GB2110622A - Hybrid sail apparatus - Google Patents

Abstract

A hybrid sail apparatus composed of a rigid sail 4 having a flat, preferably aerofoil-shaped, cross- section, and a flexible sail 13 connected to the rear portion of the rigid sail. The hybrid sail apparatus has means for freely adjusting the angles of the rigid sail and the flexible sail in accordance with the direction and velocity of the wind. The apparatus may be provided with means including a sat retractable and extractable to and from the front or lateral side of the rigid sail so as to delay the separation of flow of air. Preferably, the rigid sail is constructed to be foldable at its heightwise mid portion to reduce the height of the rigid sail as desired thereby to avoid interference between the rigid sail and shore structures when the ship moves in a harbour, channel or the like. <IMAGE>

Description

SPECIFICATION Hybrid sail apparatus Background of the invention The present invention relates to a sail apparatus for running a ship, particularly a largesized ocean going ship, by making use of the force of wind. More particularly, the invention is concerned with a hybrid sail apparatus composed of a rigid sail having an aerofoil cross-section and a flexible sail provided atthe rear side of the rigid sail.

Current rise of crude oil price is promoting the discussion and study on utilization of wind force as an auxiliary power for running ships, particularly large-size ocean going vessels.

Examples of known means for utilizing the wind force are a sail apparatus having a rigid sail developed on a mast and a so-called composite or hybrid sail apparatus composed of a rigidi sail serving also as a mast and a flexible sail adapted to be developed in close proximity of the rigid sail. These sail apparatus are required to permit an easy development and setting of the sails as compared with conventional sail apparatus.

Namely, the modern sail apparatus under consideration is required to have an automatic sail operation system to reduce the number of crew members necessary for the sail operation.

At the same time, the rigid sail is intended to function also as an aerofoil so as to make an efficient use of the dynamic lift produced by the rigid sail in running the ship.

In the hybrid sail apparatus, in order to improve the effect of the rigid sail, the rigid sail is shaped to exhibit an aerofoil cross-section and is made rigid enough to prevent any deformation by the wind force, while the flexible sail is adapted to be developed in close contact with the rear end of the rigid sail.

In the known composite sail apparatus, however, it is quite difficult to freely adjust the angle formed between the rigid sail and the flexible sail and, hence, to make the most of the wind force.

In the actual use of the composite sail apparatus, it is necessary to operate the flexible sail in accordance with the condition of wind such that the flexible sail is opened fully or partly or, when not used, fully set to minimize the aerodynamic resistance.

In the known composite sail apparatus, however, many hands are required for setting the flexible sail or, alternatively, the flexible sail cannot be fully set resulting in a considerably large aerodynamic resistance.

As stated before, in the hybrid sail apparatus, the flexible sail is adapted to be developed in close contact with the rear end of the rigid sail having an aerofoil-shaped cross-section. In this hybrid sail apparatus, separation of air stream often takes place on the flexible sail. Once the separation of air stream takes place, the performance of the sail apparatus is deteriorated seriously.

The rigid sail of the hybrid sail apparatus for large-size ships is an extremely tall structure having a height well reaching 30 to 80 m. With such tall structure, the ship cannot run along the channels or rivers because of possibility of interference with the shore structures.

For these reasons, the area of movement of large-size ships having known composite sail apparatus has been limited undesirably.

Summary of the invention Accordingly, the invention aims as its major object to provide a hybrid sail apparatus capable of overcoming the above-described problems of the prior art.

Namely, it is a first object of the invention to provide a hybrid sail apparatus composed of a rigid sail and a flexible sail, improved to permit an easy adjustment of the positional relationship between the rigid sail and flexible sail in accordance with the condition of the wind.

It is a second object of the invention to provide a hybrid sail apparatus having a slat for delaying the separation of air on the upper side (vacuum side) of the hybrid sail apparatus thereby to increase the maximum aerodynamic lift coefficient, and means for facilitating the operation of the slat while making efficient use of the slat.

It is a third object of the invention to provide a hybrid sail apparatus having means for developing and setting the flexible sail to the desired state for making full use, partial use and no use of the wind force.

It is a fourth object of the invention to provide a hybrid sail apparatus which does not limit the movement of the ship, in view of the fact that the rigid sail hitherto used for large-sized ships, having large height well reaching 30 to 80 m, often limits the movement of the ship along the port facility or channel.

According to one aspect of the invention, there is provided a hybrid sail apparatus having a rigid sail having an aerofoil-shaped cross-section and a flexible sail connected to the rigid sail, characterized by comprising means for adjusting the angle formed between the rigid sail and the flexible sail.

According to another aspect of the invention, there is provided a hybrid sail apparatus comprising a stretchable and settable fore sail (slat) provided on each side or on the front edge of the rigid sail.

According to still another aspect of the invention, there is provided a hybrid sail apparatus, wherein the rigid sail is composed of an upper half part and a lower half part and is foldabie at the joint between two half parts.

The present application includes a plurality of embodiments of the invention as summarized hereinbelow.

According to a first embodiment, there is provided a hybrid sail apparatus having a rigid sail which can hardly be deformed by the wind force and a flexible sail which is deformable to some extent by the force of the wind.

According to a second embodiment, there is provided a hybrid sail apparatus in which the angle formed between the rigid sail and the flexible sail is adjustable.

According to a third embodiment, there is provided a hybrid sail apparatus comprising a slat attached to the upper side (vacuum side) of the rigid sail, the slat being adapted to delay the separation of air on the upper side (vacuum side) of the sail apparatus thereby to increase the maximum lift coefficient.

According to a fourth embodiment, there is provided a hybrid sail apparatus having such a slat disposed at the front side of the rigid sail which is adapted to be turned toward starboard and port sides to open and close relative to the rigid sail, and also adapted to be double folded at substantially the mid point of its length in a manner such that in its double-folded position the slat can form part of the rigid sail.

According to a fifth embodiment, there is provided a hybrid sail apparatus, comprising a driving mechanism provided on the front portion of the rigid sail, the driving mechanism being adapted to support the slat and to drive the same between a retracted position and an extended position.

According to a sixth embodiment, there is provided a hybrid sail apparatus comprising a horizontal winding shaft disposed horizontally at the lower end of the rigid sail so as to wind up the flexible sail from the lower end of the same.

