The boat first appeared as a shadow on the horizon, blinking in and out of sight with the lilt of the Caribbean. It was the afternoon of July 13, and Kyle Humphrey, a seaman on the Coast Guard Cutter Gallatin, was nearly finished with his shift on lookout duty. Before leaving the flybridge, he had made one last sweep with the Big Eyes, a pair of mounted binoculars, and spotted the apparition in the wide-open blue.

Seaman Maria Soto, who had arrived to relieve Humphrey of his duty, got on the radio and relayed everything Humphrey was seeing. Whatever it was, the craft was a tiny one. The Gallatin was 80 miles from dry land, and it quickly became obvious that the little blue fishing boat they had spotted was hardly suited for high seas. With no engine and no sails, it was difficult to imagine how the 15-yard-long craft had gotten there in the first place. Some Gallatin crew members piled into a recovery boat and sped out to meet it.

Drawing nearer, Soto saw six people on the boat who later turned out to be from Jamaica. One of them was waving a white rag in the air.

Charles Miller, the second-in-command officer on the Gallatin, remembers watching as crew members lifted one of the passengers onto the deck of the cutter on a stretcher. The man was unconscious and severely dehydrated. The other three men and two women were alert, but they were not doing much better than he was.

“They had a fish they had somehow managed to catch,” Miller recalls, “and they were gnawing on its skull at that point.” During the 24 hours they spent in the hangar of the Coast Guard ship before being handed off to their own country’s military, the Jamaicans related a horrific tale: Pirates had stolen the onboard motor from their vessel, leaving them adrift for 30 days with no respite from the baking sun and no fresh water save for a bit of collected rain. One of the women had been pregnant when they left the Jamaican shore, and she had lost her baby at sea.

A few cruise ships had crossed their path, and the Jamaicans had lit fires to attract the cruise passengers’ attention, but to no avail. The odds against someone spotting a blue boat in the vastness of the Caribbean were astronomical. There were no radio distress calls, no blips on the radar. “It was pure blind-squirrel-finds-a-nut,” Miller says.

Talking about the rescue, Chief Stephen Dixon passes the credit along to the two lookouts, who hold the lowest rank among enlisted crew members.

“You need to talk to Soto and Humphrey,” he says. “Their eyes are what saved them.”

As the Gallatin spent the last two months docked in Charleston at the Federal Law Enforcement Training Center, its crew had time to swap stories like this one with friends and family, and even to brag to the crews of other Coast Guard ships. They also had a high-seas drug bust to tell the folks back home about, and of course there were the workaday tales of life in the utilitarian quarters of a relatively small seafaring vessel. On Friday, they headed back to sea.

 Summerville native Jake Bertram graduated from the Coast Guard Academy in New London, Conn., in May and joined the crew of the Gallatin as an ensign, an entry-level officer. Like many of the officers onboard, he talks about the Coast Guard’s humanitarian mission, which he says is a big part of the draw for some people. “They want to serve their country,” he says, “but not in an aggressive way.”

Clifton Lewis, who enlisted shortly after graduating from Stratford High School in Goose Creek in 2002, explains his career choice this way: “My dad is a cop, and my mom is a paramedic, so I figured this was the best of both worlds.”

Crew members on the Gallatin are eager to talk about the rescue, but let’s face it: If you join the Coast Guard and spend your time sailing between North and Central America, you’re going to end up busting some drug runners.

Capt. Caleb Corson, who took command just a day before the Gallatin picked up the stranded boaters, describes the mission of a Coast Guard cutter as similar to that of a beat cop. The Gallatin, a 378-foot ship with four diesel engines capable of pushing through the waves at up to 46 miles per hour, usually patrols the Caribbean alone for stretches of up to three months, its crew keeping a constant lookout for boaters in distress and suspected narcotics smugglers.

Corson sits at ease on a couch in the captain’s office, which is spartan but spacious by shipbuilding standards, and speaks with the untraceable accent of a man who has lived his whole life on the move.

“Home is wherever my hat is hung, and right now, that’s in Charleston,” he says. Corson’s father was an aviator in the Coast Guard, so Corson spent much of his early life in transition: Japan, Alaska, Hawaii, Connecticut, Massachusetts. He had planned to be a veterinarian, but eventually he followed in his father’s footsteps. Corson didn’t fall in love with the sea right away, but he loved the daily challenge of the work.

Under the previous captain’s watch, on July 5, the Gallatin notched a major victory when it stopped a vessel carrying 920 kilograms (over 2,000 pounds) of cocaine. In the end, the Coast Guard handed over the arrested crew of the ship, $25 million worth of contraband, and the ship itself — the Fifita 500 — to the Panama Express, a law-enforcement entity that includes members from the FBI, DEA, and ICE.

