killed and more than 260 injured during the April 15 twin bombings near the marathon's finish line. The One Fund was quickly established by Boston Mayor Thomas Menino and Gov. Deval Patrick, and has grown to more than $47 million.
The fund is being administered by attorney Kenneth Feinberg, who has extensive experience handling similar compensation funds, including one established following the Sept. 11, 2001, terror attacks.
Feinberg set a deadline of Saturday for claims to be submitted, followed by a 10-day period when he'll interview potential recipients. He'll then make payment recommendations for review by the city, before money begins going out June 30.
The deadline comes as the trauma is still fresh and while some victims remain hospitalized for rehabilitation.
Bombing victim Pete DiMartino said last week he sent in the three-page application, which required letters from the two hospitals where he spent roughly 40 days combined after the attack. The 28-year-old bartender from Webster, N.Y., was hit with a significant amount of shrapnel and suffered burns and hearing loss. His right Achilles tendon was almost completely severed.
DiMartino said doing The One Fund application wasn't burdensome or traumatic.
"Not at all," he said. "I think that I was able to kind of talk everything out, as far as mentally goes. ... (The application) wasn't that much of a problem."
Carol Downing's daughter, Erika Brannock, lost most of her left leg in the bombings and remains at a rehabilitation hospital in Maryland. Downing said she worries that her daughter's condition could worsen after the money is given out.
"We still don't know that they're going to be able to salvage the one leg that she has, which would put her in a totally different category," said Downing, of Monkton, Md.
Downing added it was unsettling to read a doctor's letter she included in the application, which informed Feinberg that saving Erika's right leg was no guarantee.
"That was really the first time that sort of hit me that that could be a reality," she said.
The size of The One Fund awards will be based on the severity of an injury. Relatives of those who died, or victims with double amputations or permanent brain damage, will receive the most money. Next are those with single amputations, followed by those injured severely enough to require an overnight hospital stay. Those treated and released without an overnight stay are next.
Feinberg has warned that despite its impressive total, The One Fund won't be nearly large enough to fully compensate those who were hurt.
Downing said she appreciates whatever she gets and added she's under no illusion that even $1 million will cover her 29-year-old daughter's needs for the rest of her life. A single prosthesis for her daughter would cost about $75,000, she said, and requires replacement every five years or so.
DiMartino said he needs The One Fund money for continuing therapy and possible surgeries. He said he trusts Feinberg will be fair and isn't expecting a certain amount.
"It's not going to be something I worry about," he said. "It's just one more thing that's going to help me get back to where I was before all this happened."