According to a seventh embodiment, there is provided a hybrid sail apparatus comprising a pair of pinch rollers disposed at the lower end portion of the flexible sail, the pinch rollers being adapted to feed the flexible sail by pinching the lower end of the same thereby to set the flexible sail.

According to an eighth embodiment, there is provided a hybrid sail apparatus wherein means are provided to rotate the rigid sail thereby to wind the flexible sail around the rigid sail.

According to a ninth embodiment, there is provided a hybrid sail apparatus comprising a plurality of winding shafts arranged at a predetermined distance from the trailing edge of the rigid sail, the width of the flexible sail being changeable by the winding shaft.

According to a tenth embodiment, there is provided a hybrid sail apparatus comprising a winding shaft mounted in the hollow of the rigid sail, the width of the soft sail being changeable by this winding shaft.

According to an eleventh embodiment, there is provided a hybrid sail apparatus comprising a winding shaft supported at its one end by an upper portion of the rigid sail while the lower portion of the shaft being guided to move along an arcuate boom so that the flexible sail is wound up in a triangular form starting from its end remote from the rigid sail.

According to a twelfth embodiment, the rigid sail is divided at its mid portion along a chord into two halves, the two halves being pivotally connected to each other by a hinge, so that the rigid sail has an upper part and a lower part which are foldably jointed to each other at the juncture surfaces thereof.

According to a thirteenth embodiment, there is provided a hybrid sail apparatus wherein the rigid sail is provided in a central portion thereof with a tubular body to which a number of ribs are secured and metallic sheets are applied surrounding the ribs to structure the rigid sail of an aerofoil section.

Brief description of the drawings Fig. 1 is a schematic perspective view of a hybrid sail apparatus embodying the present invention; Figs. 2A and 2B show a hybrid sail apparatus in accordance with an embodiment of the invention having two slats arranged on both sides of the rigid sail, one of the slats having been moved away from the side surface of the rigid sail; Fig. 3 is a perspective view of a hybrid sail apparatus embodying the present invention; Figs. 4, 5 and 6 are illustrations of a hybrid sail apparatus of the invention composed of a rigid sail having an aerofoii-shaped cross-section and a slat disposed at the front side of the rigid sail and foldable in the longitudinal direction thereof at its mid portion, showing how the slat is operated; Figs. 7 and 8 are perspective views of a constructon for opening and closing a slat provided on the edge of the rigid sail;; Fig. 9 is a sectional view of a hybrid sail apparatus having a slat retractable and extractable into and out of the rigid sail; Fig. 10 is a graph showing the relationship between the aerodynamic lift coefficient and the drag coefficient in a hybrid sail apparatus having only a rigid sail and a flexible sail and in a hybrid sail apparatus having a slat in addition to the rigid sail and a flexible sail; Fig. 11 is a perspective view of a sail apparatus having a mechanism for adjusting the angle between the rigid sail and the flexible sail and a winding shaft provided on the rear end of the rigid sail and adapted to wind up the flexible sail; Fig. 12 is a perspective view of a hybrid sail apparatus having a winding shaftforwinding up the flexible sail, the shaft being mounted in the hollow of the rigid sail; ; Fig. 1 3 is a perspective view of a hybrid sail apparatus having a winding shaft supported at its one end by an upper portion of the rigid sail while the other end is supported for movement along an arcuate boom; Fig. 14 is a perspective view of an essential part of a hybrid sail apparatus having a pair of pinch rollers adapted to take up the flexible sail from the lower end of the flexible sail by pinching the lower end thereof; Fig. 1 5 is a perspective view of an essential part of a driving mechanism for driving the pinch rollers; Fig. 1 6 is a perspective view of an essential part of a hybrid sail apparatus having a flexible sail winding shaft extended along the boom and having a mechanism for adjusting the angle between the rigid sail and the flexible sail;; Fig. 1 7 is a side elevational view of an essential part of the flexible sail winding device shown in Fig. 16; Figs. 18 and 19 are a side elevational view and a plan view of an essential part of a device having a wire connected to the mid portion of the boom and adapted to swing the boom; Figs. 20 and 21 are perspective views of essential parts of the mechanism for adjusting the angle formed between the flexible sail and a rigid sail; Fig. 22 is a perspective view of a mechanism for adjusting the angles of the rigid sail and the flexible sail relatively to each other; Fig. 23 is a perspective view of a hybrid sail apparatus in which the rigid sail is divided at its mid portion into two parts foldable with respect to each other;; Fig. 24 shows the state of operation of the sail apparatus shown in Fig. 23; Fig. 25 is a side elevational view of an essential part of a composite sail apparatus shown in Fig.

23; Fig. 26 is a front elevational view of a foldable rigid sail; Fig. 27 is a side elevational view of the foldable rigid sail; Figs. 28 to 31 are detailed sectional views of the rigid sail; Fig. 32 is a sectional view showing the detail of mounting of the outer panels constituting the rigid sail; Figs. 33 and 34 are a side elevational view and a front elevational view of the folding connection between two parts of the rigid sail, respectively; Fig. 35 is a sectional side elevational view showing the internal structure of the foldable connection in the rigid sail as shown in Fig. 33; and Fig. 36 is a sectional view taken along the line X-X in Fig. 35.

Detailed description of the preferred embodiments Preferred embodiments of the invention will be described hereinunder with reference to the accompanying drawings.

Basic construction of hybrid sail apparatus The hybrid sail apparatus of the invention has a combination of a rigid sail and a flexible sail. The rigid sail is a light-weight one having a shape resembling that of a wing of airplane, preferably of an aerofoil-shaped cross-section, while the flexible sail is a foldable one continuously connected to the rear end of the rigid sail. The rigid sail and the flexible sail are arranged in such a manner that the relative angle therebetween is adjustable.

More preferably, the hybrid sail apparatus of the invention has a slat provided on the front portion of the rigid sail for free opening and closing, the slat having a function to prevent separation of air stream flowing along the surface of the sails, particularly the flexible sail.

Fig. 1 is a perspective view of a first embodiment of the invention, showing the basic construction of the said apparatus in accordance with the invention, while Figs. 2A and 2B are perspective views showing the state in which one of the slats is opened.

