July 11, 2013 -- A mother fought to keep her family alive as they clung to their capsized boat in cold water infested with jelly fish while her brother swam for five hours to get help.

Contessa L. Riggs, 43, of Washington D.C., was fishing off the coast of Deal Island, Md., on Tuesday with her brother, John Franklin Riggs, her 70-year old father, 9-year-old niece and 3-year-old son, when a thunder storm struck.

"It was sundown. The water suddenly became very choppy and a wave crashed into the boat, filling the boat with water," Riggs told ABC News.

Their boat was only 16 feet long and Riggs and her brother immediately knew they were in trouble.

"John started to bucket the water out and I grabbed life jackets and made sure everybody had one, but then there was another wave. In a second our boat was upside down in the water," Riggs said.

With their boat capsized, Riggs' brother and father swam under to get lifejackets.

"My father wears a pacemaker, and we had very young children with us, so we made sure everybody stayed near the boat," said Riggs.

"I had my son between me and the siding. John did the same thing for my niece," Riggs continued. "The children took turns sitting on the boat."

The family clung to the boat for an hour and a half in cold water infested by jellyfish and sea knettles.

"There was only a little bit of light left, and the storm was still in the distance. We could see the lightening hit the water and we knew there would not be another boat that late in the evening," Riggs explained.

"It was so cold. My son was shivering and shivering and shivering against me. He kept repeating 'I don't like this,' 'I don't like this,' 'This is no fun'," she remembered.

Riggs knew that nobody was going to start looking for them until the next day, so she and John decided they had to act.

"Our family wasn't expecting us back until tomorrow, and we didn't think we'd be able to make it that long," Riggs said.

"John and I looked at each other and he said, 'Should I try it?' I knew he was talking about swimming to shore. So I told him to try it. But we had no idea if he would make it to shore," she added.

The sun had set by the time Rigg's brother left his father, niece, nephew, and sister on the capsized boat. He swam for almost five hours, reaching shore around 1 a.m.

"John made it to the beach but he was so tired, he could not walk. So he crawled to the nearest house he saw. Luckily they had dogs, which woke the family up. And even luckier for us, that family had the personal number for the fire chief," Riggs said.

Meanwhile, Riggs and her family had been clinging to their rocking boat for almost eight hours.

"It was absolutely horrible," Riggs recalled. "Our legs were getting stung over and over again by the jellyfish. We had cuts and bruises. My son was crying. Waves kept crashing over our heads."

Riggs started to worry about her father.

"He had been in the water the longest. And I realized that if anything happened to him, I'd have to choose between helping him and leaving the kids and staying with the kids. It was such a hard choice to make peace with."

But Riggs found ways to keep everybody's spirits up.

"I kept saying, 'They're coming for us, we're going to get rescued, don't worry,'" she said. "We talked about stupid things like eating ice cream and watching movies."

It was as they were talking that Riggs noticed lights in the horizon.

"Suddenly we could see the boats and a helicopter and we just started screaming and waving."

Brother Swims Five Hours to Get Help for Family

Volunteer firefighters pulled Riggs and her family onto a boat but it was only until they were taken to a second boat that Riggs was reunited with her brother.

"It was the most amazing feeling. I ran up to John and said you are my hero."

The family is safely back on shore, with no significant injuries.

"Everybody is fine. But really, there were some very beautiful moments in the water. We were terrified, but the sky had never been clearer and we could see all the stars in the Milky Way. There was no light pollution," Riggs said. "The water was glowing blue with the flourescent jelly fish."

"I'm so grateful to the first responders that came and helped us out. I was so happy to see them and I love all of them. And I am so proud of my family, especially my brother. We survived together."

Friends and family are taking care of the survivors.

"Everybody has just been great," Riggs said.

"My friends have been cooking for us," she said, "They said I shouldn't have to worry about dinner after all of this. And I think they're right."

ABC News was unable to reach the Deal Island Volunteer Fire Department.