WO2000034118A1 - A marine propulsion unit and a boat having a marine propulsion unit - Google Patents
A marine propulsion unit and a boat having a marine propulsion unit Download PDFInfo
- Publication number
- WO2000034118A1 WO2000034118A1 PCT/GB1999/004091 GB9904091W WO0034118A1 WO 2000034118 A1 WO2000034118 A1 WO 2000034118A1 GB 9904091 W GB9904091 W GB 9904091W WO 0034118 A1 WO0034118 A1 WO 0034118A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- propeller
- propulsion unit
- boat
- cowl
- gas
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
- B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
- B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
- B63B1/32—Other means for varying the inherent hydrodynamic characteristics of hulls
- B63B1/34—Other means for varying the inherent hydrodynamic characteristics of hulls by reducing surface friction
- B63B1/38—Other means for varying the inherent hydrodynamic characteristics of hulls by reducing surface friction using air bubbles or air layers gas filled volumes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
- B63B39/06—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water
- B63B39/061—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water by using trimflaps, i.e. flaps mounted on the rear of a boat, e.g. speed boat
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H1/00—Propulsive elements directly acting on water
- B63H1/02—Propulsive elements directly acting on water of rotary type
- B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
- B63H1/14—Propellers
- B63H1/28—Other means for improving propeller efficiency
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H11/00—Marine propulsion by water jets
- B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
- B63H11/10—Marine propulsion by water jets the propulsive medium being ambient water having means for deflecting jet or influencing cross-section thereof
- B63H11/107—Direction control of propulsive fluid
- B63H11/117—Pivoted vane
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
- B63H25/06—Steering by rudders
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H1/00—Propulsive elements directly acting on water
- B63H1/02—Propulsive elements directly acting on water of rotary type
- B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
- B63H1/14—Propellers
- B63H1/28—Other means for improving propeller efficiency
- B63H2001/286—Injection of gas into fluid flow to propellers, or around propeller blades
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T70/00—Maritime or waterways transport
- Y02T70/10—Measures concerning design or construction of watercraft hulls
Definitions
- the present invention relates to a marine propulsion unit and, in particular, to a marine propulsion unit that can be easily attached to or removed from a boat.
- the invention also relates to a marine propulsion unit provided with a blade for directing the thrust of a propeller, and also to a marine propulsion unit having means for inducing cavitation on initial turning of the propeller.
- the present invention also relates to a boat that is equipped with such a propulsion unit, or that is able to receive such a propulsion unit.
- the present invention also relates to a cowl for such a propulsion unit.
- marine propulsion unit is the conventional outboard motor.
- the principal components of an outboard motor are a diesel or petrol engine, a propeller mounted on a propeller shaft, and a drive train or drive shaft for transmitting the output torque of the engine to the propeller shaft.
- an outboard motor is suspended from the back of a boat so that the propeller is below the water level and the engine is above the water level.
- An outboard motor is usually attached to a boat in such a way that it can pivot about a substantially vertical axis.
- vertical axis is meant an axis that is vertical when the boat is in its normal orientation, for example at rest in a calm sea.
- horizontal axis is meant an axis which is horizontal when the boat is in its normal orientation, for example at rest in a calm sea.
- Outboard motors can be heavy - for example, with a mass of 50 - 200kg - so that they have large moments of inertia. It is therefore relatively difficult to rotate an outboard motor in order to steer a boat. This means that there is a significant response time before a boat will change course. This is the case even where the outboard motor is rotated by means of a power steering, or power-assisted steering, arrangement. It is usual for a boat to be provided with means for trimming the boat, to take account of the distribution of the load in a boat. In a boat fitted with a conventional outboard motor, the boat is generally trimmed by altering the angle of the propeller shaft relative to a horizontal axis, so as to vary the angle between the propeller thrust and the horizontal. This is done by rotating the entire outboard motor about a horizontal axis. Since it is necessary to rotate the entire outboard motor so as to trim the boat, the same problems occur in trimming a boat as occur in steering.
- a jet outboard motor is similar in appearance to a conventional outboard motor, except that the propeller of a conventional outboard motor is replaced by a jet.