Referring to these Figures, a rigid sail (referred to also as "mast sleeve") 4 having an aerofoilshaped cross-section is rotatably supported through a bearing 3 around a main post (referred to also as "mast") 2 standing upright from a deck 1. A ring-shaped gear 5 concentric with the mast 2 is fixed to the lower end of the rigid sail 4. A furling gear 6 meshing with the ring gear 5 drives the latter thereby to rotate the rigid sail 4.

A foldable and flexible sail 13 having a substantially triangular shape and provided with edge reinforcing canvass 13A is secured to the rear end of the rigid sail 4 rotatably attached to the mast 2.

A hariyard 14 has one end fixed to the upper end of the flexible sail 13 and extends through the hollow rigid sail 4 to make the other end thereof wound up by the winding up device (not shown).

A rope 1 5 fixed to the pointed lower end of the flexible sail 1 3 has one end taken up by a winch 16 which is secured to the end of the boom 8.

Normally, the rope 1 5 is fully taken up to permit the flexible sail 13 to develop over the entire length of the boom 8.

To explain in more detail the construction of the rigid sail 4, the rigid sail 4 is provided on its both sides with slats 22A and 228 constituting a pair, as will be seen from Figs. 2A and 2B. The slats 22A and 22B have aerofoil-shaped crosssection and am normally held in close contact with the side surfaces of the rigid sail 4 so as to constitute parts of the side surfaces of the rigid sail 4. Then, the slat 22A or 22B on the vacuum side of the rigid sail 4 with respect to the direction of wind Wis extended, i.e. moved towards the front side of the rigid sail 4 as shown in Fig. 2B, in accordance with change in the direction and velocity of the wind, thereby to prevent separation of the air stream on the rigid sail 4 and the flexible sail 13.

A later-mentioned driving mechanism can be used for driving the slats 22A and 22B.

In the case where the wind is strong, it is necessary to fold or shrink the flexible sail 1 3. To this end, fore sails or slats 22A and 22B are brought into close contact with both side surfaces of the rigid sail 4 and, thereafter, the furling gear 6 is rotated to drive the ring gear 5 meshing therewith. As a result, the rigid sail 4 is rotated so that the flexible sail 1 3 is wound around the rigid sail 4.

Needless to say, the winch 16 is reversed to pay off the rope 15 in synchronization with the winding up of the flexible sail 13.

In this first embodiment of the invention, the boom 8 is rotatably supported on the mast 2 fixed to the deck 1, and the rigid sail 4 is adapted to rotate in the direction of the arrow A around the axis of the mast 2. It is, therefore, possible to adjust the angle of the flexible sail 1 3 relative to the rigid sail 4 as desired. It is thus possible to obtain the optimum relative angle between the rigid sail 4 and the flexible sail 13 in accordance with the direction and velocity of the wind as well as the attack of the sail apparatus.

Furthermore, in this first embodiment of the invention, the storage of the sails in the case of strong wind is facilitated because the flexible sail 13 can be wound round the rigid sail 4 with the slats 22A and 22B held in close contact with the surfaces of the rigid sail 4. In addition, since no shaft is used for winding up the flexible sail 13, it is possible to reduce the thickness of the rigid sail remarkably as compared with the conventional rigid sail.

The reduced thickness of the rigid sail not only minimizes the resistance during running against wind but also permits a smooth connection between the rigid sail and the flexible sail thereby to afford a sufficient aerofoil-shaped crosssection. In addition, it is possible to easily wind up the flexible sail even when the latter is provided with a camber. Thus, the hybrid sail apparatus of this embodiment has a superior performance to well satisfy the requirements stated before.

Construction of slat In the composite sail apparatus, it is necessary to mount a slat on the front upper side of the rigid sail in order to delay the separation of the air stream thereby to increase the maximum lift coefficient. Required also is a mechanism for retracting and storing the slat at the front side of the rigid sail, when the slat is not used as in the case of strong wind.

Figs. 3 to 8 show a second embodiment of the invention. Referring to Fig. 3, a supporting member 20 is provided to project from the front side of the rigid sail 4 having an aerofoil-shaped cross-section. A slat 22 is supported through a slat driving device 21 fixed to the end of the supporting member. A cylinder device, torque hinge or a wire driving device can be used as this slat driving device.

As will be seen from Figs. 7 and 8, the rigid sail 4 is connected to the slat 22 through an arm 21A which is foldable at a joint to which connected is a rope 21B. The rope 21B is pulled and released by the cylinder device 21 C to swing the arm 2 1A thereby to open and close the slats 22A and 228.

Namely, the slat 22 provided at the front side of the rigid sail 4 is divided at its mid portion along the length thereof into two slats 22A and 22B, and the slat 22 is adapted to be pivoted at its mid portion to open and close by the action of the supporting members 20 and the driving devices 21 or by the arms 2 1A and the ropes 218 connected to the joints of the arms 2 1A by means of the cylinder device 21 C. It is, therefore, possible to swing the slats 22A and 22B to the left and right with respect to the rigid sail 4 and to fold the slat 22 as a whole at its mid portion to swing the slats 22A and 228 towards and away from each other, by activating the driving devices 21 or the cylinder devices 21 C.

Figs. 7 and 8 show the arrangement on the starboard side of the ship but the same arrangement is made on the port side of the same. With these arrangements, it is possible to open and close the slat or to develop the same at the port or starboard side as required.

An explanation will be made hereinunder as to the operation of the rigid sail 4 provided with the slats 22A and 228.

Fig. 4 is a plan view of the rigid sail in which the slat on the port side is developed. In this state, the wind Wimpinges from the port side as indicated by an arrow and is received by the slats 22A and 22B so as to be deflected towards the starboard side as indicated by an arrow W1.

Fig. 5 is a plan view of the rigid sail in which the slat on the starboard side is developed. In this case, the wind Wcoming from the direction W2 is trapped and is deflected to the port side as indicated by an arrow W3.

Fig. 6 shows the rigid sail in the state in which the slat 22 is not used. In this case, the slats 22A and 22B are folded towards each other at the mid portion of the slat 22 to locate their free ends in contact with the surfaces of the rigid sail 4 or to keep the same in the close proximity of the surfaces of the rigid sail 4. In this state, the slats 22A and 22B are substantially united with the rigid sail 4 so that the slats 22A and 22B serve as a part of the rigid sail 4. Namely, the chord length of the rigid sail 4 is materially increased by the length of supporting member 20.

