GB2063804A - Wind powered water borne vessel - Google Patents

Abstract

A water-borne vessel is provided with a plurality of wind-powered units (18) ranged in rows along the axis of the vessel (11) and having transmission systems able to transmit drive to respective longitudinally extending drive shafts (13, 14) to propulsion screws (15, 16). Infinitely variable gearing transmission systems and slipping unidirectional clutches are provided to accommodate variations in the wind speed and differences between this and the rotational speed of the drive shafts (13, 14). Wind direction sensors provide signals for automatic directional control of the units (18) so that these always face into the wind. <IMAGE>

Description

SPECIFICATION Wind powered water borne vessel The present invention relates to a wind-powered water borne vessel able to derive at least a part of its propulsion from the wind.

The problem of fuel shortages and increased fuel costs has led to increasing interest in the possibility of re-introducing some form of wind power for water-borne vessels.

Conventional sails are both large and inefficient, require substantial manning levels above those at which the economy of wind power can be realised, and in addition are difficult to manage and have the added problem of being of restricted use when running into the wind.

Although in vessels propelled purely by the wind it is common practice to "beat" that is to follow a zig-zag path when working up wind, this is not really an economic possibility for commercial vessels since the value of the vessel depends to a large extent on the number of different cargoes it can carry in a given period of time and the loss of time due to adverse weather conditions leading to extended journey times is inadmissable.Even vessels having auxiliary sails, that is having a main propulsion by screw or paddle, and having sails which enable the vessel to take advantage of any favourable winds, do not entirely solve the problem due to the fact that the windage of the spars and other supporting gear for the sails offers added resistance when driving upwind under the motor alone so that although a certain advantage is obtainable in downwind and crosswind situations, the upwind performance is correspondingly reduced to an extent which significantly reduces the advantage obtained.

The present invention seeks to provide a wind powered water borne vessel in which the above problems are at least reduced if not entirely eliminated, and to provide a vessel in which the propulsion may be obtained entirely from the wind, or partly from the wind and partly from a fuelled engine or motor allowing the vessel to travel in any direction, regardless of the direction of the wind, and derive at least part of its propulsion from the wind.

According to the present invention a water borne vessel having a screw or paddle propulsion system is provided with means by which at least part of the propulsion power for the screw or paddle can be derived from at least one auxiliary wind-powered unit mounted on the hull of the vessel.

The vessel may, of course, have a plurality of such wind-powered units, preferably spaced along the length thereof in one or a plurality of axial rows.

The vessel may, of course, be powered solely by the wind-powered units driving the screw or paddle, or there may be provided an auxiliary motor for driving the screw or paddle in low wind conditions when the wind-powered units will not provide sufficient drive for the vessel. Alternatively, the vessel may be powered by a fuelled motor and the wind powered units be arranged to serve as auxiliary elements to provide power assistance to the motor.

The wind-powered units may be of one of a number of different forms, for example they may be in the form of windmill type fans having radial blades projecting from a hub member or shaft rotatable about a horizontal axis. In such a case the hub member or shaft must also be turnable about a vertical axis to direct the fan into the wind to obtain the most efficient power drive. The wind-powered units may, alternatively, each comprise a pair of windmill-type radial blade fans mounted on a common horizontal shaft (for example by means of respective sleeves) with power take off being effected from a point along the shaft between the two fans. The two fans may rotate in the same direction, or may be counter rotating and this latter arrangement has particular advantages for driving a vertical transmission shaft by means of respective bevel gears one from each fan.In this respect it is preferred that the transmission of power from the fans to the screw or paddle propulsion system is effected by means of bevel gears driving transmission shafts which are interconnected with a longitudinally extending drive shaft, or a plurality of such drive shafts in the case of the system comprising more than one row of fans.

Alternatively, however, the transmission of propulsion from the fans to the longitudinally extending drive shaft or shafts may be effected by chain or belt transmissions which, although more cumbersome, have the advantage of reduced frictional losses.

If the vessel has two or more rows of windpowered units ranged along the length of the vessel, it is preferred that the vessel may be equipped with twin screws or paddles, each driven by a respective longitudinally extending drive shaft arranged one for each row of fans.

In addition to the fan type described above, that is the axial flow horizontal axis type having radially extended aerofoil section blades, the fan may be of the axial blade type with vertical axis. Such a fan has the advantage of not requiring any swivelling arrangement to accommodate variations in the direction of the wind since, having a vertical axis, it is not sensitive to the direction from which the wind arrives. In such a case the vertical blades may be substantially straight parallel blades or may be the curved blades of the socalled Darreus rotor. Even a vertical axis Savonius rotor may be employed although since the efficiency of such rotors is rather low other types are presently preferred.

One problem which is envisaged with a system incorporating a plurality of fans, whether arranged in one or more rows, is that the wind speed and direction may vary either spatially or temporally along the length of the row giving rise to inefficiences in the transmission of power if each fan is rigidly connected by a transmission system to the drive shaft.