- the boat is driven by the thrust from the jet, rather than by thrust generated by rotation of a propeller.
- a jet outboard motor is generally suspended from the back of a boat in the same manner as a conventional outboard motor.
- the boat is steered in a similar manner to a boat fitted with a conventional outboard motor, by rotating the jet outboard motor about a substantially vertical axis.
- the trim of a boat fitted with a jet outboard motor is adjusted in a similar manner to a boat fitted with a conventional outboard motor, by rotating the jet outboard motor about a horizontal axis.
- Small boats are commonly powered by diesel outboard engines typically having power outputs of up to around 50hp. If a greater power output is required, a conventional stern drive propulsion unit can provide a power output of around 150hp or greater, and a jet outboard motor will provide a horsepower of greater than 300hp. It can thus be seen that there is a gap in the range of power outputs provided by today's commercially available propulsion units, in the range 50 to 150hp. While this gap can sometimes be filled by using two outboard motors - for example, using two 50hp outboard motors to obtain a total power output of lOOhp - this is not an ideal solution. For one reason, some boats physically cannot be fitted with two outboard motors.
- Another disadvantage is that, if a boat is provided with two outboard motors, their full combined power output may be required only for short periods because maximum power is often only required at specific times such as, for example, when a boat is accelerating from rest to its cruising speed.
- the provision of two outboard motors is thus an expensive way of achieving greater initial acceleration.
- outboard motors are usually available only up to around 50hp, the maximum power output that can be obtained from two outboard motors is around lOOhp. This still leaves a gap between lOOhp and 150hp.
- An outboard motor is inflexible in its positioning, since it must be located at the stern of a boat. If it is desired to replace an existing outboard motor, it is advisable to replace it with an outboard motor of approximately the same weight, as otherwise the balance and performance of the boat can be adversely affected. This severely limits the choice of a possible replacement outboard motor, and makes it very difficult to replace an outboard motor with a significantly more powerful outboard motor, since a more powerful outboard motor will almost certainly be heavier than the existing outboard motor. A jet outboard motor is again suspended from the stern of a boat, and thus suffers from this disadvantage of the conventional outboard motor.
- a first aspect of the present invention provides a marine propulsion unit comprising: a propeller shaft adapted to be coupled to a drive source; a propeller mounted on the propeller shaft; and a cowl disposed under the propeller and extending at least partially around the circumference of the propeller.
- the propeller shaft may be mounted on the cowl.
- the propulsion unit can be mounted on a boat simply by securing the cowl to the boat, and connecting the propeller shaft to the drive source. Since the drive source itself does not form part of the propulsion unit, the drive source can be positioned at any desired location in the boat. This means that the weight of the drive source is not necessarily concentrated at the stern of the boat, and it is easier to obtain good balance.
- the provision of the cowl, which extends at least partially around the circumference of the propeller promotes the flow of water past the propeller, and thus increases the thrust provided by the propeller.
- the cowl has the further advantage that it provides physical protection for the propeller.
- a propulsion unit according to this aspect of the present invention can be mounted on any boat having a suitably shaped hull.
- a second aspect of the present invention provides a marine propulsion unit comprising: a propeller shaft adapted to be coupled to a drive source; a propeller mounted on the propeller shaft; and a first blade provided downstream of the propeller and mounted for rotation about a first axis for directing the thrust of the propeller.
- the boat is steered simply by rotating the first blade about its axis.
- the blade is much lighter than an outboard motor, and has a much lower moment of inertia. It is therefore much easier to control the rotation of the blade, and hence the direction of thrust.
- the response time of the blade is also reduced compared to the response time of an outboard motor.
- a third aspect of the present invention provides a marine propulsion unit comprising: a propeller shaft adapted to be coupled to a drive source; a propeller mounted on the propeller shaft; and a means for introducing gas upstream of the propeller on application of an initial torque to the propeller shaft so as to promote cavitation on initial turning of the propeller and thereby increase the initial propulsion force.
- a propulsion unit according to this aspect of the invention has an increased power output on starting, and will therefore produce increased acceleration of the boat to which it is applied from rest. Such a propulsion unit can therefore be used in applications in which a greater initial power output is required than is available at a comparable cost by use of a conventional propulsion unit. The cost of providing the gas supply is much smaller than providing a second motor.
