RU2347694C2 - Air-cushion vehicle - Google Patents

Abstract

FIELD: transport, ship building.

SUBSTANCE: air-cushion vehicle incorporates a shell with skegs and is provided with outboard motors, supercharger with air ducts to feed higher-pressure air into the cushion. The proposed air-cushion vehicle features the M-shape cross-section of plating constricting the air-cushion space. The plating of the skeg inner sides, adjoining parts of bottom and pitching section of the bottom are smoothly mated. The clearance in diametrical plane makes at least 1/20 of the width between the lower edges of skegs. The aforesaid air ducts are recommended to be arranged along and outside the vehicles sides. The proposed invention allows reducing the air-cushion vehicle draught to mount standard outboard motors behind the propulsive unit transom.

EFFECT: improved performances, better comfort, enlarged shell payload volume due to arranging air ducts outside vehicle sides.

2 cl, 1 dwg

Description

The invention relates to shipbuilding and can be used in the design of skeg type hovercraft.

Known skeg vessel with an M-shaped bottom, according to patent PR 2665680 A, IPC B60V 3/06, comprising a hull with side skegs.

The disadvantages of the known solution include the small volume of the air cushion at a low height of the skegs and the presence of a flat-keel section of the bottom that together limit seaworthiness, and, accordingly, the use of ships by this decision only with the conditions of inland water bodies and the absence of pronounced excitement. In turn, the use of skegs of higher heights on small vessels for a wider range of sailing conditions is associated with difficulties in using outboard motors with standard deadwood lengths, the distance between the anti-cavitation plate, usually located at the lower point of the bottom of the vessel and the power unit, which should be located higher the waterline of the ship in the parking lot. This is because the width and volume of the skegs are usually small, the shape of the cavity under the hull containing high pressure air, an air cushion, as a rule, U-shaped in cross section, and draft of the vessel is large compared to the standard lengths of deadwoods of outboard motors. Placing the supercharger in the stern, behind the boat transom, causes an additional increase in the draft of the stern of the boat afloat and the immersion of the power unit of the outboard motor. In addition, in practice, the bulk of the high pressure air supplied to the air bag cavity under the ship’s hull is supplied through the pneumatic design of the bow flexible guard and directly in the middle part of the ship, and only a small part into the stern flexible guard. Therefore, the air ducts from the supercharger should be drawn into the middle and bow of the vessel. The placement of air ducts inside the hull of the boat occupies a useful volume and reduces the comfort of the vessel, restricts the space for passengers and cargo.

The technical result of the proposed solution is to provide the possibility of using outboard motors on small vessels with improved seaworthiness. Namely, achieving a draft of a skeg-type hovercraft afloat, allowing the installation of propulsion modules on the basis of standard outboard motors behind the transom, which improves the technological quality and ease of use, as well as improving passenger comfort and increasing the useful volume of the hull by removing the air ducts from the internal hull space on the outer sides while maintaining other positive qualities of the vessel.

The problem is achieved in that in an hovercraft with a hull with skegs and equipped with outboard motors, blowers with air ducts for supplying high pressure air to the cavity under the hull, a keeled section is formed in the center of the bottom between the skegs, and the clearance in the diametrical plane is not less than 1/20 of the width between the lower edges of the skegs, and the sheathing of the inner sides of the skegs, together with the adjacent sections of the bottom sheathing, are made in the section arcuate and inclined to the diameter noy ship plane and the air ducts are placed along the boards outside.

Thus, a keeled section is formed in the central part of the bottom, and the cross-sectional shape of the lining of the cavity containing high pressure air, the air cushion, is converted from a U-shaped to an M-shaped.

The degree of increase in the volume of skegs and keeled area in the central part of the bottom in each case can be determined from the necessary reduction in draft of the vessel for the use of specific standard outboard motors.

Compliance with a clearance of at least 1/20 of the distance between the lower edges of the skegs is necessary to effectively reduce the resistance to movement on an air cushion.

Ducts are made of airtight materials with a textile or other flexible base, flexible and quick-detachable, including wear-resistant materials.

The achievement of the technical result, the possibility of using outboard motors on skeg type hovercraft is achieved by increasing the joint displacement of the skegs and the central section of the bottom.

The draft of the vessel afloat, without a move, is reduced. The volume of the air cushion decreases upward, and the volume of the skegs and the body increases upward.

In addition, the following technical advantages are shown that provide the claimed technical solutions with significant differences.

The ship's sailing comfort is increased by reducing the amplitude of vertical rolling and more successful damping of wave overloads, since the air pressure in the pillow and hydrostatic lifting force increase intensively when the water surface is supported from below and due to the wedge effect when the central keeled section of the bottom contacts the water.

