EP0221078B1

EP0221078B1 - Water-crafts with trim stabilizers acting through a relatively long lever arm

Info

Publication number: EP0221078B1
Application number: EP85904137A
Authority: EP
Inventors: Corrado Scarfo; Guido Scarfo; Paolo Scarfo
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-08-23
Filing date: 1985-08-13
Publication date: 1990-04-25
Also published as: DE3577302D1; IT8448748A0; EP0221078A1; IT1179226B; WO1986001482A1

Abstract

Water-crafts having stabilizers acting through a relatively long lever, comprising aerial wings (4), applied to the purpose of stabilizing and lifting, to be applied on light and very light hulls, at the same time allowing short glides having as principal aim the stabilization, in the case of heavy crafts, comprising also aerial wings and/or nozzles (6) ejecting fluid under pressure, carried by the aforementioned wings (4) or other also underwater ones supports, the said stabilizers being, or not, automized ones. Such a stabilization system allows apply hydrodynamic wings (3-23) on both the sides of the very sharp bottom of a hull, that is remaining submerged, and allows apply, on the keel, hydrodynamic wings (3), if possible narrow, uninterrupted or splitted, ones, on suitable supports, if the hull rises on the water, reducing the width of the air-cushion in the Hovercrafts and in similar crafts to the purpose, respectively, of deeply ploughing the waters or skimming the water, always cutting the same. The course, the system allows also the stabilization of the conventional ships.

Description

It is well known that all crafts must aim at the reduction of rolling and pitching in the case of rough seas and at the same time at maintaining a high speed even in adverse meteo-marine conditions (GB-A-2007615, GB-A-1453663).
Objects of this invention are transversal and longitudinal trim stabilizers; as far as the longitudinal trim is concerned, if the ship allows it from a constructive point of view, the stabilizers act preferably through a sufficiently long lever-arm, in such a way as to drastically reduce needed and absorbed power.
According to the present invention as defined in claim 1 the stabilizing means, both in transversal and longitudinal stabilization, are carried out by aerial wings (4) equipped with controls and/or ejectors (5), however placed, acting by means of a relatively long lever-arm, if necessary interlocked with an automatized, preferably gyroscopic, system.
Of course, the concept of stabilization in the case of wing surface use doesn't exclude, nor could it reasonably exclude, especially in the case of smaller crafts, the concept of lift, on the contrary, it calls for it, with the following consequences.
The trim stabilizers, according to the present invention, are based on the idea of using or applying stabilizing means to aerial wings (4) and/ or to other means, including underwater ones, that are placed in a working position far from the ship's centre of gravity.
In this case, the greater fluidity of the air is especially exploited with a consequent reduction of friction and also of possible breakdowns, which occur, especially at high speeds, when the water becomes "resistant" to the presently used underwater stabilizing systems.
The invention will now be described in greater detail in the following specification, with reference to the schematic and exemplifying drawing attached, in which:

Figure 1 shows a water-craft equipped with aerial stabilizers according to the present invention, integrated by an underwater stabilizer;
Figure 2 shows a simplified water-craft equipped with aerial, transversal stabilizers and hydro- dynamic surfaces arranged keel-wise.
Figure 3 shows a simplified water-craft equipped with aerial stabilizers and with a particularly narrow air-cushion arranged keel-wise.

With reference to the aforementioned drawing and especially to figure 1, the craft (1) with its steep keel (2) shows small hydro-dynamic wings (3) placed on both sides of the pointed hull, small wings which have only a limited part in the lifting of the craft. Transversal stabilization is given by the aerial wings (4) equipped with balancing flaps (5) and preferably equipped with outflow nozzles (6), for fluids under pressure, also placed on the mast, whereas longitudinal stabilization is guaranteed by depth planes (7) placed on the wings and/or by a nozzle (8) placed at the end of the craft, and/or by the nozzle (9) placed on the part under the water-line, and which is four- shaped, i.e. two for transversal stabilization and two for longitudinal stabilization.
Similarly to what is shown in figure I, the water-craft 21, shown in figure 2, is equipped with aerial wings 24 with balancing flaps 25 and with small hydro-dynamic wings 23 placed along the keel, preferably keyed to a support beam 27. A different shape of the hydro-dynamic wings is possible, for example, one or more long and narrow wings, on condition that their position, with reference to the keel, be kept. In the aerial wings 24, the ejector nozzles and depth planes are not shown for reasons of simplicity.
The inventive idea of stabilization by means of aerial wings and/or nozzles for the outflow of fluids, carried by long lever-arms, finds special employment in water-crafts raised on an air-cushion and known throughout the world as "Hovercrafts".
The existence of aerial stabilizing means 34 (Figure 3), in fact, allows the air-cushion 38 to be kept very narrow and placed keel-wise, its main working purpose being that of keeping the water-craft raised above the surface of the water and the transversal stabilization being entrusted to the wings 24, either integrated or not with fluid outflow nozzles, for fluids under pressure (nozzles that are not shown in the picture), however arranged along a lever-arm, and the longitudinal stabilization to depth planes placed on the same wings and/or nozzles placed at the furthest end of the ship.
As it is possible to note from what has been previously stated, the basic idea of the invention is that of achieving aerial stabilization by means of a large lever-arm and increasing this stabilization by means of nozzles or ejectors which can also be placed on the water-craft's mast.
The idea of stabilization by means of a large lever-arm can also be utilized, of course, in the water by installing nozzles or supports characterized by a reduced resistance to movement, possibly, together with aerial stabilization, for special purposes too, such as a better distribution of anti-torsion movements within the craft.
Aerial stabilization in particular allows many advantages to be obtained: for example, the reduction of problems connected with shape stability in customary naval crafts, as it allows the use of a greater coefficient of keenness in the case of increased speed, with the possibility of reducing the dipped part of the craft to a sort of blade which may cut the water whatever the shape of the wave profile (also in the case it be abeam) without having to stand the stress which a craft having to rely solely on the stability of its shape cannot avoid. Also in the case of water-crafts of the Hovercraft type, as mentioned before, the reduction of the air-cushion width allows that the waves be crossed obliquely, besides, of course, the reduction of air outflow from the skirt or tunic.
As mentioned, aerial stabilization means allow that the water-craft - including "Surfs" - be given an aerial lift which may be utilized for different purposes, according to the size of the craft, keeping in mind that the weight of a water-craft increases according to the cube of its length. Allowing that the wings (4) may exceed relatively limited sizes, imposed for reasons of encumbrance, etc., the consequences are that, in the case of very small water-crafts, up to "Surfs", it is impossible to stress the excursions and the jumps out of the water, typical of offshores, and imitate the well-known "Flying Exocet", with short glides. In ships of a larger size, the wings (4) have prevalently stabilizing functions and represent a well outlined narrow support for balancing flaps (5) and depth planes (7) and/or fluid delivery nozzles (for air and/or water). It must furthermore be pointed out that the aforementioned stabilizing wings (4), in any case, if applied near to the prow, reduce the weight of the said prow, in the case of wavy sea, acting in the same way as the jib, flying jib and fore topmast stay-sails used to act.
Of course, as a result of the extension of the idea of aerial lift and stabilization, giving the small and very small crafts an asymmetrical profile with the higher portions characterized by a greater sheer, according to the Principle of Bernouilli, the craft itself can also contribute to the lift.
The water-crafts of the present invention have been described and shown only by way of example and not for any limitative purposes.