- a fourth aspect of the present invention provides a boat having a propulsion unit according to the first, second or third aspect of the invention.
- a fifth aspect of the present invention provides a boat having a recess provided in its hull, the recess being so dimensioned as to accommodate a marine propulsion unit according to the first, second or third aspect of the present invention.
- a sixth aspect of the present invention provides a cowl for a marine propulsion unit, the cowl being so dimensioned as to partially close a recess provided in the hull of a boat.
- Figure 1 is a schematic side view of a boat equipped with a propulsion unit according to an embodiment of the invention
- Figure 2 is a view of the stern of the boat of Figure 1;
- Figure 3 is a perspective view of the cowl of the propulsion unit of Figure 1;
- Figure 4(a) is a partial perspective view of a propulsion unit according to another embodiment of the invention.
- Figure 4(b) is a view of the stern of a boat equipped with the propulsion unit of Figure 4(a);
- Figure 5(a) is a partial perspective view of a propulsion unit according to another embodiment of the invention
- Figure 5(b) is a view of the stem of a boat equipped with the propulsion unit of Figure 5(a);
- Figure 6(a) is a partial side view of a boat equipped with a propulsion unit according to another embodiment of the invention.
- Figure 6(b) is a partial side view of a boat equipped with a propulsion unit according to another embodiment of the invention.
- Figure 7 is a partial side view of a boat equipped with a propulsion unit according to another embodiment of the present invention.
- Figure 8(a) is a schematic side view of a boat equipped with a propulsion unit according to another embodiment of the invention.
- Figure 8(b) is a partial enlarged view of the propulsion unit of Figure 8(a);
- Figure 9 is a partial side view of a boat having a propulsion unit according to another embodiment of the invention.
- Figure 10 is a partial perspective view of a propulsion unit according to another embodiment of the invention.
- Figure 11 is a partial perspective view of a propulsion unit according to another embodiment of the invention.
- Figure 12 is a view of the stem of a boat having two propulsion units according to the present invention.
- Figure 13 is a schematic cross-sectional view of a boat equipped with a marine propulsion unit according to an embodiment of the invention
- Figure 14 is a schematic view of the stem of the boat of Figure 13;
- Figure 15 is a view of the stem of a boat equipped with a marine propulsion unit according to a modified embodiment of the invention.
- Figure 16 is a schematic cross-sectional view of a boat equipped with a marine propulsion unit according to a further embodiment of the present invention.
- Figure 17 is a view of the boat of Figure 16.
- Figure 1 is a schematic sectional view of a boat fitted with a propulsion unit according to a first embodiment of the present invention
- Figure 2 is a view of the stem of the boat of Figure 1.
- the boat 1 has a bottom which is provided with a recess 2. As is indicated by the broken line in Figure 1, the height of this recess is greatest at the stem of the boat, and decreases away from the stem. The height of the recess becomes zero around one-third to one-half of the length of the boat from the bow of the boat.
- the recess is preferably formed in the hull during the moulding process.
- the propeller 3 is mounted on a propeller shaft 4, which is mounted for rotation in bearings 5, 6.
- the forward bearing 5 is provided where the propeller shaft passes through the bottom of the boat, and is a watertight bearing.
- the rear bearing 6 is mounted in a support 7, the lower end of which is secured to the cowl and the upper end of which is secured to the boat at or near its stem.
- the support 7 may be a conventional "P-bracket".
- the propeller shaft 4 is connected to the output shaft 8 of a power unit 9.
- the power unit 9 is mounted inside the boat 1.
- the bottom of the recess is partially closed by a cowl 10.
- the cowl 10 acts so as to enclose the propeller in a "tunnel". Water enters the "tunnel" upstream of the propeller, as indicated by the arrows.
- the cowl 10 has two principal functions. Firstly, it provides physical protection for the propeller if, for example, the boat is grounded. Secondly, the cowl promotes the flow of water past the propeller, and thus increases the thrust provided by the propeller.
