The crew of the USS Underwood is waiting.

Somewhere amid the endless expanse of water that surrounds the U.S. Navy frigate, drug traffickers are speeding millions of dollars of contraband from Latin American shores to the U.S. The ship's mission is to stop at least some of that traffic, which from day to day means spending long hours searching the Western Hemisphere's coasts while preparing for action.

Endless duties and drills fill the day, as the crew trains for everything from a terrorist attack to a riot at port. At night, sailors sleep in tiny cubicles so cramped that many can't turn onto their sides.

A highlight of the six-month deployment is a special certification that requires getting shot in the face with pepper spray.

"This is very similar to being a small-time cop. Days or even weeks of nothing," said the ship's captain, Peter T. Mirisola, after a workout in the ship's makeshift gym.

Then, without warning, something happens. The crew sights a fast boat in nearby waters, and the frigate gives chase. Sometimes, the ship catches smugglers carrying drugs worth as much as $25 million on the street.

In October, the 30-year-old vessel was patrolling the Caribbean waters off Panama, as part of a multinational effort to hit illicit trafficking routes on both coasts of the Central American isthmus.

Since it set sail with a crew of 260 in April 2012, it's visited ports in Panama, Peru, Chile, Colombia, Jamaica, Trinidad and Tobago, the Netherland Antilles and Guantanamo Bay in Cuba. The Underwood is the oldest surface combatant ship in the U.S. Navy but no longer carries guided missiles. In fact, the recent deployment was the Underwood's last voyage, with 10 other U.S. Navy ships scheduled to be decommissioned early next year.

Life at sea is the only thing many sailors have known for years.

They receive three hot meals a day — Wednesdays mean hamburgers, Saturdays mean chicken wings and pizza. The crew can watch a baseball or football match on the armed forces network or catch a movie. They work out and even jog on the top deck, with the water and clouds stretching into the horizon.

There's a lot of time to think, about wives and children left behind in places such as Mayport, Florida, the Underwood's port.

Some seamen, such as Peruvian Navy 1st Lt. Paolo Camogliano, have left loved ones even farther away. The crew tried to make him feel at home one day by baking him a cake in the shape of Peru's red and white flag, in honor of Peruvian Navy Day.

One crew member, 3rd class petty officer Brian Stankowitz, had joined the Navy intending to deploy to Iraq or Afghanistan.

Leaning on the ship's railing as the Caribbean's waters rushed by, the tall, thin New Jersey native said he was doing his part to make the world safer.

"The Navy is a global force for good," he said.