Moving at the speed of flip-flops, we walked the third-of-a-mile from the ferry dock to the beach at West Ship Island in about 10 minutes. Before that, we cruised across a dozen calm miles of the Mississippi Sound in about an hour. The drive my wife and I made from our New Orleans home to the ferry’s departure point in Gulfport, Mississippi, earlier that morning took an hour and change.

But when we finally splashed down in the water off this tiny barrier island, with a vista of blue sea and sky ahead and a startlingly clear view of our toes and the swirl of small fish just below, it seemed that we had trekked much farther. In the ledger of exertion to enjoyment that goes into any getaway, we had just tallied a real bargain.

Heading to the beach is all about fun and relaxation, but in southeast Louisiana these trips always have to start with some hard math. Sure, the beaches begin almost as soon as you cross into Mississippi, but the really celebrated stretches of the Gulf Coast, with crystalline water and Central Casting white sand, are several hours farther along. So beach trip planning inevitably brings up calculations of travel time and trip budgets. The tradeoff for proximity is usually brownish waters.

One reason I like visiting West Ship Island is the way it takes this linear, west-to-east equation and bends it south — 12 miles south to be precise. This simple action reframes the reckoning of time and distance, putting an immaculate beach ringed by successive bands of aquamarine and deep blue waters much closer to home, while the island setting adds the easygoing adventure of a short sea journey and the prospect of exploring a historic fort to the deal.

An offshore beach

You can’t see West Ship Island from shore, but find it on a map and it’s easy to see how it fits within the patterns of the larger Gulf Coast region. It’s part of a string of narrow barrier islands stretching from Mississippi to Florida that buffer the coast and serve as wildlife havens, delicate outposts teeming with birds and marine life, their sandy contours stitched together by the roots of sea oats and reshaped regularly by major storms. Indeed, Hurricane Camille split what had been one island into West Ship Island and East Ship Island in 1969.

For day trippers, West Ship Island functions as an offshore beach, an over-the-horizon oasis accessed only by private boat or ferry service from Ship Island Excursions, a company that has been shuttling people to the barrier islands since 1926.

The entire island is administered by the National Park Service as part of its Gulf Islands National Seashore. Development is contained to a narrow corridor running between the ferry dock to the Gulf-side beach across the island, with bathrooms and picnic pavilions and a snack bar for burgers, cold drinks and beach sundries in between. A sturdy boardwalk connects it all, and also offers a cross-section tour of the island’s landscape, which changes from wind-tussled salt marsh to wavy, shrub-covered swales to dune and open beach within the span of a short walk.

Natural beauty abounds, though West Ship Island doesn’t necessarily feel secluded. The arrival of each ferry augurs a little rush hour at the dock, with a few hundred people disembarking at once. Practically everyone marches directly toward the Gulf side beach, and a fresh tide of people sweeps in every few hours.

It’s easy enough to find your own space, though most people tend to stick by the cluster of facilities for the singularly compelling reason that this is the only area to find shade. Like the deck of a ship out in the summer sun, the beach here can be searing hot, and the umbrellas provided by the on-island concessionaires become a precious commodity.

The one dominant man-made feature here, Fort Massachusetts, can be pressed into duty for this purpose too. Built by the army between 1859 and 1873, it was once part of a national system of coastal defenses and now stands as a monument to a bygone era of American history.

Designed for warfare, today the stronghold seems elaborately baroque. Its brick walls curve into a fat horseshoe bend of arches and apertures, with slabs of stone splayed into spiral staircases leading to close passages and vaulted corridors. Geometric patterns of granite, brick and iron trace the network of old gun emplacements while the parapet above is now a long grassy mound, kicking up tall grasses and small flowers like a rooftop meadow.

Park rangers give free tours of the fort and share stories from the island’s history as a military installation. A self-guided tour serves just as well for a dose of shade in the fort’s dark, sometimes dank, chambers and, given its setting on a desert island it’s easy to conjure Robinson Crusoe-like imagery around this impressive structure.

But any trip to West Ship Island is built around the beach and fun in the sun. We joined a tide of people wading slowly into the warm water, where kids splashed around and parents pointed out the variety of fish and occasional scuttling crab so clearly visible in the near-transparent water. By the time the water reached our chests it was cooler and we floated around in the buoyant salinity, with the sounds of beach day frolicking carrying across the low ripples. Back on the beach, there was the prospect of simply sitting under an umbrella and absorbing the passive therapy of time spent gazing out across white sand and variegated shades of blue.

A roundtrip recharge

Despite the cold, hard appraisal of time, distance and destination that goes into a day trip, the ferry ride to West Ship Island does not count as getting there, at least not to me. As soon as the boat whistle sounds and the vessel pulls away from the dock the adventure has begun, and it continues on the return leg too.

We found a seat on the shaded, open-sided upper deck and watched as the red brick, white sand and green center of the island diminished and the rest of the Mississippi Sound opened up.

Seabirds followed the ferry, drafting behind the stern and swooping and diving as if playing some game with each other, and the dark dorsal arches of dolphins crested through the water from time to time. On board, the sun-kissed, sand-pocked passengers sunk into their own little cocoons of terrycloth and cover-ups as the last chapter of the outing unfolded.

Follow Ian McNulty on Twitter @IanMcNultyNOLA.