- the cowl 10 In order to remove the propulsion unit from a boat, all that is necessary is to release the cowl 10 from the boat, to separate the upper end of the support 7 from the boat, and to separate the propeller shaft 4 from the output shaft 8 of the power unit 9. (Although the joint between the propeller shaft 4 and the output shaft 8 is shown inside the boat - i.e., to the left of the bearing 5 in Figure 1 - the joint could alternatively be placed within the recess so as to facilitate disconnection and removal of the propeller shaft.)
- the hull of the boat is preferably provided with locating and/or fastening means to allow the cowl to be correctly positioned on the boat, and/or to enable the cowl to be secured to the boat.
- a further advantage of a propulsion unit according to this embodiment of the present invention is that it provides increased protection for divers.
- the cowl 10 serves to prevent divers from inadvertently coming into contact with the propeller and thereby suffering injury.
- propeller protection bars as disclosed in UK Patent No. 2 152 459 can be incorporated into the propulsion unit.
- FIG 3 is a perspective view of the cowl 10.
- the cowl is provided with abutments 11, 11.
- the abutments 11, 11 of the propulsion unit fit against corresponding abutments provided on the bottom of the boat, so as to position the propulsion unit relative to the boat.
- the propulsion unit can be secured to the boat by means of suitable fastening units (not shown) such as, for example, bolts or studs that protrude from the hull of the boat and pass through complementary holes 19 in the abutments 11, 11 of the cowl 10.
- the cowl is then secured in place with nuts.
- the cowl 10 can also be provided with means (not shown) for securing the lower end of the support 7 to the cowl.
- the cowl 10 shown in Figure 3 is provided with "vector vanes" 12. These are provided to spread the thrust of the propeller.
- vector vanes 12 are shown but, in practice, any number of vanes can be provided. If only a single vane 12 is provided, it should be placed on the centre line of the cowl 10. If more than one vane is provided, they should be arranged symmetrically about the longitudinal centre line of the cowl 10.
- vanes 12 It is possible for the vanes 12 to be omitted.
- Figures 4(a) and 4(b) An alternative embodiment of the invention is shown in Figures 4(a) and 4(b).
- Figure 4(a) is a partial perspective view of a boat having a propulsion unit according to this embodiment
- Figure 4(b) is a view of the stem of the boat of Figure 4(a).
- This embodiment differs from the embodiment of Figures 1 to 3 primarily in that a mdder plate 13 is provided on the boat 1.
- the mdder plate 13 is mounted downstream of the propeller, within the recess 2.
- the position of the propeller 3, and the axis 4' of the propeller shaft 4, are shown in broken lines in Figure 3(a).
- the mdder plate 13 is mounted on a mdder shaft 14 for rotation about the axis X-X shown in Figure 4(a).
- the upper end of the mdder shaft 14 is mounted in a watertight bearing 15 provided in the bottom of the boat, and the lower end of the mdder shaft is mounted in a bearing 15' provided in the cowl 10.
- the axis X-X is substantially vertical when the boat is in its normal orientation, for example in a calm sea.
- the boat is steered by rotating the mdder 13 about the axis X-X.
- the mdder is rotated such that the blade, as seen in plan view, is no longer parallel to the axis of the propeller shaft 4, and hence parallel to the thrust provided by the propeller, a sideways force will be developed on the mdder 13. This will cause the boat to turn.
- the embodiment of Figures 4(a) and 4(b) is generally similar to the embodiment of Figures 1 to 3.
- the support 7 is upstream of the propeller 3 in Figure 4(a) (whereas it is downstream of the propeller in Figure 1) it would be possible for the support 7 in Figure 4(a) to be downstream of the propeller.
- FIGS 5(a) and 5(b) A modified embodiment of the invention is illustrated in Figures 5(a) and 5(b). This embodiment is generally similar to the embodiment of Figures 4(a) and 4(b), except that trimming planes 16, 16' are provided in addition to the mdder plate 13. A further difference is that the support 7 of Figure 4(a) is replaced by a support 7 that is positioned downstream of the propeller 3.
- the trimming planes 16, 16' are mounted on a shaft 17 which is supported in a bearing (not shown) in the support 7.