To overcome this problem it is proposed that one or more unidirectional clutch assemblies may be provided in the transmission system preferably one between each fan and the common drive shaft, perhaps at a junction thereof. Such unidirectional clutch arrangements would act to accommodate differences in the speeds of different fans attached thereto so that the fastest fan or fans will drive the common drive shaft. This arrangement would have the slight disadvantage, however, that the slower fans would not be transmitting full power to the shaft, and in a more sophistacated embodiment there is provided a variable gearing arrangement between the or each fan and the or the respective drive shaft whereby to drive the shaft at a predeterminable speed despite fluctuations in the wind speed (and correspondingly despite differences in the speeds of the fans along the length of the row).Such a variable gearing arrangement would require to have automatic operation including a wind speed sensor for each fan, and a shaft speed sensor from the data of which a suitable gearing ratio for any instant in time can be selected. Of course, for such an arrangement an infinitely variable gearing system is required rather than one having a plurality of discrete ratios as are more conventionally employed. Such infinitely variable gearing arrangements are known as such and will not be described in detail here.

Another problem which is envisaged is that of variable efficiency of a fan in different wind speeds. To accommodate this problem it is proposed that the fans will have variable pitch blades which can be set to accommodate variations in the wind speed and, in particular, can be set to feather (i.e. present the minimum forward resistance) in the event of very high (gale force) winds where the wind resistance of the superstructure of a vessel must be minimised.

The fans may have any suitable number of blades from one upwards in dependence on the most efficient design criteria for the size of fan being constructed. It is envisaged that this arrangement will be of particular value, for example, on very large vessels such as oil tankers which already have extremely low profile and clear decks and would be emi nently suitable for the provision of such wind powered assistance since the control superstructure is generally placed to the rear of the vessel.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accom panying drawings, in which: Figure 1 is a plan view of a vessel equipped with wind-powered screw assistance units in accordance with the invention; Figure 2 is a side view of the vessel showing the wind-powered units in position: and Figure 3 is a schematic cross sectional view of one of the wind-powered units of the vessel shown in Figs. 1 and 2 illustrating its construction and connection to the propulsion system.

Referring now to the drawings there is shown a vessel, generally indicated 11 having a conventional fuel powered motor arrangement 1 2 mounted amidships and driving twin drive shafts 13, 14 leading to respective screws 1 5, 1 6 for propulsion of the vessel. As can be seen in Fig. 2 the control superstructure of the vessel, generally indicated 17, is mounted to the rear or aft portion of the vessel and there are five wind-powered units 18 mounted in each of two longitudinal rows one on each side of the vessel.

Each wind-powered unit 1 8 comprises a fan arrangement of two counter rotating fans 19, 20 mounted on respective sleeves 21, 22 rotatable on a common shaft 23 which supports a plurality of stator blades 24 for guiding the air flow between the two rotor fan systems 19, 20. Surrounding the fan is a shroud 25 which is mounted on a vertical axis ring bearing 26 supported on the deck 27 of the vessel 11. In this way the whole fan arrangement can be turned about a vertical axis to face directly into the wind from whichever direction this comes. Moreover, the drive arrangement from the fans, as will be seen more particularly below, is so arranged that the fan can be continuously rotated in one direction to follow variations in the wind without causing any problems in the drive trans mission.

Each of the sleeves 21, 22 carries a respective bevel gear 28, 29 on the end thereof facing the other fan (that is on the inner end thereof nearer the stator 24), and these two bevel gears 28, 29 mesh with a vertical axis bevel gear 30 carried at the upper end of a vertical transmission shaft 31 which leads down through the centre of the ring bearing 26 to an infinitely variable gear box 32 the output shaft 33 from which carries a bevel gear 34 meshing with a horizontal axis bevel gear 35 carried via a unidirectional clutch 36 on a horizontal axis longtudinally extending drive shaft such as the drive shaft 13 or 14 shown in Fig. 1, which drive shaft is also driven by the fuelled motor system 12 when this is running.

As can be seen in Fig. 3, the infinitely variable gearbox 32 is controlled by a control device 37 receiving input signals from a wind speed sensor 38 located at a vertical height corresponding to the axis of the fan rotors 19, 20, and a shaft speed sensor 39 attached to the longitudinal drive shaft 13, 14. In depen dence on the variations between these two signals the infinitely variable gearbox 32 is adjusted so that the ratio chosen accommodates the difference in rotational speed between the vertical axis shaft 31 and the horizontal main drive shaft 13, 14 with the maximum transmission of power. The unidirectional clutch 36 allows for overrun of the fan in the event of sudden gusting of the wind, and preferably this clutch is a slipping clutch so that at least a proportion of the drive is transmitted to the shaft 13, 14 even in overrun conditions.