As will be seen from Figs. 3 to 8, the slats 22A and 22B of the hybrid sail apparatus of the second embodiment do not necessitate any space for accommodating the slats 22A and 22B on the surfaces of rigid sail 4. In addition, the mechanism for accommodating the slats 22A and 228 can be simplified remarkably, because the slats 22A and 22B are simply supported by the driving devices 21 which in turn are supported by supporting members projected from the front end of the rigid sail 4.

Furthermore, when the slats 22A and 228 are moved to be united with the rigid sail 4, the slats 22A and 22B and the rigid sail 4 in combination form a rigid sail of a larger size thereby to ensure a higher performance over that performed by the sail apparatus of the first embodiment.

In place of the means for driving the slats 22A and 22B to the desired portion of the rigid sail 4 explained hereinbefore in connection with the second embodiment, it is possible to use means which will be explained hereinunder as the third embodiment.

Fig. 9 is a sectional view showing an essential part of the third embodiment. In the third embodiment of the invention, supporting members 25 are secured to the inner surfaces of both sides of the front edge of the rigid sail 4 so as to support the slats 22A and 228. These supporting members 25 are adapted to be moved back and forth by means of a jack screw 26 so that the slats 22A and 22B are moved with respect to the rigid sail 4 together with the supporting members 25 which are guided by guide rolls 25A. It is thus possible to set the slats at any desired portion on the rigid sail 4.

Namely, referring to Fig. 9, when the wind blows in the direction W4, the jack screw 26 is operated to set the slat 22A at a position projecting forwardly from the front edge of the rigid sail 4, whereas the other slat 22B is held in close contact with the rigid sail 4. Thus, it is possible to use either one of two slats 22A and 22B in accordance with the direction of the wind.

Needless to say, the rigid sail 4 is supported by the mast 2 through the bearing 3 as shown in Fig.

1.

Fig. 10 is a polar diagram showing the lift coefficient CL in relation to drag coefficient CD as obtained through an experiment conducted with a hybrid sail apparatus of the invention having the slats 22A and 22B in addition to the rigid sail and the flexible sail, in comparison with that obtained with a conventional hybrid sail apparatus consisting of the rigid sail and the flexible sail but devoid of the slats 22A and 228. From this Figure, it will be seen that the hybrid sail apparatus of the invention having the slats 22A and 228 provides greater lift coefficient CL (see curve X) than that (see curve )/) offered by the conventional slat apparatus. The greater value of the lift coefficient obviously ensures a higher performance of the sail apparatus.

According to the third embodiment, therefore, it is possible to attain high performance of the hybrid sail apparatus by the action of the slats 22A and 22B, by suitably operating these slats 22A and 22B in connection with the rigid sail 4.

Particularly, it is to be noted that, in the third embodiment of the invention, it is possible to take the optimum shape and position of the slat in accordance with the flow of air guided by the hybrid sail apparatus. In addition, the third embodiment of the invention offers a practical advantage in that, when there is no need for the slats 22A and 228, the slats can be kept in close contact with the surfaces of the rigid sail.

Shape of rigid sail The rigid sail 4 optimumly has an aerofoilshaped cross-section as shown in Figs. 2 and 3, but the invention does not exclude the adoption of modified cross-sectional shape such as oval shape, elliptic shape and so forth. It is, however, preferred that the rigid sail as a whole has a generally flat shape so that the rigid sail can produce an aerodynamic lift by itself.

Material of rigid sail The rigid sail 4 may be made from a steel plate, stainless steel plate or aluminum alloy plate or a composite material consisting of these materials and a plastic or F.R.P.

Shape of flexible sail The flexible sail 1 3 can have a triangular shape as shown in Figs. 1 and 3 or a modification of triangle, e.g. a form resembling a quarter of an ellipse formed by expanding the oblique side in an arcuate form, as well as a rectangular form and its modification. Preferably, the flexible sail 1 3 is made from a fabric of a high-tension fibers such as polyester long fibers, having an impermeable and weather resisting coating layer.

Mechanism for developing and folding flexible sail The state of opening of the flexible sail is controlled in such a manner that it is fully developed to make full use of the wind force when the wind is moderate, whereas, when the wind is too strong, the flexible sail is partially developed to make a partial use of the wind force.

When the flexible sail is not utilized, it is necessary to minimize the aerodynamic resistance. It is, therefore, necessary to employ a suitable means for developing and housing the flexible sail as desired.

As explained before in connection with first embodiment (see Figs. 1 and 2), it is possible to house the flexible sail 13 by bringing the slats 22A and 228 into close contact with the surfaces of the rigid sail 4 and then rotating the rigid sail 4 to take up the flexible sail 13 around the surfaces of the rigid sail 4.

This method for housing the flexible sail 13, however, imposes a problem that the resistance against the flow of air is increased because the surfaces of the rigid sail are unsmoothed by the flexible sail 13 wound round the rigid sail. It is, therefore, advisable not to cover the surfaces of the rigid sail with such a material as the flexible sail.

The invention proposes as its fourth embodiment a hybrid sail apparatus which is improved to facilitate the development and housing of the flexible sail.

Referring to Fig. 11 which is a perspective view of a flexible sail winding device, the rigid sail has an aerofoil-shaped cross-section and is supported at its lower portion on a sail support base 27 (or a mast). The rigid sail is rotatable by a rotary bearing 23 having a ring gear and a driving motor 28 having a pinion meshing with the ring gear.

A flexible sail winding shaft 30 is extended in the axial direction of the rigid sail 4 along the rear end edge of the latter with a space left therebetween. The shaft 30 is rotatably supported at its upper end by the upper end of the rigid sail 4, while the lower end thereof is connected to a motor 31.

Pulleys 32 and 33 guide a rope 34 fixed to the lower end of the flexible sail 1 3 when the rope 34 is wound up by a winch 35. A boom driving mechanism 36 is connected between the boom 8 and the sail supporting base 27 at the rear side of which the boom 8 extends. The boom driving mechanism 36 permits the camber of the flexible sail 13 with respect to the rigid sail 4.

When the rigid sail 13 is wound up by the flexible sail winding device of this embodiment, the flexible sail winding shaft 30 is rotated by the power derived from the motor 31. In this embodiment of the invention, therefore, it is possible to easily develop and fold the flexible sail 13 and, hence, to set the flexible sail 13 at any desired developing area.

