Stabilized Hull of a Monohull Motor Boat, Which Surfs an a Water Cushion and has a Deeply Submerged Supporting Blade

Abstract

The invention is related to boatbuilding and may be used in construction and modernisation of high-speed monohull motor seagoing boats, where a single hull is used, which is moving in a surfing on a water cushion mode.

Stabilised hull of a monohull motor boat, which is using a surfing glide on a water cushion, with the deeply submerged displacement bearing blade, with a hull of a total width of not more than 50% of its length, which, in its lower part over its entire length, has a descending shape of its bottom surface in the direction bow-to-stern, where the bow is elevated up to the distance from the waterline, corresponding to at least 25% of the hull's width, and under the bow is a high wave-piercing stem. Wherein, in the front 40% of the hull's length, the bottom surface has a descending shape, which smoothly flows into the bottom surface of the stern part of the hull, and has an angle of descent in relation to the waterline at zero speed of at least 5 degrees, in the rear 60% of the hull's length, the bottom surface has a descending shape, and the angle of descent in relation to the waterline at zero speed of not more than 5 degrees, while it has an almost flat shape in its cross section, and is submerged by 70% or more of its length below the waterline, where the submerged part becomes the “surfing surface”, which is gliding, during the boat's movement, on a water cushion, and carrying not more than 70% of the boat's fully loaded weight.

The hull is made with a longitudinally positioned located underneath the bottom surface, symmetrical with respect to the boat's centerline, and commensurate with its length, vertically oriented, deeply submerged displacement bearing blade of narrow shape and of low wave/hydrodynamic resistance; wherein the ratio of the length to the width of the bearing blade of at least 20 times, with the displacement of the bearing blade corresponding to 30-50% of the boat's fully loaded weight, and with its height (excluding the stem) of not less than 20% of the maximum width of the hull, wherein ensuring a deep submersion of the bottom edge of the bearing blade in relation to the waterline. The bearing blade is made with wave-piercing lines, with a high wave-piercing stem, reaching by its height the bow end of the bottom surface of the hull, with the sharp rear and front lines, and the smooth middle lines; and has a triangular cross section over its entire length, with the most acute angle at its bottom; and the maximum width of the bearing blade is located within 40-60% of its length, which determines the centre of the displacement of the bearing blade within 40-60% of its length, in its upper third.

The controllable hull of the displacement boat stabilised for sea waves conditions and gliding on the water cushion, opens up broad prospects for the construction of the high-speed seagoing boats. First of all, this is a fundamental improvement in stability of the movement, and the absence of rolling/pitching and yawing in the open Sea, as well as increase in a carrying freight capacity and improvement in the fuel economy, as compared to the planing hulls.

1 independent item of formula. 1 dependent item of formula. 15 illustrations.

Claims

1. Stabilised hull of a monohull motor boat, which is using surfing glide on a water cushion, with a deeply submerged displacement bearing blade, characterised by the total width of the hull of not more than 50% of its length, which in its lower part: has over its entire length, a descending shape of its bottom surface in the direction bow-to-stern, wherein, the bow end of the bottom surface is elevated to the distance from the waterline, corresponding to at least 25% of the width of the hull; where there is a high wave-piercing stem located under the bow end of the bottom surface, wherein, in the front 40% of the length of the hull, the bottom surface has a descending shape, smoothly flowing into the bottom surface of the stern part of the hull, and has the angle of descent of at least 5 degrees, in relation to the waterline at zero speed, wherein, in the rear 60% of the length of the hull, the bottom surface has a descending shape, and has the angle of descent in relation to the waterline at zero speed, of not more than 5 degrees, wherein it has nearly flat shape in its cross section and is submerged by 70% or more of its length below the waterline as counting from the stern, where the submerged part becomes the “surfing surface”, which is gliding during the boat's run, on the water cushion, and carrying no more than 70% of the boat's fully loaded weight, wherein, the hull is made with a longitudinally positioned located underneath its bottom surface, symmetrical in relation to the boats' centerline and commensurate with its length, vertically oriented deeply submerged displacement bearing blade of narrow shape and of low wave/hydrodynamic resistance, wherein, the ratio of the length to the width of the bearing blade is at least 20 times, with the displacement of the bearing blade corresponding to 30-50% of the boat's fully loaded weight, and with the height (excluding the stem) of not less than 20% of the maximum width of the hull, wherein ensuring a deep submersion of the bottom edge of the bearing blade in relation to the waterline, wherein, the bearing blade is made with the wave-piercing lines, a high wave-piercing stem, which by its height is reaching the bow end of the bottom surface of the hull, with the sharp rear and front lines, and smooth lines in the middle, wherein, the bearing blade, over its entire length, has a triangular shape in its cross section, with the most acute angle at its bottom; and the maximum width of the bearing blade is located within 40-60% of its length, which determines the centre of the displacement of the bearing blade within 40-60% of its length, in its upper third.

