WO2007113306A1

WO2007113306A1 - Propulsion apparatus of retractable type for sailing boat

Info

Publication number: WO2007113306A1
Application number: PCT/EP2007/053265
Authority: WO
Inventors: Marino Quaiat; Karim Zorzin
Original assignee: Officina Navale Quaiat Srl
Priority date: 2006-04-04
Filing date: 2007-04-03
Publication date: 2007-10-11
Also published as: ITUD20060088A1

Abstract

A propulsion apparatus (10) of retractable type for a sailing boat (11 ) comprises a hydraulic motor (21 ) with a screw propeller (24) driven by means of a combustion engine (26) cooled by means of a cooling fluid, a containing compartment (31 ) inside the sailing boat (11 ) to accommodate completely, in recessed manner, the hydraulic motor (21 ), movement means (12) to move the hydraulic motor (21 ) in such a manner that it is selectively positionable in an extended position, outside the sailing boat (11 ), and in a retracted position, completely inserted in the containing compartment (31 ). The propulsion apparatus also comprises an emission pipe (13) to emit the exhaust gases of the engine (26) having the outlet end (35) completely inserted in the containing compartment (31 ), so as to emit the exhaust gases inside the containing compartment (31 ).

Description

"PROPULSION APPARATUS OF RETRACTABLE TYPE FOR SAILING

BOAT"

_{* * * * *}

FIELD OF THE INVENTION The present invention concerns a propulsion apparatus of the retractable type, particularly for a sailing boat, which does not have parts or appendixes immersed during sailing navigation. The sailing boat can be a competition sailing boat or a regatta boat, but also any "cruiser" boat.

BACKGROUND OF THE INVENTION It is known to make propulsion apparatuses with a screw propeller, of the retractable type, for sailing boats, driven by an internal combustion engine, usually Diesel. Such apparatuses can be selectively immersed under the bottom of the boat to achieve motorized navigation, whereas, during sailing navigation, they are completely retracted and inserted, recessed, inside a containing compartment of the hull, so as not to protrude from the latter and not to impede the sailing speed.

One disadvantage of such known propulsion apparatuses of the retractable type is that they are provided both with emission pipes, to emit the exhaust gases of the internal combustion engine and the secondary cooling fluid of the engine, usually sea water, and also with a pipe to take in such secondary cooling fluid. Such pipes normally protrude from the quickwork of the sailing boat, and thus embody external appendixes, protruding and immersed, which negatively affect the hydrodynamics of the boat during navigation, particularly during sailing. The disadvantages described above have a negative effect on the speed of the boats and are more marked in the field of competitive sailing boats, regatta boats or boats for match races or other, in which these unwanted, non-hydrodynamic appendixes considerably damage the competitors during the sailing race; often, in fact, a gain or loss of speed, albeit minimal, can make the difference between winning and losing such sailing competitions.

A purpose of the present invention is to achieve a propulsion apparatus of the retractable type for sailing boats, which does not have any immersed apparatus when the boat is sailing.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purpose, a propulsion apparatus for a sailing boat, for example of the competitive, or regatta, type, but applicable also to the so-called "cruiser" type, comprises a screw propeller connected to propulsor means, a containing compartment provided inside the hull of the sailing boat and able to completely accommodate, in recessed manner, at least said screw propeller. Moreover, movement means are able to vertically move at least said screw propeller from an extended position, outside the hull and under the waterline of the sailing boat, to a retracted position, completely inserted in the hull, inside said containing compartment, and vice versa.

According to a characteristic feature of the invention, said propulsor means comprises at least hydraulic motor connected to the screw propeller, to follow the vertical movement thereof, so that also the hydraulic motor in said extended position is outside said hull and under the waterline, while in said retracted position is completely inside said containing compartment. The hydraulic motor can be fed by water, oil, or any other suitable fluid. Moreover, the hydraulic motor is connected, through a hydraulic circuit, to pump means, which comprise a hydraulic pump connected to an internal combustion engine fixedly disposed inside the hull of the sailing boat. Moreover, an intake pipe is provided to intake cooling water for said combustion engine directly from the sea. More in particular, said intake pipe has at least an end part associated to the screw propeller to follow the vertical movement thereof, so that also said end part of the intake pipe is outside the hull and under the waterline to intake sea water, in said extended position, while in said retracted position is completely inside said containing compartment.