- the shaft 17 can be rotated about the axis Y-Y. This axis is substantially horizontal and perpendicular to the axis X-X.
- the trimming planes 16 16' are fixedly mounted on the shaft 17. If the shaft 17 is rotated about the axis Y-Y, the trimming planes 16, 16' will rotate so that they are no longer parallel to the axis 4' of the propeller shaft 4 (not shown in Figure 5(a)). As a result, an upwards or downwards force will be exerted on the trimming planes, depending on whether they have been rotated upwards or downwards from their position as shown in Figure 5(a). This force will act to trim the boat in the water.
- Figure 5(a) illustrates one possible way in which the shaft 17 can be rotated.
- the shaft 17 is provided with lugs 18,18'. If the upper end of the lugs is moved to the left as shown in Figure 5(a), for example using a push-pull cable or other suitable mechanical actuator, the rear edges of the trimming planes will be elevated. Conversely, if the upper ends of the lugs 18,18' are moved to the right, then the rear edges of the trimming planes will be lowered.
- the boat is steered using the mdder plate 13.
- the mdder 13 will, however, not be very efficient at low speeds.
- the embodiments described above can be modified by the provision of an auxiliary steering means provided below the cowl 10. If no cowl 10 is provided, the auxiliary steering means should be provided so that they are protmde out from the recess 2.
- Figure 6(a) shows an embodiment in which auxiliary steering means are provided.
- the auxiliary steering means simply consist of an extension 13' of the mdder 13 that it extends below the cowl 10.
- the mdder shaft 14 extends through the cowl 10.
- An auxiliary mdder 13" is attached to the portion of the mdder shaft 14 that extends below the cowl 10.
- Figure 7 shows a modification of the embodiment of Figure 1.
- a nozzle 20 is provided in the bottom of the boat and opens at a point within the recess. Air can be conducted through this nozzle into the recess 2.
- the nozzle 20 is provided with a non-retum valve (not shown), to prevent water from passing upwards through the nozzle 20.
- Air will thus be introduced to the upper part of the area swept by the blades of the propeller 3. This air will induce cavitation at the propeller, and this will reduce the drag exerted by the water on the propeller. In consequence, the propeller will be able to rotate faster for a given torque, and thus provide a greater power output.
- the air can be supplied from any suitable source such as, for example, a compressor or a compressed air tank.
- a control means is provided to control the supply of air. Where the air is supplied from a compressed air tank, the control means can simply be a valve to shut off the supply of compressed air from the tank. If the compressed air is supplied by a compressor, the air supply could be controlled by providing a valve between the compressor and the nozzle 20. As an alternative, the supply of compressed air could be controlled by switching on, and shutting off, the compressor as required.
- the supply of air it is possible for the supply of air to be controlled automatically. This could be done, for example, by controlling the supply of compressed air on the basis of the speed of revolution of the propeller shaft 4 as measured by a suitable sensor.
- the control means would start supplying air when it detected that the propeller shaft had started to revolve, and would shut off the supply of air when the speed of revolution of the propeller shaft reached a pre-set value.
- the control means could control the supply of compressed air on the basis of other variables such as, for example, the speed of the boat.
- the supply of air could be controlled manually rather than automatically.
- the automatic control methods described above could be provided with a manual override.
- FIGs 8(a) and 8(b) A modified embodiment of the invention is illustrated in Figures 8(a) and 8(b). This embodiment differs from the embodiment of Figure 7 in that the support 7 for the propeller 3 is replaced by a support T which is positioned upstream of the propeller.
- the support T is secured to the bottom of the boat by any suitable means.
- the lower end of the support T can be secured to the cowl 10.
- the nozzle 20 is not provided in the bottom of the boat.
- the support T is provided with an internal air passage 22 as shown in Figure 8(b).
- the rear bearing 6 is disposed within the support 7'.
- the propeller shaft (not shown) is supported by the rear bearing 6, and the propeller 3 is carried on the propeller shaft 4.
- the position of the propeller 3 when it is installed is indicated in broken lines in Figure 8(b).