2. The hull of the monohull motor boat according to item 1, different in that on at least 30% of its length or more, as counting from the stern, at the maximum width of the hull, there are positioned vertically oriented and symmetrical to the boat's centerline, thin longitudinal plates limiting the water flow, with their submersion below the waterline at the distance corresponding to at least 2.5% of the hull's width.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Claimed materials are provided in the following graphic illustrations. A general view of the hull is shown on FIG. 1, various spatial views of the hull are shown on FIGS. 1.1-1.7.

[0086] FIG. 1. A general view shows the hull 1, including the bottom surface 2, and the deeply submerged bearing blade 3. The lower surface 2 has a descending shape in the direction of the bow-to-stern, along the entire length of the hull. As a result of support from the displacement bearing blade 3, the bow end of the bottom surface 2 is raised above the waterline of the boat, to the level of elevation of “SE”, constituting not less than 25% of the maximum width of the hull “HW”. Under the bottom surface raised in the bow there is a high narrow stem 4 extending into the upper part of the bearing blade 3. The bottom surface 2 in the stern part of the hull is almost flat.

[0087] The bearing blade 3 has its height “BH” (not including the stem), “BH” is not less than 20% of the hull's width “HW”, while the ratio of the length of the blade “BL” to the maximum blade width “BW” is not less than 20 times. The maximum width of the blade is in the middle of the length of the bearing blade (variants of 40-60% of the length are possible). The bearing blade has a triangular shape in the cross section along its entire length, with the most acute angle being at the bottom. Thus, the blade displacement centre is in the middle of its length, in the upper third. The bearing blade displaces an equivalent weight of 30-50% of the boat's fully loaded weight, that is, the bottom surface of the hull carries 50-70% of the boat's weight. Reducing the weight of the boat per unit area of the surfing surface contributes to creating and maintaining the laminar continuous [water] flow inside the water cushions.

[0088] In the front 40% of the hull's length, the descent of the bottom surface forms an angle in relation to the waterline at zero speed “Ang1” not less than 5 degrees, thus forming the squeezing surface impacting the water flow; and in the rear 60% of the length of the hull “Ang2” of no more than 5 degrees, wherein in the rear 60% of the length of the hull, the bottom surface has an almost flat shape in its cross section, thus forming the hull's surfing surface.

[0089] In its motion, the bearing blade 3 separates the incoming water flow into the flow to the left water cushion and into the flow to the right water cushion, both being directed underneath the bottom surface of the boat's hull.

[0090] FIG. 2.1-2.2. explain the creation of a water cushion. The water flow incoming on the hull of the boat is divided by the bearing blade, is squeezed by the front part of the bottom surface, and rushes under the surfing surface into the left and the right water cushions. At the same time, the continued compression of the water flow is forcing the redistribution of its excess underneath the entire area of the water cushions, while the bearing blade prevents the [water] flow between water cushions.

[0091] At a sufficient speed of the incoming water flow, the compression of the [water] flow under the surfing surface leads to the formation of two laminar continuous streams—in the left and in the right water cushions, respectively, flowing underneath the surfing surface; with the further increase in speed, these [water] flows, without losing their laminarity and continuity, are breaking away from underneath of the stern and dissipate. Wherein the surfing surface “swells” on the water cushion, which leads to a sharp drop in the hydrodynamic resistance to the hull's movement, the boat accelerates quickly; the engines go into a low-loaded, high-rpm mode of operation; and the stern wave disappears.

[0092] The centre of the displacement of the bearing blade is located in its upper third, in the middle of the length of the hull. When the surfing surface “swells” on the water cushion, the centre of the displacement of the bearing blade becomes the rotation point of the hull by pitch, by 1-2 degrees. Wherein, the thrust arm “CTA” of the water cushion's thrust “CT” in relation to the centre of rotation constitutes approximately 25% of the length of the hull, wherein “swell” on the water cushion and rotation of the hull occur at moderate speeds of 14-15 knots, in a mild controlled mode, and further gliding on the water cushion is balanced in the longitudinal direction. At gliding on the water cushion, the bearing blade prevents slipping in the transverse direction, and the hull heads forward at high speed, wherein the thrust of the displacement of the front half of the bearing blade “BT” prevents an increase in the angle of rotation, and provides a stable angle of attack of the surfing surface. The hull is in a state of a stable, sustainable seaworthy surfing.