To ensure that the fan units 1 8 all face into the wind there is provided a wind direction sensor located at some suitable point in advance of the axis of the common shaft 21, the wind direction sensor being indicated by the reference numeral 40. The output signals from the wind direction sensor 40 are fed to a motor 41 which drives the ring bearing 26 to rotate the shroud 25 and the whole fan unit 18 to maintain the axis of the common shaft 21 directly into the wind.

Although a single wind direction sensor could be provided at a certain location in the vessel, for example at the bow, and all the fan units 1 8 driven to face in the same direction from this, the variations in wind direction along the length of the vessel would mean that not all the fan units 1 8 were in fact facing directly into the wind and therefore although this would involve a greater capital expense it is preferred that each fan unit 1 8 has its own individual wind direction sensor 40 and motor 41 for finely adjusting each respective fan unit to face directly into the wind which it alone is experiencing.

The propulsion provided by the fan units to the main drive shafts 13, 14 will in many wind conditions be sufficient to drive the screws 1 5, 1 6 without requiring the assistance of the motor 1 2 although this will be required in conditions, for example, when heading directly into the wind since in these conditions each fan unit 1 8 will be facing along the axis of the vessel and will, at least to some extent, be located in the "wind shadow" of the fan in front so that the fans to the rear will not be providing the maximum amount of power possible. In circumstances where fuel economy is of paramount importance it may even be advantageous to head slightly off the wind so that the fan units 1 8 can be inclined slightly to reduce the "wind shadow" effect.

In another embodiment (not shown) the shroud 25 projects forwardly from the front fan 1 9 and flares outwardly to an enlarged mouth which serves to increase the "catchment area of the fan. The flared portion also serves to provide an intake ram effect increasing the wind speed experienced by the fan.

It will also be appreciated that the windpowered units 1 8 of the present invention are not necessarily restricted to two fans. There may be advantages in having only one fan, or a plurality of fans in tandem may be provided in the manner of a compressor.

Claims (14)

1. A water borne vessel having a screw or paddle propulsion system, in which at least part of the propulsion power for the screw or paddle is derived from at least one auxiliary wind-powered unit mounted on to the hull of the vessel.

2. A vessel as claimed in Claim 1, in which the vessel has a plurality of windpowered units.

3. A vessel as claimed in Claim 1 or Claim 2, in which the vessel is powered solely by the wind-powered units.

4. A vessel as claimed in Claim 1 or Claim 2, in which the vessel is powered by a fuelled motor and the wind-powered units serve to provide power assistance.

5. A vessel as claimed in any preceding Claim, in which the wind-powered units are in the form of windmill type fans.

6. A vessel as claimed in any preceding claim, in which the wind-powered units each comprise a pair of windmill type fans mounted on a horizontal shaft and power take-off from the shaft is effected from a point between the fans.

7. A vessel as claimed in any preceding Claim, in which the transmission of power from the fans to the screw or paddle propulsion system is effected by means of bevel gears driving a longitudinally extending drive shaft.

8. A vessel as claimed in any preceding Claim, in which there are two rows of windpowered units ranged along the vessel one on each side thereof and the vessel is equipped with twin screws or paddles each driven by a respective longitudinally extending drive shaft.

9. A vessel as claimed in any preceding claim, in which the fan or fans is or are of the axial flow horizontal axis type having radially extending aerofoil section blades.

10. A vessel as claimed in any of Claims 1 to 4, in which the fan or fans is or are of a type having generally axially extending blades.

11. A vessel as claimed in Claim 10, in which the axis or axes of the wind-powered units extends or extend substantially vertically.

1 2. A vessel as claimed in any of Claims 7 to 11, in which the or each longitudinally extending drive shaft has one or more unidirectional clutch to accommodate differences in the speeds of different fans attached thereto.

1 3. A vessel as claimed in any of Claims 7 to 12, in which there is provided a variable gearing arrangement between the or each fan and the or the respective drive shaft whereby to drive the shaft at a predetermined speed despite fluctuations in the wind speed.

14. A vessel as claimed in any of Claims 5 to 13, in which the fans have variable pitch blades to accommodate variation in the wind speed.

1 5. A vessel as claimed in any preceding Claim, in which there are more than one row of wind-powered units each driving a respective drive drive shaft the drive shafts all being connected to drive a single drive screw.

1 6. A vessel substantially as hereinbefore described with reference to the accompanying drawings.

1 7. An auxiliary drive system for a waterborne vessel having a screw or paddle propulsion system, including one or more windpowered units mounted on the hull of the vessel and connectable to the or a screw or paddle propulsion system.

1 8. An auxiliary drive system as claimed in Claim 7, in which the or each said screw or paddle is separate from the screw or paddle of the vessel's primary propulsion system.

1 9. A vessel as claimed in Claim 1 0 or Claim 11, in which the or each wind-powered unit is a Darrieus rotor.