Referring now to Fig. 12 showing a fifth embodiment of the invention, a flexible sail winding shaft 30 is accommodated by the hollow in the rigid sail 4. Although not illustrated in detail, a slit of a comparatively small width is formed in the rear part of the rigid sail 4 so that the flexible sail 1 3 can be extracted and retracted through this slit. To this end, the flexible sail winding shaft 30, adapted to be driven by a motor 31, is disposed in the vicinity of the slit.

In the embodiment shown in Fig. 12, the flexible sail winding shaft 30 is accommodated by the hollow in the rigid sail 4, and the flexible sail 13 is extracted and retracted through the narrow slit formed in the rigid sail. It is, therefore, possible to minimize the resistance produced by the flexible sail 13 in the housed state. When the flexible sail 13 is fully wound round the flexible sail winding shaft 30, the ship can run by the wind force acting only on the rigid sail 4, whereas, when the flexible sail 1 3 is partially developed, the rigid sail 4 and the developed portion of the flexible sail 13 receives the wind force.

It is preferred that the diameter of the flexible sail winding shaft is decreased along the length towards the upper end. The angle of taper of this winding shaft 30 is preferably selected such that the upper portion of the flexible sail remains to the last of the winding operation when the flexible sail 13 is taken up into the rigid sail 4.

By mounting the flexible sail winding shaft 30 at a distance from the rear end of the rigid sail as in the embodiment shown in Fig. 11, it is possible to wind up the flexible sail 1 3 easily with a simple winding device.

In the embodiment shown in Fig. 12, the flexible winding shaft 30 is accommodated by the hollow in the rigid sail 4 to maintain the flexible sail 1 3 materially integral with the rigid sail 4, so that the flow resistance can be minimized advantageously.

In the embodiment shown in Fig. 11, it is possible to easily take up the flexible sail 13 because the flexible sail winding shaft 30 is extended in the axial direction of the rigid sail 4 at a suitable distance D from the latter.

When the sail apparatus of the invention is developed to provide an equal area to the conventional sail apparatus, the flexible sail can have a comparatively small length in the direction of flow of the wind, so that it is possible to make more efficent use of the wind than the conventional sail apparatus.

In the embodiment shown in Fig. 12 in which the flexible sail winding shaft 30 is mounted in the hollow in the rigid sail 4, the undesirable increase of the resistance can be avoided because the shaft 30 is not exposed to the outside nor the flexible sail 13 is wound round the surfaces of the rigid sail.

Fig. 13 shows a sixth embodiment of the invention.

In this embodiment, the rigid sail 4 having an aerofoil-shaped cross-section is rotatably supported by the sail supporting base 27. An arcuate boom 8A is extended at a lateral side of the rigid sail 4 and is centered at a bearing (universal joint) provided on the upper end of the rigid sail 4. A boom driving mechanism 36 such as a hydraulic cylinder is connected between the boom 8A and the supporting base 27. The boom 8A is swingable in the horizontal direction around the sail supporting base 27.

The flexible sail winding shaft 30A has a conical shape in conformity with the shape of the flexible sail 13. A driving mechanism 39 for driving the shaft 30A is provided at the lower end of the shaft 30A. The driving mechanism 39 has a function to drive the flexible sail winding shaft 30A, as well as to shift the shaft 30A in the longitudinal direction of the boom 8A.

Although in the illustrated embodiment the shaft 30A for winding up the flexible sail 13 is exposed from the rear side of the rigid sail 4, the shaft 30A may be completely housed by the rear part of the hollow in the rigid sail 4.

In the sixth embodiment shown in Fig. 13, the flexible sail winding shaft 30A is supported at its upper end by the upper end of the rigid sail 4 while the lower end of the same is movable along the arcuate boom BA, so that the flexible sail 13 is wound up from its end of outer edge or rewound in accordance with the rotation and movement of the shaft 30A. It is, therefore, possible to wind up the flexible sail 13 in conformity with the shape of the flexible sail 1 3 and, hence, to develop and house the flexible sail 13 without permitting any shiver of the same.

Furthermore, since the flexible sail 13 is supported at its edges by the rigid sail 4 and the flexible sail winding shaft 30A, it is possible to develop the flexible sail 13 to provide exactly the required developing area.

In the first, fourth, fifth and sixth embodiment of the invention shown in Figs. 1, 11, 12 and 13, the flexible sail 13 is taken up from the side edge thereof. This, however, is not exclusive and the flexible sail 13 may be taken up from the lower end thereof.

Figs. 14 and 15 are perspective views of a seventh embodiment of the invention.

Referring to Fig. 14, the seventh embodiment is characterized in that a pair of take-up rollers 40 are provided on the upper end of the boom 8. The flexible sail 13 is fed and taken up by these rollers into the boom 8B.

Fig. 1 5 shows the detail of the mechanism for driving the take-up rollers 40. The right one of two take-up rollers 40 is held stationarily and is adapted to be driven by a take-up roller driving motor 43 through a gear 41, idler gear 42 and a gear 50, while the other roller is pressed against the first-mentioned roller through a guide 44 by a spring 45 and is adapted to be driven by the driving motor 43 through a sprocket 46 provided on this roller 40, chain 47 and a sprocket wheel 48.

A ratchet 52 is provided at one side of the gear 50 and is associated with a ratched releasing device 53.

In winding up the flexible sail 13 with this flexible sail winding up device, the flexible sail 13 is pinched and pulled downwardly by two rollers 40 as shown in Fig. 1 5.

An explanation will be made hereinunder as to how the device of the seventh embodiment shown in Fig. 14 is operated. In winding up the flexible sail 13, the flexible sail 13 is taken up downwardly by the take-up rollers 40, while paying off the wire 55 from the sail developing winch 54.

In this seventh embodiment, it is possible to exactly and easily house the flexible sail 1 3 from the end thereof, because the flexible sail 1 3 is pinched and taken up by two take-up rollers 40.

Although in the described embodiment the take-up rollers 40 are extended in the longitudinal direction of the boom 88, this is not exclusive and the rollers 40 may be extended, for example, in the axial direction of the rigid sail 4. In the latter case, it is preferred to mount two rollers in the hollow of the rigid sail 4 so as to extend the axial direction of the latter, so as to take up the rigid sail 4.