- Air is introduced into the inlet A of the internal air passage. Air leaving the internal air passage at the exit B is directed towards the upper part of the volume swept by the blades of the propeller 3, so as to induce cavitation.
- the internal air passage is shown as having only one exit in Figure 8(b), it is possible to provide more than one exit.
- an internal air passage is provided in a conventional P-bracket.
- the P-bracket is positioned up-stream of the propeller.
- the inlet A to the internal air passage 22 is in the upper face of the support. It is not, however, necessary to place the inlet in this location, and it could be provided elsewhere. In this case it would be necessary to transport air to the inlet; this could be done, for example, by providing a nozzle similar to nozzle 20 in the bottom of the boat, and connecting the nozzle 20 to the inlet A to the internal air passage of the support T using, for example, a pipe.
- FIG. 9 A further embodiment of the invention is illustrated in Figure 9.
- a pipe 23 is provided towards the bottom of the recess. Compressed air is introduced into the end C of the pipe 23, and leaves at the end D. The air leaving the end D of the pipe 23 is directed towards the propeller 3, so as to promote cavitation.
- the cowl 10 is shown in broken lines in Figure 9, for clarity.
- a further embodiment of the invention is shown in Figure 10.
- the pipe 23 is again provided towards the base of the recess.
- the end D of the pipe 23 is not open in this embodiment, however, but is connected to an annular tube 24.
- the annular tube is provided with a plurality of outlet holes 25 distributed around the circumference of the annulus.
- Air introduced into the tube 23 at its end C passes into the annular tube 24, and is directed towards the propeller by the outlets in the annular tube as indicated by the arrows.
- the air is directed primarily towards the outer portion of the area swept by the propeller blades - that is, towards the tips of the propeller blades.
- annular tube 24 could be provided with outlets only at its upper most portion. In this case, air would be directed only towards the radially outer portion of the upper part of the area swept by the blades of the propeller 3.
- cavitation is induced by directing compressed air towards the propeller.
- This air can be provided either by a compressor on board the boat, or by a compressed air reservoir.
- a compressed air reservoir is particularly convenient in the case of boats which carry a supply of compressed air for other purposes such as, for example, operating a self-righting mechanism.
- the means for delivering gas to the propeller are arranged such that rotation of the propeller tends to draw gas towards the propeller.
- the gas is fed into the recess, for example in any of the ways described above, and it is then drawn towards the propeller as a result of the suction caused by the rotation of the propeller.
- air could be provided from an inlet positioned above the waterline of the boat, for example in the stem or in a side of the boat.
- the air would be fed from the inlet to a nozzle such as the nozzle 20 of Figure 7, positioned in the base of the boat so as to feed air into the recess 2. If this arrangement is used, providing the nozzle in the side of the boat has the advantage that, once the boat starts to move, air will be forced through the inlet into the delivery system.
- a propulsion unit of the present invention may be provided with a gas introducing means to promote cavitation of the propeller in combination with a mdder plate and/or a trimming plane.
- Figure 11 shows a further embodiment of the invention, which combines the mdder 13 and trimming planes 16, 16' of Figure 5(a) with the pipe 23 and annular tube 24 for introducing air of Figure 10.
- FIG. 12 illustrates an embodiment of the invention in which two propulsion units are provided.
- the hull of the boat shown in Figure 12 is provided with two recesses 2, which are arranged side by side in the hull of the boat.
- a propulsion unit according to the invention is fitted in each recess.
- each propulsion unit is of the type illustrated in Figures 5(a) and 5(b).
- the boat of Figure 12 could be provided with any two propulsion units of the invention. It is, in principle, possible for the boat of Figure 12 to be fitted with two different propulsion units according to the invention.
- any of the propulsion units described hereinabove can be provided with an after-planing shoe.
- This can be formed integrally with the cowl 10, or it can be made as a separate item and secured to the cowl by any suitable means (for example, such as welding or using bolts).
- cowl 10 it is possible for the cowl 10 to be omitted from the embodiments described above, with all components of the propulsion unit being secured to the hull of the boat.
- Figures 13 and 14 show an embodiment in which the cowl 10 is not present. This generally corresponds to the embodiment of Figure 7, except for the omission of the cowl.