Claims

1. Water craft with trim stabilizers in which the stabilization is realised by aerial wings, characterized in that:

a) the stabilizers operate through a relatively long lever-arm and are formed by aerial wings (4, 24, 34) provided with control means and/or nozzles (6), and also provided with lever arms of under water-type, ejecting a fluid medium under pressure, said nozzles (6, 9) being carried by said wings and by said lever arms of under water type;

b) the stabilizers are, preferably, of the automated system type;
the width of the water-craft in the dipped part, or the width of the air-cushion in the Hovercraft-and derived types, thereby being reduced.

2. Water-crafts with trim stabilizers, in which the stabilizers are acting through a relatively long lever arm, according to Claim 1, in which are foreseen hydrodynamics wings (3-23) preferably narrow, uninterrupted or splitted ones and also on different planes, designed for remaining dipped and carried on both the sides of a very sharped bottom that are not lifting the water-craft on the water, but that are reducing the depth of the dipping of the same to the purpose of increasing the speed and reduce the resistance.

3. Water-crafts with trim stabilizers, in which the stabilizers are acting through a relatively long lever arm according to the previous Claim, in which the hydrodynamic lifting is entrusted to one or more hydrodynamically narrow, uninterrupted or splitted wings (3-23) placed along the keel on special supports (27) also laminar ones.

4. Water-crafts with trim stabilizers acting through a relatively long lever arm according to one or more of the previous claims, in which they are connected to a narrow air cushion, or similar means, placed along the keel.

5. Water-crafts with trim stabilizers according to the previous claims in which - in particular if of reduced size - the two outer wings (4, 24, 34) that are composing an aerial wing, are placed in elevation as a V with an angle at the - vertex inferior to 180 degree and with the vertex towards the lower part.

6. Water-crafts with trim stabilizers acting through a relatively long lever arm according to one or more of the previous claims in which the longitudinal stabilizing means is made by the same wings (4, 24, 34) used for the transversal one, but equipped furthermore of depth planes, the wings being placed at the maximum end of the ship.

7. Water-crafts with trim stabilizers acting through a relatively long lever arm, according to one or more of the previous claims, in which the outlet nozzles (6) of fluids under pressure are placed in discrete points of the wings and preferably to their ends and/or a point placed at the maximum distance, as a mast on the ship for the longitudinal and transversal stability, all it in addition to the balancing flaps or in their replacement and/or depth planes.

8. Water-crafts with trim stabilizers acting through a relatively long lever arm according to one or more of the previous claims in which the nozzles (6) of outflow of fluids under pressure have variable opening, are subjected to an automatized system and are placed for the transversal and longitudinal stabilization on one or more masts of the water craft for increasing to the maximum the lever arm and 9 for the transversal and longitudinal stabilization also eventually on underwater supports presenting a reduced resistance of the movement.

9. Water-crafts with trim stabilizers acting through a relatively long lever arm, according to one or more of the previous claims, in which the hull shows a biconvex asymmetrical profile, with the high part having a greater sheer according to the Bernoulli theorem.

10. Water-crafts of little and/or minimum size with trim stabilizers acting through a relatively long lever arm, according to one or more of the previous claims, in which the wings allow to the water-craft being raised above water and gliding for short aerial excursions.

11. Water-crafts of little and/or minimum sizes with trim stabilizers acting through a relatively long lever arm according to one or more of the previous claims in which half stabilizing wings are preferably placed in tandem i.e. towards prow and towards the stern, in one or more Surf tables, connected one to the other, any of them with a biconvex asymmetrial profile with the high part of greater sheer.