Netting a drug boat is sometimes more art than science, depending on chance encounters and informed hunches. Troy Matthews, a first-class petty officer on the Gallatin who lives in Summerville, has been running counter-narcotics operations on various ships since 1999, and he knows the telltale signs by now. When a ship approaches, a crew member gets on the radio to ask some basic questions: Where are you coming from? Where are you headed? What are you hauling?

“It’s pretty unusual to see a vessel in Central America going somewhere empty,” Matthews says. Even fishing vessels will often pick up cargo at every port to make some extra money, so when someone comes on the radio saying that his ship has nothing onboard, Matthews sees a red flag. In the case of the Fifita 500, the man on the radio ­— who claimed no nationality and spoke through the Gallatin’s Spanish-language interpreter — insisted that the ship was empty but was going to pick up a load of electronics at its next port of call. Matthews stood by as the interpreter spoke to the man for an hour and a half, and then he passed the information along to a command center in Virginia, where officials made the call to board the Fifita 500.

Five crew members armed themselves, piled into a smaller boat, and sidled up to the ship in question, climbing onboard without incident. Matthews says no one has ever opened fire on his men during a boarding, and this was no exception. The crew seemed unfamiliar with their own ship, which was dirty and poorly maintained. “We were expecting it to catch on fire at any moment,” Matthews says.

Gallatin crew members spent eight days aboard the ship, trading off in 12-hour shifts to search every nook and cranny while keeping an eye on its crew. Lewis, a maritime enforcement specialist, was on the second crew to board the ship. They swabbed an interior wall with a cloth and ran it through a device called an ion swipe machine, which detected traces of cocaine. Lewis remembers the painstaking process of measuring every dimension of the ship, mapping it out to find where any secret compartments could be.

Ultimately, what undid the crew of the Fifita 500 was its engineers’ refusal to recognize the existence of a third fuel tank. Lewis knew the ship had three tanks, but they insisted there were only two. A look in the third tank revealed the entire stash of cocaine, submerged in diesel fuel and broken up into 24 bales that were each wrapped in five to eight layers of rubber seals and packing tape.

 A major drug bust entitles a crew to some bragging rights in Coast Guard circles. Matthews chuckles as he remembers sticking the crew of the Dallas, another cutter that docks in Charleston, with the duty of towing the dilapidated Fifita 500 to Guantánamo Bay, Cuba, while the Gallatin brought in the real prize: the arrested crew and the ton of cocaine.

In other cases, the vessel itself can be a trophy. In the past decade, Matthews has seen the rise of self-propelled semisubmersible (SPSS) vessels, which drug cartels have begun custom-building for the purpose of stealthy passage to North America. Since the Gallatin is not equipped with sonar, and since an SPSS typically juts just a few feet out of the water, the vessels are a rare catch. Matthews says some of the ones he has seen are well-built, obviously produced by a major shipbuilding company. Others are veritable deathtraps, not much bigger or safer than the Civil War-era H.L. Hunley. To make matters worse, the small crews on these ships will often scuttle them when they realize they’ve been nabbed, sending the ship and its illicit cargo to the bottom of the sea.

Since Congress made the possession of semisubmersibles illegal in 2008, enforcement has gotten easier — video footage of people getting out of one of the vessels is enough for a conviction — but still, it is a point of pride to haul one of the peculiar ships to shore. At the Federal Law Enforcement Training Center, one such catch sits on a concrete stand by the road, serving as a training tool for boarding missions.

As for the Gallatin, there is some question as to how much longer it can sail alongside modern narco-subs and cargo ships. Built in New Orleans in 1968, it was meant to have a lifespan of 30 years and is now approaching its 43rd birthday. These days, it is losing more and more operational time to dockside maintenance and repairs. The Coast Guard plans to replace its remaining fleet of 10 aging cutters with bigger ships that require fewer crew members, but money needs to be set aside for that. The most recent cutter to get the green light will come at a cost of about $482 million.

On a recent training day in Charleston, Capt. Corson had a visit from congressional staffer Charles Kieffer on his itinerary. In the end, Kieffer couldn’t make it down from Washington, D.C., because of a vote in Congress, but he sent a Coast Guard officer to speak with the captain. “We need them on our side,” Corson says. “These ships are so old.”

The Gallatin left Charleston on Friday for another patrol of the Caribbean. The nearly 180 crew members were given few details about where they were headed, and they did not even have an end date to tell their families. Another three months, maybe. Another deep-sea rescue, another narcotics bust, another adventure on the ship they call home.