Referring now to Figs. 16 and 1 7 showing an eighth embodiment of the invention, a boom is extended at a lateral side of the sail supporting base 2. A driving device 56 is provided on one end of the flexible sail winding up shaft 51 extended in parallel with the boom 8 so as to drive the shaft 51 at a predetermined speed. A camber adjusting device 57 provided on the boom 8 is adapted to move in the direction of the arrow Eso as to vary the angle formed between the flexible sail 13 and the rigid sail 4, i.e. the camber angle.

Fig. 17 shows a driving device for driving a flexible sail winding shaft 51. The driving device includes a bearing 56a, clutch 56b and a winch 56c. The winch 56c winds up or unwinds a hariyard 14 thereby to raise the lower and flexible sail 13.

In the seventh and eighth embodiments described hereinbefore, the flexible sail 13 is taken-up and housed in the downward direction so that the resistance against air is reduced when the flexible sail is fully taken up. For the same reason, the repair and replacement of the flexible sail are facilitated. Also, it becomes possible to fold the rigid sail 4 as in the case of an embodiment which will be described later.

Adjustment of angles of rigid sail and flexible sail In order to make an efficient use of the wind force, it is necessary to adjust the angles of the rigid sail and the flexible sail in accordance with the state of the wind.

Figs. 1 8 and 1 9 show a mechanism for supporting and driving the boom 8. The boom 8 is secured to the mast 2 through a goose neck 7 for a swinging substantially over 1800 within a horizontal plane. A wire 60 wound round the drum 62A of a winch 62 is connected at its one end to an intermediate portion of the boom 8.

Another end of the wire 60 wound round another drum 628 is connected to the same portion of the boom 8. It is possible to swing the boom 8 around the mast 2 to the desired position by taking up or paying off the wire 60 to and from the drums 62A and 628 through deck shieves 59 provided on the brackets 58 on the deck.

In the eighth embodiment of the invention shown in Fig.16, the camber adjusting device 57 is provided on the boom 8, and the angle formed between the flexible sail 1 3 and the rigid sail 4, i.e. the camber, can be adjusted by moving the adjusting device 57 in the direction of the arrow E.

Referring now to Fig. 20 showing a practical example of the camber adjusting device, a connecting rod 70 is connected at its one end to the driving end (a kind of crosshead) 69 of the camber adjusting device 57, while the other end of the same is rotatably carried by a shaft 72 in a notch provided in the lower side portion of the rigid sail 4.

Fig. 21 shows the operation of the hybrid sail apparatus of the invention shown in Fig. 20. The arrangement is such that the driving end 69 is moved in the direction of the arrow K as the camber adjusting device 57 provided on the end of the boom 8B is driven. As the driving end 69 is moved in this way, the rigid sail 4 is rotated in the direction of the arrow L by the connecting rod 70 connected to the driving end 69.

The camber driving device 75 shown in Figs.

20 and 21 can employ a hydraulic cylinder, hydraulic motor or an electric motor with or without the assist by a gear mechanism. The adjustment of the angle of the boom 8 can be made by taking up or paying off the wires 10 connected to the end of the boom 8 (see Fig. 1) or the wires 60 connected to an intermediate portion of the boom 8. As an alternative, the boom 8 may be rotated directly by a hydraulic device shown in Figs. 3,11,12,13 and 14.

In the eighth embodiment of the invention shown in Fig. 16, the angle of the rigid sail 4 can be set freely regardless of the swinging of the flexible sail 13, so that the angle formed between the rigid sail 4 and the flexible sail 13 can be set as desired in accordance with the velocity and direction of the wind. This arrangement provides a greater lift/drag ratio as compared with the case where the angle of the flexible sail solely is adjustable, as well as a greater maximum lift coefficient than that obtained when the rigid sail is used solely. In consequence, the aerodynamic characteristics of the sail apparatus can be improved to remarkably increase the efficiency of use of the sail apparatus.

As stated before, in the hybrid sail apparatus, it is important to adjust as desired the angle formed between the boom 88 and the rigid sail 4. Fig. 22 shows a ninth embodiment of the invention having a specific means for rotating the boom 8B with respect to the rigid sail 4. More specifically, Fig. 22 is a perspective view of the ninth embodiment which is identical to preceding embodiments in that the rigid sail 4 is protruded from the sail supporting base 2 and is adapted to be rotated thereon. In this ninth embodiment, however, the boom 8 is extended horizontally at the lower portion of the rigid sail 4 and is rotatably carried by a shaft 66. The boom 8 is hollow and accommodates a flexible sail winding shaft 65 so as to wind the flexible sail 13 from the lower end of the latter.

An adjusting device 61 provided on the end of the boom 8 is adapted for permitting as adjustment of the angle between the rigid sail 14 and the flexible sail 13.

In the ninth embodiment of the invention having the described embodiment, by driving a rotating device 67, the rigid sail 4 is rotated in the direction of the arrow H while the boom 8 can be swung by the adjusting device 61 as indicated by the arrow.

Construction of the rigid sail As stated before, the rigid sail for use in largesize ships is an extremely large-size structure having a breadth as large as about 5 m and a large height well reaching 30 to 80 m.

Therefore, difficulty is often encountered when the ships gets into a port or moved through a channel or river with the rigid sail standing upright, due to interference with shore structures in the harbour or along the river.

In order to obviate this problem, the present invention proposes also a hybrid sail apparatus in which the rigid sail is divided substantially at its mid portion into two halves along a plane including the chordal line, the two halves being foldably connected to each other by a hinge.

Figs. 23, 24 and 25 are perspective views of a hybrid sail apparatus in accordance with a tenth embodiment of the invention. In this embodiment, the rigid sail 4 is divided into an upper structure, i.e. an upper rigid sail 48 provided with an extension 80 and a lower structure, i.e. lower rigid sail 4A provided at its central portion with a recess 81 for receiving the extension 80.

The extension 80 has a rectangular form when viewed from the front side but has a triangular form tapered toward the pointed end when viewed from lateral side. The recess 81 formed in the lower rigid sail 4A has a triangular crosssection for closely receiving the extension 80.

The lower rigid sail 4A is supported at its base end portion by a mast 2 or a sail supporting base.

As in the case of the preceding embodiments, a winding shaft 82 for winding up the flexible sail 13 is disposed above a boom 8 which is located at one side of the sail supporting base 2.