[0093] FIG. 3.1-3.5. illustrate the stabilisation of the hull. In the state with no motion (FIG. 3.1.), the longitudinal balancing is provided by the displacement force “BD” of the bearing blade (shown as distributed) and the displacement force of the submerged surfing surface “SD” (shown in the centre of its displacement). This ensures the required distance of elevation of the bottom surface “SE”, the required angles of descent of the bottom surface in the bow and stern parts in relation to the waterline, the required submerging of the surfing surface. The results of the sea trials of the claimed hull had demonstrated that the longitudinal balancing by the bearing blade is one of the most important conditions for the successful achievement of the seaworthy surfing mode.

[0094] In the mode of gliding on a water cushion (FIG. 3.2.), the longitudinal stability is provided by the combination of the thrust of the water cushion “CT” and the thrust of the front part of the blade “BT”, where the distance between them is approximately 50% of the length of the hull, a large stabilising moment is formed, that is, the claimed hull, unlike a planing hull, has two longitudinal widely separated support points, wherein the surfing surface is also incomparably larger in its size than the planing “sole” of the planing hull. With increasing speed, the effect of the longitudinal stabilisation increases, wherein at high speed the filling up of the water cushions increases, and the incoming waves have a lesser effect on the bearing blade.

[0095] In crossing a transverse wave (FIG. 3.3.), the wave is cut by the wave-piercing stem and passes along the hull of the boat, where the wave is squeezed by the bottom surface into the left and the right water cushions; thus, the impact of the wave on the front edge of the hull is absent; the wave creates an additional excess [water] flow in the water cushions, which does not affect the stability of the movement and the rolling/pitching of the hull.

[0096] In case of running without a wave (FIG. 3.4.), the water cushions are completely filled, the hull is constantly supported from below by the dynamic water flows “SR” and “SL”, and it cannot roll to the left or to the right without “squeezing” the water cushion, which is practically impossible. The bearing blade, with its two-sided thrust, “SB” being deep under water, prevents the roll of the hull.

[0097] At high speeds of a surfing glide, when the wave hits on the left (FIG. 3.5.), the left side of the hull rises, the flow of the left water cushion becomes thinner, and its excess in the left water cushion decreases and provides a smaller thrust “SL” to the left surfing surface; at the same time, the flow of the right water cushion, on the contrary, thickens and makes a greater thrust to the right half of the surfing surface “SR”; wherein the water flow being divided by the bearing blade cannot be moving from the right water cushion to the left one; thus the excess of water flow and of thrust in the right water cushion right up the hull; the bearing blade prevents the hull from slipping to the right, whereas such slipping is inevitable for the planing hulls in a similar situation. During practical tests, the claimed hull demonstrated that side waves cannot force a roll on a surfing stabilised hull with the bearing blade. When trying to create a roll, the wave on the left side encounters resistance including the sum of the hydrodynamic thrust of the entire right surfing surface on the water cushion, and hydrodynamic thrust of the entire deeply submerged bearing blade against the dynamic [water] flow; wherein the total mass of the dynamic water flow, which pushes against the right surfing surface and against the bearing blade, is huge as compared to the mass of the wave coming from the left side; in this case the hull does not roll.

[0098] The controllable hull of the displacement boat stabilised in the sea waves conditions and gliding on the water cushion opens up the broad prospects for construction of the high-speed seagoing boats. First of all, this is a fundamental improvement in a stability of the movement, and the absence of rolling/pitching and yawing in the open Sea, an increase in carrying freight capacity and fuel economy as compared with the planing hulls, at cruising speeds of 20 knots or more, since the energy of the propulsion units of the surfing hull is not wasted on a creation of the planing wave and on “pushing over” it. The speed of movement of the surfing hull is limited only by the friction of its bottom surface against the dynamic flow of the water cushion, and this friction can be further reduced by using, for example, the new generation of gliding coatings. Surfing hull possesses simplicity of structural elements.

[0099] The claimed stabilised hull can be made, for example, out of fiberglass, other composite materials, wood, metal, polyethylene, and their combinations, and/or other materials acceptable in boatbuilding.