The seaworthiness of the vessel is increased due to faster compensation of the reduced volume of air in the air bag cavity when it is lost in waves. During the course without excitement, the operation efficiency of the vessel is increased, since a decrease in the volume of the cavity under the hull allows to proportionally reduce the air flow into the pillow.

The useful volume of the hull also increases due to an increase in the volume of skegs and the possibility of placing components of equipment and payloads in them.

The strength of the hull is increased by reducing spans, increasing the degree of embedment and increasing the moment of inertia in the dangerous central sections of the transverse links of the hull, frames.

The plating of the inner sides of the skegs, adjacent sections of the bottom and the central keeled section of the bottom smoothly conjugated further enhances the damping of overloads when driving on a wave, as well as the general and local strength of the hull, due to the shape effect of the shell. It also helps to reduce stress concentration in the transverse connections of the housing and to reduce the mass of the skin.

Placing ducts outside the enclosure frees up internal usable volumes. Additionally, due to their peripheral location and increased pressure, they play the role of a jacking device, protect and shield the upper, inhabited part of the vessel from splashes, while providing increased safety. The implementation of flexible ducts allows you to save the size of the vessel without running in the parking lot, during transportation or storage.

The implementation of the proposed solutions does not require the involvement of additional technological equipment and other production equipment, and also allows you to apply the modular method of installing a power plant, including outboard motors, and air distribution systems of high pressure vessels. Designs for attaching elastic materials to the body are widely known and available. Elastic ducts outside the sides of the ship also have the advantage of being repairable afloat and easily replaceable.

The technical solution for increasing the volume of skegs and the use of a prismatic section in the central part of the bottom to regulate draft and soften the course on waves has a novelty with respect to skeg type hovercraft.

The drawing shows a cross-section of a skeg type hovercraft, on which the proposed solution is most clearly shown with the outboard motor circuit on its background. The vessel contains a hull 1, made with an M-shaped cross-sectional shape of the casing bounding the cavity of the air cushion 3, with skegs 2 and equipped with outboard 8 motors, blowers with air ducts 10 for supplying high pressure air to the cavity under the hull, which is lining the inner sides of the skegs 2 , adjacent sections of the bottom and keeled section 7 in the central part of the bottom are smoothly conjugated, and the clearance in the diametrical plane is at least 1/20 of the width between the lower edges of the skegs.

Outboard motors 8 are placed behind the transom, behind the skegs, in the normal position, with the power unit above the waterline afloat 9. Flexible ducts 10 are placed along the sides from the outside of the vessel.

The proposed design works as follows. The inclination to the diametrical plane 5 of the inner sides 4 of the skegs 2, made arcuate, smoothly interfaced with the adjacent sections of the bottom 6 and the keeled section 7, increases the volume of the skegs 2 in their upper part, as well as the submerged volume as a whole, and helps to reduce float, providing the position of the power unit of the outboard motor 8 is higher than the water line 9. The extension of the skegs 2 in the upper part allows to place part of the components of the ship’s equipment or payload in them. The volume of the cavity of the air cushion 3 decreases upward, which, with water backwater, contributes to an intensive increase in air pressure and a decrease in vertical displacements, a decrease in the amplitude of the vertical pitching along with more effective damping of vertical accelerations and counteraction to a rise in the water level inside the air cushion cavity. The decrease in the volume of the cavity of the air cushion 3 under the bottom also contributes to the fastest filling with air from the supercharger and provides an accelerated increase in air pressure during the passage of the crests of the wave.

When the water surface touches the lower point of the keel section 7 in the central part of the bottom on a wave or when air is lost from the cavity of the air cushion 3, the vertical accelerations are reduced due to the concentration of excess pressure air in the two cavities formed under the vessel’s hull 1 and the wedge effect. Smooth conjugation of the sheathing of the inner sides of the 4 skegs 2 with the adjacent sections of the bottom 6 and the sheathing of the keel section 7 can increase the degree of closure of the transverse connections of the hull and reduce the stress concentration in them, increase the moments of inertia in a dangerous section in the region of the diametrical plane 5.

Air ducts 10 do not take up space in building 1, are available for monitoring, repair and replacement both in the parking lot and in the water area. They protrude outward in relation to the hull 1 and shield the splashes that occur during the course of the vessel, and serve as an additional energy-intensive fencing device. Elements of air ducts supplying air to the cavity 3 are not shown.

Claims (2)

1. The hovercraft, including a hull with skegs and equipped with outboard motors, blowers with air ducts for supplying high pressure air to the cavity under the hull, and also made with an M-shaped cross-section of the casing, limiting the cavity of the air cushion, characterized in that the skins of the inner sides of the skegs, adjacent sections of the bottom and the keel section in the central part of the bottom are smoothly conjugated, and the clearance in the diametrical plane is at least 1/20 of the width between the lower edges of the skeg in. 2. The hovercraft according to claim 1, characterized in that the ducts are located along the sides from the outside.