Hereinafter, the operation of the hybrid sail apparatus of this embodiment will be explained with reference to the drawings.

For instance, as will be seen from Figs. 24 and 25, a wire 86 is wound round a pulley 83 provided on the end of the extension 80 of the upper rigid sail 48, a pulley 84 provided in the lower rigid sail 4A and a take-up device 85 mounted in the sail supporting base 2. As the wire is taken up and paid off by the taking up device 85, the upper rigid sail 4B is swung with respect to the lower rigid sail 4A around the hinge 87 in the direction of an arrow M, so that the upper rigid sail 4B is turned sideways with respect to the lower rigid sail 4A as will be seen from Figs.

24 and 25.

In the hybrid sail apparatus of this embodiment, the rigid sail 4 is divided at its mid portion into the lower rigid sail 4A and the upper rigid sail 4B which are connected to each other through a hinge 87 provided on one side surface of the rigid sail 4, so that the upper rigid sail 48 can be turned sideways with respect to the lower rigid sail 4A in one lateral direction. This arrangement permits the use of a hinge having a simple construction and a safe turning or bending of the rigid sail 4.

Moreover, since the rigid sail 4 can be bent in a manner described, the height of the hybrid sail apparatus can be reduced to permit the ship to move in the harbour or channel averting from shore structures. The hinge line in this embodiment of the invention is preferably mounted in conformity with the lateral side of the rigid sail or outside of the same. By so doing, it is possible to further simplify the construction of the hinge portion of the rigid sail.

In the described embodiment of the invention, the rigid sail 4 is divided at its mid portion into two halves along a plane including a chordal line and two halves are connected to each other through the hinge 87 so that one half may be turned sideways. This, however, is not exclusive and the rigid sail 4 may be divided into three or more sections to permit a further reduction in the height of the rigid sail apparatus in the folded state.

Figs. 26 and 27 are a front elevational view and a side elevational view, showing the detail of the hybrid sail apparatus having foldable construction.

A main post 91 extends upright from the deck 1. The lower rigid sail 4A of the rigid sail 4 is rotatably carried by the main post 91. The lower rigid sail 4A is provided at its central portion with a tubular body 92 which is supported by the main post 91 through a bearing. The lower rigid sail 4A has a plurality of aerofoil-shaped ribs 93 (Fig. 31) extending at a right angle to the tubular body 92, and metallic sheets secured to the outer surfaces of the ribs 93 so as to form the lower rigid sail 4A having the aerofoil-shaped cross-section. A recess 81 is formed in the upper central portion of the lower rigid sail 4A. The recess is tapered such that its depth is greatest at the upper end of the lower rigid sail 4A and gradually decreased towards the lower side.

As will be seen from Fig. 30, a multiplicity of ribs 94 are formed behind the recess 81, and a portion of the hinge 87 is formed on the ends of the ribs 94.

The upper rigid sail 48 has a construction similar to the lower rigid sail 4A. Namely, the upper rigid sail 48 has a central tubular body 95 and a plurality of aerofoil-shaped ribs extending perpendicularly to the tubular body 95 as shown in Fig. 28. Metallic sheets are secured to the outer surfaces of these ribs. A part of the hinge 87 is provided at the lower end of the tubular body 95 to mate with the part of the hinge 87 provided on the lower rigid sail 4A. An extension 80 having the thickness gradually decreased towards the end is formed to extend from the central portion of the lower end of the upper rigid sail 4B. The extension is sized and shaped to closely fit in the recess 81 formed in the lower rigid sail 4A.

Detail of construction of rigid sail The detail of the rigid sail will be explained hereinunder.

Figs. 28 to 31 are sectional views showing the internal structure of the rigid sail having aerofoilshaped cross-section. More specifically, Fig. 28 shows a rib provided at an intermediate portion of the rigid sail. Ribs 96 and 96A made of iron sheets are welded to both sides of the tubular body 95. Thin metallic sheets 97, which may be "colored iron sheets coated with corrosion resistance paint" are secured to cover the outer surfaces of these ribs to provide the aerofoilshaped cross-section of the rigid sail.

Reinforcement members 98 are mounted as desired at the inner side of the aerofoil-shaped rigid sail.

A rib 96B shown in fig. 29 is the rib which is adapted to be provided at the end of each section.

In contrast to the ribs intended for use in other portions, the rib 96B has a comparatively large area to bear a cdmparatively large force. As will be seen from Fig. 26, ribs 96 and 96A shown in Fig. 28 are arranged between adjacent ribs 96B.

Fig. 30 shows the shape of the folding part. A recess 81 is formed in one side of the lower rigid sail 4A so as to receive the extension 80 of the upper rigid sail 4B. A plurality of ribs 94 and 94A for reinforcement are provided behind the recess 81 and in the extension 80.

Referring now to Fig. 31 showing the crosssection of the lower rigid sail 4A, the lower rigid sail 4A has the tubular body 92 having a diameter greater than that of the main post 91 so as to receive the latter through the medium of a bearing which is not shown. Ribs 93 are extended perpendicularly to the tubular body 92.

Further, as shown in Fig. 26 and similar to ribs 96B in the upper rigid sail 48, a rib 93A having a relatively large area is disposed in each section in the lower rigid sail 4A.

Fig. 32 shows the construction for securing the metallic sheets which provides the aerofoilshaped outer configuration of the rigid sail. Ribs 100 made of shaped steel are welded to the ends of the ribs 96. The metallic sheets 97 are fixed by screws 101, rivets or, as required, by welding to the surfaces of the ribs 100. An ordinary fixing construction may employ an ordinary method.

The construction of the folding structure will be explained hereinunder.

Referring to Figs. 33, 34 and 35 showing the detail of the folding construction of the rigid sail, the tubular body 95 has an enlarged end to one side of lower end of which provided is a hinge 87.

The extension 80 is extended in the longitudinal direction of the upper rigid sail 48. On the other hand, ribs 94 constituting the whole or a part of the recess 81 are provided in the lower rigid sail 4A. The tubular body 92 is extended from the lower end of the ribs 94.

The extension 80 of the upper rigid sail 4B and the recess 81 for receiving the extension 80 are the portions which do not provide a circular crosssection, so that these portions are formed by combining a multiplicity of ribs 94 and 94A made of thin metal sheets as shown in Figs. 34 and 35.

