NEW YORK (CBSNewYork) — The NYPD is gearing up for the city’s Fourth of July celebrations, and when fireworks are launched from the East River, the Harbor Unit will watch for potential trouble spots.

Most New Yorkers will be looking up during the Fourth of July fireworks, but the NYPD’s Harbor Unit has all eyes on the East River.

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“I call it our Super Bowl in the Harbor Unit,” said Lt. James Donnelly, with the scuba team.

“We prepare July 5 of last year until now,” said Anthony Russo, commanding officer of the NYPD Harbor Unit.

Before Macy’s even puts its 65,000 fireworks on a barge just off Red Hook, police scuba divers go in and inspect every inch.

“They go under the vessel and check for any anomalies, anything that could cause a problem, a bomb,” Donnelly told CBS2’s Ali Bauman.

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Once the fireworks are on the Macy’s barge, the Harbor Unit guards it by boat 24/7 right up until the show to make sure nobody tampers with the fireworks.

“I was out here guarding the fireworks barges, checking for any terrorist activity or anything like that,” Officer Joseph Villa said.

Thousands of people are expected to watch the show from the water on crowded commercial and private boats.

“If you look at a picture of the radar screen that night, all you see is dots of boats,” Russo said.

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The Harbor Unit acts as traffic agents and rescue teams.

“If you own a boat, everybody wants to come out on your boat to see the fireworks, so they pile more people on than usual,” Russo said. “One wake could capsize your boat.”

More than two dozen Harbor Unit boats, as well as two scuba boats, will be all-hands-on-deck Sunday.

“The current in the East River is strong. The boats will start to drift. They wont realize it unless you’re looking at land and you’re looking at two spots to sight where your boat was. You think you’re standing still, but you’re really moving at about 5 miles an hour, so it’s very easy to bump into another boat, especially in the dark,” Russo said.

“We’ve actually had to jump on or tow people out,” Donnelly said.

And when the show’s over…

“That’s actually the worst part for us because that’s when people are going back in the dark. If they don’t have radar, they don’t have GPS or they don’t know how to use it properly, that’s when its dangerous,” Russo said.

Even though it is hard work keeping the river safe…

“To be out on the water, the fireworks going off, all the people on land … it’s a nice night,” Villa said.

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The hard work pays off when those fireworks go off without a hitch.

Ali Bauman