This Guy Rebuilt Russia’s Secret Abandoned Sea Monster

A new YouTube video shows a working copy of the “Caspian Sea Monster,” a unique high-speed seagoing vehicle developed by the Soviet Union in the 1980s. The “Monster” looks like a cross between a boat and an airplane, and functionally behaves a little bit like both. The Soviets designed the original—and much, much bigger—craft to take advantage of principles of air pressure to achieve near-airplane levels of speed over water.

In the 1970s and ’80s, engineers in the Soviet Union worked on several so-called “ground effect vehicles.” These vehicles had long, seaplane-like hulls; short, stubby wings to generate some (but not too much) lift; and one or more propellers or turbines engine for forward thrust. The vehicles create—and ride—a thin cushion of air between the vehicle and the ground, one that reduces drag and allows a vehicle to reach near-airplane speeds.

One of the most famous ground effect vehicles was the “Caspian Sea Monster,” or Ekranoplan KM. The craft was 300 feet long and flew from 1966 to 1980 across the Caspian Sea, until it was destroyed in a crash. Since the Soviet Union primarily conducted research into ground effect vehicles, studies were effectively halted once the country broke up in 1991.

YouTuber Peter Sripol impressively built his copy of the Ekranoplan KM out of glue, electric engines, and foam panels. Sripol seems to nail the principles, producing a working model that “flies” over ground and water.

The problem, as Sripol discovers, is that ground effect vehicles that use wings want to fly, a function of their lift-giving wings. Sripol constantly fights the craft’s urge to climb upward. It’s this problem that has made aviation companies hesitant to pursue the ground effect vehicle field, though at least one company in Russia proposed restarting production in the mid 2010s to service Arctic trade routes and bases.