Description (download PDF presentation)

High-speed amphibious cargo-passenger hovercraft Neptune 23GR (Nep23gp project) is designed for transporting up to 2.1 tons of cargo or up to 7 passengers + 1250 kg of cargo. Hovercraft belongs to the class of “cargo-passenger” hovercraft and is designed to transport both cargo and passengers across bodies of water in summer or winter, including with short-term access to the shore. The boat is capable of overcoming smoothed ledges up to 80 cm high and not smoothed ones — up to 55 cm. The boat is capable of reaching speeds on the water of up to 75 km/h.
Operation is permitted at outside air temperatures from -40ºS to +30ºS and a maximum wind speed of up to 12 m/s at any time of the year during daylight hours. Hovercraft, under all load cases, can be operated in water areas with waves of no more than 1.2 m 1% probability. The movement of the boat is allowed at the specified wave both in hovercraft mode and in displacement mode. When driving on ice or snowy surfaces, operation is permitted on bodies of water of all categories. Operation on any other flat, hard surface, extremely shallow water and swampy surfaces is permitted.

Main dimensions and characteristics

 

Housing

The hull of the vessel is made waterproof, divided into 7 waterproof compartments by 7 waterproof bulkheads.
Sheets and profiles made of aluminum alloys are used as the material for the main hull, frame, and foundations. Rolled sheets are used grade Amg5M, GOST 21631-76. Profile steel grade Amg6M or D16T according to GOST 8617-75. The hovercraft body is riveted (with the exception of small parts made by welding). The tightness of the outer contour of the boat and the corresponding transverse bulkheads is ensured. The impermeability test is carried out in accordance with the test diagram and table. Protection of the housing from corrosion is ensured by the use of aluminum-magnesium alloys that are resistant to corrosion in river and sea water. In marine hulls, D16 alloy is replaced with AMg. Additionally, it is planned to paint the outer and inner surfaces of the body with paints and varnishes.

 

Salon

During the production of the hovercraft, many different interior options were made. As a standard, the passenger cabin is equipped in the front with two soft passenger chairs, including one for the captain.
Six double lifting sofa-lockers are installed along the sides, under which life jackets and property are located. The sofa covers can be folded out to form a sleeping area measuring 1800×2000 mm in the aft part of the cabin. The arrangement of armchairs and sofas may vary. Options are available with soft seats for all passengers, with folding beds and a table, with a crane, with a toilet, with a loading platform and winches.
The cabin is made of a three-layer structure, the middle layer of which is insulation. The outer layer is made of fiberglass based on polyester resin with fiberglass reinforcing material, coated with colored resin (gelcoat). The middle layer is made of honeycomb filler. The inner layer is made of fiberglass, covered with lining — soft leatherette.

 

Cargo deck

A cargo deck measuring 4×4 m is installed on the hull of the vessel. The perimeter of the deck is fenced with a removable railing. The deck above the hull is covered with a removable awning to prevent transported goods from external influences. Deck material — aluminum-magnesium alloy sheets with anti-slip notches. To secure cargo on the deck, cargo clamps are provided. Upon request, it is possible to install various additional equipment and a loader crane on the deck.

Engine

The hovercraft is equipped with two Cummins ISF 2.8 engines, each with a power of 150 hp. It is possible to increase power to 175 hp. by increasing the maximum crankshaft speed.
Four-stroke, four-cylinder diesel engine with Common Rail electronic fuel supply system, with in-line cylinders and pistons rotating a common crankshaft, with an overhead camshaft. The engine has a closed-type liquid cooling system with forced circulation. Combined lubrication system: under pressure and splashing.
The Cummins 2.8 engine (Cummins ISF 2.8L) is installed on vehicles manufactured by GAZ OJSC, in particular on commercial vehicles of the GAZelle Business and GAZelle NEXT families. Due to its prevalence, the engine is well known to services, and spare parts and consumables for it are not expensive and can be easily found in stores. Today we can safely say that this engine is the most common commercial diesel engine in Russia.
The engine is equipped with devices to facilitate starting at low temperatures. To heat the air in the intake manifold, an electric spiral is provided. The fuel filter is also electrically heated.
The Cummins ISF 2.8 engine has very low fuel consumption.

The engines are standardly equipped with a turbocharger with an intercooler, that is, with pre-cooling of the air supplied to the charge. Thanks to the use of turbocharging, it was possible to provide high power and torque with a fairly small volume. At the same time, the presence of a turbine does not impair engine efficiency — its fuel consumption in a car ranges from 8.5 to 10.3 l/100 km, depending on the speed and operating mode.

The engine has a traditional design. It is based on a one-piece cylinder block (made of gray cast iron) and a cast head; the block uses insert milled liners, which facilitates cylinder repair. The crankshaft is also made of gray cast iron and is integral with the crankshaft position sensor pulley and toothed disk.

There is one camshaft, located in the upper part. The engine has 16 valves (4 per cylinder), made of heat-resistant steel, their rods are additionally chrome-plated. The valve drive is traditional, via rocker arms. Interestingly, all valves have the same design, but are not interchangeable. The timing drive is chain.

The engine is equipped with Common Rail fuel equipment from Bosch; the fuel injectors are top-mounted and installed in the central part of the cylinder. This solution significantly simplified the engine without significantly compromising its performance characteristics. In general, the Cummins ISF 2.8 is a simple, reliable and unpretentious engine that has good performance and is suitable for operation in Russian conditions. Thanks to design features, a simple design and the use of time-tested solutions, it was possible to achieve a long service life — the manufacturer claims an engine life of up to 500 thousand km (for a car), but in practice, the engine can last longer with proper operation and maintenance.

The engine is currently manufactured at Cummins’ FOTON joint venture in China.