- the upper end of the support 7 is secured to the hull of the boat by any suitable means, and the lower end of the support is unsupported.
- the cowl 10 could be omitted from the embodiment of Figures 8(a) and 8(b), with the upper end of the support 7 being secured to the hull of the boat by any suitable means, and the lower end of the support being unsupported.
- Figure 15 illustrates an end view of a further embodiment of the invention. This generally corresponds to the embodiment of Figure 7, except that the lower end of the support 7 is not secured to the cowl 10.
- the embodiments of Figures 13, 14 and 15 can be combined with any of the arrangements of mdder plates and/or trimming plates described herein.
- Figures 16 and 17 show a further embodiment of the invention in which the cowl 10 is not present.
- a mdder plate 13 is provided on the boat 1.
- the mdder is mounted downstream of the propeller, within the recess 2.
- the mdder plate is mounted for rotation about the axis X-X shown in Figure 1.
- the mdder shaft 14 is mounted in a watertight bearing 15 provided in the bottom of the boat.
- the axis X-X is substantially vertical when the boat is in its normal orientation, for example in a calm sea.
- Figures 16 and 17 generally corresponds to the embodiment of Figures 1 and 2, except that the mdder plate 13 is provided and the cowl 10 is omitted. Since the cowl 10 is omitted, the lower ends of the support 7 and the mdder shaft 15 are unsupported.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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AU15767/00A AU1576700A (en) | 1998-12-04 | 1999-12-06 | A marine propulsion unit and a boat having a marine propulsion unit |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9826565A GB2344333A (en) | 1998-12-04 | 1998-12-04 | Marine propulsion unit |
GB9826565.5 | 1998-12-04 | ||
GB9826562.2 | 1998-12-04 | ||
GB9826563.0 | 1998-12-04 | ||
GB9826562A GB2344331B (en) | 1998-12-04 | 1998-12-04 | A marine propulsion unit and a boat having a marine propulsion unit |
GB9826563A GB2344332A (en) | 1998-12-04 | 1998-12-04 | Marine propulsion unit |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000034118A1 true WO2000034118A1 (en) | 2000-06-15 |
Family
ID=27269571
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1999/004091 WO2000034118A1 (en) | 1998-12-04 | 1999-12-06 | A marine propulsion unit and a boat having a marine propulsion unit |
Country Status (2)
Country | Link |
---|---|
AU (1) | AU1576700A (en) |
WO (1) | WO2000034118A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1182125A3 (en) * | 2000-08-23 | 2003-07-23 | FB DESIGN S.r.l. | Bottom assembly for surface propeller propulsion systems |
EP1495267A2 (en) * | 2002-04-18 | 2005-01-12 | Advanced Marine Concepts, LLC | Air induction system for marine vessel |
EP1508515A1 (en) * | 2003-08-19 | 2005-02-23 | Flensburger Schiffbau-Gesellschaft mbH & Co. KG | Ship with one or more propellers |
Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1401963A (en) * | 1918-11-07 | 1922-01-03 | Charles A Criqui | Power boat |
US2064463A (en) * | 1933-03-18 | 1936-12-15 | Crosley Radio Corp | Motor boat and driving unit therefor |
US2705469A (en) * | 1951-10-30 | 1955-04-05 | H C Stulcken Sohn | Propulsion arrangement for ships |
US3626894A (en) * | 1970-06-01 | 1971-12-14 | Penn Yan Boats Inc | Tunnel stern boat |
US3742895A (en) * | 1970-07-08 | 1973-07-03 | Yamaha Hatuskoki Kk | Propulsion device for boats |
US3793980A (en) * | 1971-12-30 | 1974-02-26 | Hydrodynamic Dev Corp | Marine propulsion system |
