Ekranoplan: The True Story of the Caspian Sea Monster

For many, the term Caspian Sea Monster might evoke images of a mythical leviathan lurking beneath the waves. But in the annals of Cold War history, this monster was very real, and about as far as you can get from a creature of legend.

The ekranoplan, as it was technically called, was a colossal engineering marvel – a ground effect vehicle (GEV) that skated the boundary between sea and sky. Ground effect vehicles usually resemble a hybrid between an aircraft and a boat, and are designed to hover just a few metres above the ground.

Crafted by the Soviet Union during the height of the Cold War, the ekranoplan was a symbol of innovation, ambition and secrecy. This Russian flying ship was an answer to a complex challenge. How to rapidly move large payloads across vast distances, evading radar and enemy defences. The original, called KM, or Korabl Maket—model ship—was believed to have been the largest aircraft in the world when it was built in 1966.

Tales of this audacious vehicle, which became known as the ‘Caspian Sea Monster’, would circulate among Western intelligence circles, with many dismissing it as propaganda or exaggeration.

This is the true story of one of the twentieth century’s most remarkable vehicles.

A Ground Effect Vehicle is a craft designed to hover near the Earth’s surface by exploiting the aerodynamic effect which increases lift and reduces drag. Resembling a hybrid between an aircraft and a boat, GEVs are particularly efficient for low-altitude travel over flat terrains or calm waters.

As a GEV moves, it traps air between its wings and the surface, creating a cushion of compressed air that provides lift. This phenomenon, known as the ground effect, allows the vehicle to remain airborne while being more efficient than conventional aircraft at similar altitudes. Essentially, a GEV combines principles of both aircraft and hovercraft, enabling it to glide just above water or land at high speeds.

Literally ‘screen-plane’, the ekranoplan was a huge craft. It had a wingspan of 37.6 metres, it was 92 metres long and had a maximum take-off weight of almost 550 tonnes, yet it wasn’t a conventional plane. Powered by ten Dobrynin RD-7 turbojet engines, it was a GEV designed to fly between five and ten metres off the surface. In 1966 it took its maiden flight.

It’s believed the Korabl Maket had a maximum operational speed of over 300 mph. Some sources have even suggested it could travel at 460 mph, although these speeds were never verified.

This immense Russian flying ship was designed and built by a pioneering Soviet-era engineer called Rostislav Alexeyev. Its remarkable design allowed it to fly exceptionally low, primarily to avoid detection by enemy radar.

The discovery of the ekranoplan by the United States and its allies added a layer of mystery and intrigue to the Cold War’s already tense atmosphere.

Satellite reconnaissance was a primary method used by both superpowers to keep tabs on each other during the Cold War. While scanning the Caspian Sea area in the 1960s, U.S. intelligence satellites detected an unusual and massive object. With its enormous size and the Cyrillic abbreviation KM on its hull, the craft was quickly dubbed the Caspian Sea Monster by Western analysts.

Due to its location and the shroud of secrecy maintained by the Soviets, there was rampant speculation. Was it a new type of ship? An aircraft? Some kind of hybrid? The scale of the craft made it particularly puzzling, as its wingspan and length rivalled those of the biggest aeroplanes, yet its consistent presence near or on the water suggested something more akin to a boat.

Given the intense rivalry and arms race of the Cold War era, any unidentified development by one superpower was of urgent interest to the other. The U.S. and its allies made concerted efforts to determine the purpose and capability of the Russian flying ship and various theories were proposed.

Floating Airfield

Given its size, some believed it could serve as a kind of mobile airbase for Soviet operations.

Fast Troop Transport

The size of the Korabl Maket suggested it could carry a significant number of troops quickly, potentially deploying them in areas difficult for the U.S. to defend.

Missile Launch Platform

Due to the strategic importance of missiles in this era, some speculated it could be a mobile missile launcher.

It was only later, as more intelligence was gathered and defectors provided insights, that the West began to understand the principle of the ground effect and the true nature of the ekranoplan. The realisation it was a GEV was both a relief and a concern. Such a vehicle could bypass traditional naval defences, making it a potential threat, especially if used for rapid deployments or surprise attacks.

The Korabl Maket was continually tested for a number of years, as the vehicle’s capabilities were assessed. However, during one such test run in 1980, the pilot of the Korabl Maket mistakenly believed he was at a higher altitude than he was, and during a turn, one of the wings hit the water, causing the craft to crash. Thankfully, no one was killed, but the KM was damaged beyond repair and never rebuilt.

While the original ekranoplan was still being tested, Rostislav Alexeyev was busy designing a second version of the Caspian Sea Monster. The Lun-class ekranoplan, called Project 903.

While the 1960s craft was little more than a prototype, the Lun-class – Lun is Russian for ‘harrier’ – has the distinction of being the only GEV in history to have been deployed for military use, first by the Soviet Navy and then, as the Soviet Union collapsed in 1991, by the Russian Navy.

Two were planned but only one was built and it was slightly smaller than its predecessor. It was 73.8 metres long with a wingspan of 44 metres, and was powered by eight Kuznetsov NK-87 turbojet engines. It was reported to have had a top speed of 342 mph and a range of 1,200 miles.

Entering service in 1987, the next generation GEV bore a more overtly militaristic design compared to earlier ekranoplans. The most distinguishing feature of the Lun-class, apart from its size and presence, was the battery of six P-270 Moskit anti-ship missiles mounted prominently on its back. With these formidable weapons, it was intended for naval combat, primarily to patrol maritime borders and to target enemy vessels.
However, with the dissolution of the Soviet Union and the subsequent economic challenges, the ekranoplan program, including the Lun-class, faced setbacks and waning interest. The program was eventually cancelled.

After being retired for good in the late 1990s, this curious plane/boat hybrid sat in a naval base in the city of Kaspiysk on the Caspian Sea until 2020 when it was towed out of the naval base. It was destined for a military museum but became stuck in the sand close to its final resting place. Taking on salt water which was damaging the hull, it was pulled inshore in December 2021 where this relic of the Cold War era became an unusual, if not eerie, landmark, a testament to the ambitious vision of Soviet military innovation and its subsequent decline.

In the grand tapestry of Cold War intrigue, the mysterious Russian flying ship stands out as a symbol of both engineering ingenuity and the extremes of geopolitical competition.

The Caspian Sea Monster, as it was mysteriously labelled by Western intelligence, was not a creature of fable, but a tangible marvel of engineering that straddled the worlds of aviation and naval design. Its conception and development underline the Soviet Union’s pursuit of technological supremacy at sea.

Yet, like many ambitious projects of its time, the heyday of the Korabl Maket was fleeting. Economic challenges, changing military priorities, and the shifting tides of global politics consigned it to the annals of history. Today, as it sits silently on the shores of Dagestan, the ekranoplan serves as a poignant reminder of an era where superpowers fought to push the boundaries of physical and technical possibility.