That hovercraft caught invading a popular Russian beach last week wasn't just any old air-cushioned aquatic landing platform, it's the single biggest such vehicle in the entire Russian arsenal—or in any other military's, for that matter.
Simply put, the Zubr-class air-cushioned landing craft is the largest hovercraft on Earth. Originally designed during the waning days of the Cold War and built by Almaz Shipbuilding in St Petersburg, Zubr-class measure 187 feet long and 84 feet tall with just over a 5 foot ground clearance (draught). They're capable of transporting up the three main battle tanks (at 150 tons apiece), ten armored vehicles and 140 troops, 8 APCs, or as many as 500 troops, 555 tons of men and equipment altogether.
Designed specifically to sealift landing assault units on foreign shores, as well as lay mines in coastal waters, the Zubr-class employs high-temperature 100kW gas turbine engines to power a quartet of 18 foot-diameter, four-bladed variable-pitch air propellers and drive the vehicle to speeds up to 60 knots.
The 4,300 sq ft cargo area is trisected by two longitudinal bulkheads with armored vehicles travelling in the center compartment, the power plant occupying the rear, and troop quarters for the vessel's 31-man (4 officers, 27 enlisted) contingent taking up the front section. To keep sailors from going made with the constant hum that the fans produce, the crew quarters are heavily insulated against sound and vibration. The crew quarters can also be sealed against potential NBC (nuke, bio, chem) attacks as well.
Interestingly, the Zubr is also immune to the mines that it lays. Alloy armor and an active magnetic system cancel out not only the hull's magnetic field but also those generated by the mines stored on-board. Additionally, these hovercraft are equipped with electronic countermeasures and chaff decoy launchers. Offensively, the Zubr-class hovercraft are outfitted with a pair of stabilized rocket launchers, Strela-3 anti-aircraft missile launchers with heat-seeking supersonic (mach 1.5) rounds capable of homing in on a target 6 km away, multiple SA-N-5 "Grail" quad-launchers (like the ones from Commando), a concealed 140 mm Ogon rocket launcher with 132 unguided fragmentation/thermal rockets, and two AK-630 30mm autocannons that spew 3,000 rounds a minute at incoming enemy aircraft.
Unfortunately, the call for amphibious, D-Day style assaults on remote beach heads has waned significantly since the Zubr's initial deployment in 1988 and, as such, only nine vessels are currently active in the Russian, Ukranian, and Greek navies. [Wiki - Naval Tech - Almaz]