Fig. 35 shows the basic structure of the ribs constituting the extension 80 and the recess 81.

The tubular bodies 92 and 95 extending through the upper rigid sail 4B and the lower rigid sail 4A may have constant diameters or a so-called tapered shape with their diameters increasing towards the lower ends.

Fig. 36 shows a cross-section taken along the line X-X in Fig. 35. It will be seen that a multiplicity of ribs 94 and 94A are provided for reinforcement in the extension 80 of the upper rigid sail 4B and in the portion of the lower rigid sail 4A constituting the recess 81 for receving the extension 80.

Preferably, the tubular bodies 92 and 95 are formed by bending high-tension steel sheets into cylindrical forms and then welding the abutting ends along the lengths thereof.

The cylindrical form made of the high-tension steel offers an advantage that the welding can be made linearly along a straight line at one side of the cylinder. The cylindrical form of the tubular body is advantageous particularly when hightension steel is used as the material, because the high-tension steel has a tendency to suffer cracking as a result of welding or a deterioration of the strength in the welded portion resulting in a lowered fatigue limit.

For the same reasons, it is preferred that the number of ribs welded to the tubular body is diminished as much as possible and to reduce the area of the welding.

Preferably, a steel sheet having superior corrosion resistance and high mechanical strength, commercially available as "colored steel sheet" is used as the steel sheets constituting the aerofoil profile of the rigid sail. An example of such steel sheets is the "Frolbond" produced by Nittetsu Kenzai Kogyo K. K., Chuo-ku, Tokyo, Japan.

According to the invention, the rigid sail of the hybrid sail apparatus is composed of a tubular body, ribs arranged at both sides or around the tubular body and corrosion resistant metallic sheets as the surface members secured to the outer surfaces of the ribs thereby to form the aerofoil-shaped profile of the rigid sail. The rigid sail, therefore, can be produced easily and the weight of the same is reduced advantageously.

Claims (20)

Claims

1. A hybrid sail apparatus composed of a rigid sail having a substantially flat cross-section and a flexible sail made of a flexible material, wherein said rigid sail is rotatably supported by a mast or a sail supporting base fixed onto a deck while said flexible sail has lower end rotatably supported by a boom extended laterally from the lower end of said rigid sail, the angles of said rigid sail and said flexible sail being adjustable to any desired angles.

2. A hybrid sail apparatus according to claim 1 wherein said rigid sail has an aerofoil-shaped cross-section.

3. A hybrid sail apparatus according to claim 1, wherein said rigid sail is provided at its center with a tubular body to which fixed are a multiplicity of ribs, and metallic sheets secured to the outer surfaces of said ribs so as to provide a substantially aerofoil-shaped profile of said rigid sail.

4. A hybrid sail apparatus according to claim 1, wherein said rigid sail has a substantially oval shape.

5. A hybrid sail apparatus having, in combination, a rigid sail of a substantially flat cross-section and a flexible sail made of a flexible material and continuing from said rigid sail, characterized by comprising a slat projectable from the front upper side of said rigid sail.

6. A hybrid sail apparatus according to claim 5, wherein said slat is provided on the front side of said rigid sail through supporting members, said slat being divided into two parts along its length at the mid portion thereof, said two parts being connected to each other by a hinge, the portion of said slat near the connection being supported by said supporting members so that said slat being adapted to be inclined to the port and starboard sides as desired and said two parts of said slat being adapted to be swung to approach the surfaces of said rigid sail.

7. A hybrid sail apparatus according to claim 5, wherein two slats are provided in such a manner as to be able to project forwardly from both surfaces of said rigid sail and to be housed onto the surfaces of said rigid sail.

8. A hybrid sail apparatus according to claim 5, wherein said hybrid projectable from the front side of said rigid sail and adapted to be housed onto the front side of said rigid sail is guided by a rail.

9. A hybrid sail apparatus according to claim 1, wherein said flexible sail is provided with a winding shaft, which is provided in the vicinity of the rear end of said rigid sail.

10. A hybrid sail apparatus according to claim 9, wherein said rigid sail is hollow and is provided with a longitudinally extending slit at the rear side thereof, said winding shaft for winding up said flexible sail being vertically disposed in said rigid sail, said flexible sail being extended through said longitudinally extending slit.

11. A hybrid sail apparatus according to claim 1 or 5, wherein said winding shaft for winding up said flexible sail is supported at its upper portion by the top portion of said rigid sail while the lower portion of the same is supported in such a manner as to be movable along an arcuate boom extended laterally of said rigid sail.

12. A hybrid sail apparatus according to claim 1 or 5, wherein the winding shaft for winding up said flexible sail is provided on a boom extended laterally from said rigid sail.

13. A hybrid sail apparatus according to claim 12, wherein said winding shaft for winding up flexible sail is composed of a pair of pinch rollers.

1 4. A hybrid sail apparatus according to claim 1 or 5, wherein each of said rigid sail and said boom is provided with means for adjusting the angle thereof.

1 5. A hybrid sail apparatus composed of a rigid sail having a substantially flat cross-section and a flexible sail made of a flexible material, wherein said rigid sail is divided at its mid portion into an upper rigid sail and a lower rigid sail which are connected to each other by a hinge, said lower rigid sail being standing upright and rotatably supported by a sail supporting base provided on the deck, while said upper rigid sail can be turned sideways with respect to said lower rigid sail so as to reduce the height of said rigid sail as desired.

1 6. A hybrid sail apparatus according to claim 16, wherein said lower rigid sail is provided in its one side with a longitudinal recess which is adapted to receive an extension formed on said upper rigid sail.

1 7. A hybrid sail apparatus according to claim 17, wherein the depth of said recess is greatest at the foldable joint portion of said rigid sail and is gradually decreased towards the lower end of said lower rigid sail, while said extension on said upper rigid sail has a thickness which is gradually decreased towards the end thereof.

1 8. A hybrid sail apparatus according to claim 16, wherein said extension has a weight which balances a part of whole of the weight of said rigid sail.

1 9. A hybrid sail apparatus according to claim 16, wherein said upper rigid sail can be elevated and lowered with respect to said lower rigid sail by means of a wire wound round pulleys provided on said extension of said upper rigid sail and on said lower rigid sail.

20. A hybrid sail apparatussubstantially as hereinbefore described with reference to and as shown in the accompanying drawings.