“There are no freak waves in the world,” says naval architect Jon Etxegoien. “They are all predictable.”

He’s strolling the shores of an indoor ocean—a 12-million-gallon, football-field-size pool at the Naval Surface Warfare Center in the Maryland suburbs of Washington, D.C. A two-star admiral in crisp khaki leans on the railing nearby, watching obedient waves plunge and leap like show dolphins.

The recent installation of 216 state-of-the-art electronically-controlled wave boards has made this the most sophisticated scientific wave-testing basin of its size in the world. Scaled-down fiberglass models, cruisers the size of canoes, ride waves that max out at a few feet high. But it’s the motion of the ocean that matters. The hinged wave boards, each with its own motor synced up to software, can precisely recreate eight ocean conditions (from flat calm to typhoonlike) across all seven seas, pushing the water and moving up and down like giant piano keys whose scales and chords are waves.

New technology can precisely recreate eight open-water conditions

The Navy tests models in the basin to be sure that billion-dollar ships will float before it builds them, but also to assess whether sailors can launch missiles and land helicopters in particular circumstances, and how vessels handle with a full tank versus running on fumes. Pitch, roll, sway, heave, acceleration, displacement—the calculations alone are enough to make you queasy.

A relic from the 1960s, the old pneumatic-powered wave system couldn’t replicate complicated open-ocean conditions, which are driven by local winds and far-off hurricanes. The testing team sometimes had to take remote-control models to the actual ocean, scouring weather reports for the perfect chop. Other seafarers have mistaken the models for “Cuban drug-smuggling submarines,” says test director Calvin Krishen. “We hear about it in the bars afterward.”

Salty stories aside, the excursions were not efficient. Simulations in the newly improved freshwater pool (the difference in density between it and saltwater is mathematically accounted for) can cover in six weeks scenarios that took many months of voyaging to recreate. Recently, the Navy tested a missile submarine slated to become operational in 2031. Other tests are classified.

The high-seas realism is unparalleled—unless, of course, the wave makers program the waves to be exactly parallel, which doesn’t happen at sea. Similar technologies have even fashioned waves that look like alphabet letters. “It almost becomes a kind of art,” Etxegoien says. “But our challenge is to do what nature can do, not what it can’t.”

Right now the pool is churned with what’s called a JONSWAP, a spectrum of specific frequencies and wavelengths derived from North Sea conditions. Fluorescent orange deer nets line the concrete beach, should a model destroyer ever run aground—though today there are no vessels under way, so the water troubles only itself.

The control center is a glass box high above the spray. But rather than Captain Nemo at his pipe organ, or Neptune himself, there’s a young man in a backward Orioles cap sitting in front of a computer, cranking out preprogrammed waves. Whether the scientists request ripples or hundred-year-swells, says Tony Lopez, an electrical engineering technician, “I just press a button that says start.”