Thundering along at incredible speed and obscured by a cloud of spray, it is easy to see why it was called the “Caspian Sea Monster”.
In fact, the massive machine was an ekranoplan, not quite a plane but not a ship either, and developed in the Soviet Union as a new form of transport.
Its full name was the Korabl-maket (KM) Lun-class ekranoplan, truly a monster at 92 metres long and weighing more than 500 tonnes. Had it been an aircraft it would have been the largest in the world when first tested in the 1960s.
Resurrected technology
The name ekranoplan in Russian translates as "screen glider". In English, such a craft is referred to as a ground-effect vehicle, based on the principle on which it worked, using the downwards thrust of air on water to lift it clear of the waves on a cushion of air, achieving speeds of up to 500 kph.
Abandoned as a project by 1980, the technology that underpinned the Caspian Sea Monster has been reborn with the Viceroy seaglider, built by an American company Regent Craft, who plan to use them in the waters around Abu Dhabi.
Regent has signed an MOU with the Abu Dhabi Investment Office (Adio) and Department of Municipalities and Transportation (DMT) to build passenger seagliders that would be used to connect the Emirate’s outlying island.
Using electric engines, they are a low-carbon alternative to aircraft and almost as fast. Regent hopes to be in business by the end of the decade.
Carrying up to 12 passengers, seagliders could travel between Abu Dhabi and Dubai in 30 minutes, with Adio’s director general, Badr Al Olama, predicting they will "shape the future of coastal transportation".
"With immense speed and efficiency, I’m confident Abu Dhabi will see the global deployment of electric seagliders and this will dramatically change how goods and people move between the world’s coastal areas going forward,” Mr Al Olama said.
Game-changing vessel
It’s a far cry from the project abandoned by the then Soviet Union in 1980.
Russian engineers began building ground effect vehicles in the early 1960s for potential military use. They used the cushion of air created by wings moving forward at speed, which was first noticed in early conventional aircraft when landing. While a problem for pilots, the Russian engineers realised this could also be used to great effect, lifting ships clear of the water, free of friction and drag, to reach very hight speeds and with huge payloads.
Their ekranoplan designs used stubby wings and multiple engines to provide the thrust needed to initially lift the craft out of the water to a height of barely three metres, at which point secondary engines would take over and propel it forwards.
For the Russians, this was a potential military game-changer. The ekranoplan flew low enough to evade radar but could not be detected by sonar like submarines or surface ships, while avoiding mines and anti-submarine nets. Effectively invisible, it could destroy enemy targets, including American aircraft carriers, at high speed.
Several prototypes were tested by the Soviet Central Hydrofoil Design Bureau, enthusiastically backed by then leader Nikita Khrushchev, who liked to boast that his country now had "ships that could jump over bridges", causing confusion among western military planners.
Around 30 versions of a 125 tonne ekranoplan were planned as a military transports planned for the Baltic and Black Sea, but the ultimate goal was the gigantic Korabl-maket, Russian for model ship, and completed in 1966.
At rest, the KM resembled a floating aircraft with foreshortened wings. Immediately behind the cockpit were two even shorter wings, each mounted with four Dobrynin RD-7 turbojet engines. Two more engines were mounted under its massive 37 metre tail, or stabiliser.
The eight forward engines provided the initial power and speed to lift the ekranoplan clear of the water. Once that had been achieved, they could be powered down, with the twin tail engines sufficient to propel it forward at a cruising speed of around 400 kph and with a range over 1,000 kilometres.
Designated as a ship, the ekranoplan was assigned to the Soviet navy, but operated by air force pilots.
A successful 50-minute maiden flight in August 1967 appeared to be a success. Its enormous size meant the KM was soon detected by a US spy satellite. American intelligence was baffled as to its purpose, but gave it the nickname “Caspian Sea Monster”, after the inland body of water where it was being tested and which is actually the world’s largest saline lake.
The KM’s limitations also became apparent. The craft could only safely fly when waves were less than a couple of metres, ruling out ocean deployment. The spray thrown up also caused saltwater corrosion in the engines.
Gradually the Soviet leadership lost interest in what seemed to be an expensive military white elephant. The end came in 1980 when pilot error caused the KM to crash and sink, although no lives were lost.
By then a second prototype had also been built, with six P-270 Moskit guided anti-ship missiles mounted on the top of the hull, and theoretically available both the Soviet Union, and after 1991, Russia. With only former Soviet republics and Iran bordering the Caspian Sea, its military value was questionable.
Relics on display
Three smaller A-90 Orlyonok or “eaglet” ekranoplan were also built, as transport and beach-landing craft but taken out of service in 1993 having never left the Caspian Sea.
One is now displayed at Moscow’s Navy Museum. Four years ago, the surviving second larger ekranoplan was pulled ashore in Dagestan for a new military museum and theme park in the city of Derbent.
But the demise of the ekranoplan did not spell the end for ground effect craft. Various companies and countries, from Iran to Germany, Singapore, and South Korea, have explored building new models with better technology.
Regent, a Boston-based start-up, seems likely to make them a familiar sight. Regent - an acronym of Regional Electric Ground Effect Nautical Transport - has obtained millions of dollars in funding to build and supply hundreds of seagliders all over the world and is now planning the next generation 100 seater Monarch - a true king compared to a monster, of the sea.