US3823684A (en) * | 1973-03-02 | 1974-07-16 | J Baggs | Boat drive |
US3937173A (en) * | 1973-10-23 | 1976-02-10 | Penn Yan Boats, Incorporated | Deep-V tunnel stern boat |
GB2008520A (en) * | 1977-11-28 | 1979-06-06 | Skf Nova Ab | Propellers shrouds |
GB2152459A (en) | 1983-12-05 | 1985-08-07 | Barrus E P Ltd | Safety shielding of marine propulsion units |
US4545771A (en) * | 1982-08-23 | 1985-10-08 | Sanshin Kogyo Kabushiki Kaisha | Propeller |
WO1987001350A1 (en) * | 1985-08-26 | 1987-03-12 | Small Mark S | Propeller tunnel baffle and method |
US4871334A (en) * | 1988-08-04 | 1989-10-03 | Brunswick Corporation | Marine propulsion device with improved exhaust discharge |
US4911665A (en) * | 1988-08-04 | 1990-03-27 | Brunswick Corporation | Gearcase exhaust relief for a marine propulsion system |
US5529520A (en) * | 1993-10-04 | 1996-06-25 | Sanshin Kogyo Kabushiki Kaisha | Propulsion system for marine vessel |
US5816869A (en) * | 1997-07-15 | 1998-10-06 | Brunswick Corporation | Propeller for varying the exhaust length |
-
1999
- 1999-12-06 WO PCT/GB1999/004091 patent/WO2000034118A1/en active Application Filing
- 1999-12-06 AU AU15767/00A patent/AU1576700A/en not_active Abandoned
Patent Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1401963A (en) * | 1918-11-07 | 1922-01-03 | Charles A Criqui | Power boat |
US2064463A (en) * | 1933-03-18 | 1936-12-15 | Crosley Radio Corp | Motor boat and driving unit therefor |
US2705469A (en) * | 1951-10-30 | 1955-04-05 | H C Stulcken Sohn | Propulsion arrangement for ships |
US3626894A (en) * | 1970-06-01 | 1971-12-14 | Penn Yan Boats Inc | Tunnel stern boat |
US3742895A (en) * | 1970-07-08 | 1973-07-03 | Yamaha Hatuskoki Kk | Propulsion device for boats |
US3793980A (en) * | 1971-12-30 | 1974-02-26 | Hydrodynamic Dev Corp | Marine propulsion system |
US3823684A (en) * | 1973-03-02 | 1974-07-16 | J Baggs | Boat drive |
US3937173A (en) * | 1973-10-23 | 1976-02-10 | Penn Yan Boats, Incorporated | Deep-V tunnel stern boat |
GB2008520A (en) * | 1977-11-28 | 1979-06-06 | Skf Nova Ab | Propellers shrouds |
US4545771A (en) * | 1982-08-23 | 1985-10-08 | Sanshin Kogyo Kabushiki Kaisha | Propeller |
GB2152459A (en) | 1983-12-05 | 1985-08-07 | Barrus E P Ltd | Safety shielding of marine propulsion units |
WO1987001350A1 (en) * | 1985-08-26 | 1987-03-12 | Small Mark S | Propeller tunnel baffle and method |
US4871334A (en) * | 1988-08-04 | 1989-10-03 | Brunswick Corporation | Marine propulsion device with improved exhaust discharge |
US4911665A (en) * | 1988-08-04 | 1990-03-27 | Brunswick Corporation | Gearcase exhaust relief for a marine propulsion system |
US5529520A (en) * | 1993-10-04 | 1996-06-25 | Sanshin Kogyo Kabushiki Kaisha | Propulsion system for marine vessel |
US5816869A (en) * | 1997-07-15 | 1998-10-06 | Brunswick Corporation | Propeller for varying the exhaust length |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1182125A3 (en) * | 2000-08-23 | 2003-07-23 | FB DESIGN S.r.l. | Bottom assembly for surface propeller propulsion systems |
EP1495267A2 (en) * | 2002-04-18 | 2005-01-12 | Advanced Marine Concepts, LLC | Air induction system for marine vessel |
EP1495267A4 (en) * | 2002-04-18 | 2011-03-16 | Advanced Marine Concepts Llc | Air induction system for marine vessel |
EP1508515A1 (en) * | 2003-08-19 | 2005-02-23 | Flensburger Schiffbau-Gesellschaft mbH & Co. KG | Ship with one or more propellers |
Also Published As
Publication number | Publication date |
---|---|
AU1576700A (en) | 2000-06-26 |
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