In addition, an emission pipe is provided to emit the exhaust gases of said combustion engine outside the hull. More in particular, said emission pipe has an outlet end inserted in said containing compartment above the waterline, so as to emit the exhaust gases inside said containing compartment. Said emission pipe is also able to discharge into said containing compartment the cooling water used by said combustion engine. In this manner, said containing compartment is able to deaden the acoustic emissions of said combustion engine.

Moreover, as regards said containing compartment, a first fixed plate is provided to close the upper side thereof, while a movable lower cover is associated to the screw propeller to close the lower side thereof, when the screw propeller is in the retracted position.

The above-mentioned movement means comprises at least one hydraulic piston mounted on said first fixed plate and connected to a second plate movable vertically with respect to the first fixed plate. In particular, the hydraulic motor is connected to said second plate to follow the vertical movement thereof.

Advantageously the hydraulic motor and the screw propeller connected thereto are disposed inside a pipe segment substantially aligned with the longitudinal direction of the sailing boat. More in particular, said pipe segment is connected to said second plate and said lower cover is connected to the pipe segment.

Advantageously, the propulsion apparatus according to the invention, in its retracted position, does not have any immersed part protruding from the sailing boat, and therefore it does not have any obstacle that can negatively compromise the hydrodynamics of the boat during sailing navigation.

Moreover, advantageously, a breather pipe is further provided to connect said containing compartment with an outside environment at atmospheric pressure. In this manner, the breather pipe allows to - A -

normalize the pressure in the containing compartment during motorized navigation, notwithstanding the emission of the exhaust gases. In fact, by doing this, the invention prevents, during motorized navigation with the propulsor in the extended position, the pressure generated by the exhaust gases emitted into the containing compartment, together with the effect of the gas intake caused by the rotation of the screw propeller, from causing cavitation effects to the blades of the screw propeller, which are detrimental to the screw propeller itself and hence to the speed of navigation. According to another advantageous feature of the invention, the lateral walls of the containing compartment are made of the same material as the hull of the boat, for example a polymeric material, like a thermosetting resin, which is easy to shape. In this way, the walls of the containing compartment and the hull are fixed and connected to each other in a continuous manner and in this way an effective watertight condition is achieved between the walls of the containing compartment and the hull, preventing the drawing of water. Moreover, in this way mechanical stresses, deriving from heat dilations in the interface regions between different materials, are avoided. Advantageously, therefore, it is possible to effect maintenance operations and/or controls inside the containing compartment, with the propulsor in the extended position, accessing from inside or from under the boat, even when the latter is in the water, without water infiltrating into the hull. According to another advantageous feature of the invention, the apparatus is applicable both to boats designed and still to be built, and also to already existing boats.

In fact, in an extremely easy way, in a first step the containing compartment is made of thermosetting resin, and afterwards it is installed in the boat, adapting it to the characteristics of the boat. Then, the screw propeller and its hydraulic motor are installed, the movement means for removing the same, and the connections with the driving pump. Advantageously, the propulsion apparatus thus made is extremely easy and economic to produce, since it essentially consists of elements that are easily found on the market and is made using processes well within the capabilities of an artisan or equipped workshop.

BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic representation of a sailing boat having a propulsion apparatus according to the present invention, in an extended position;

- fig. 2 is a schematic front view of the propulsion apparatus in fig. 1 in a retracted position;

- fig. 3 is a schematic front view of the propulsion apparatus in fig. 1 in an extended position;

- fig. 4 is a schematic lateral view of the propulsion apparatus in fig. 1 in an extended position. DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF

EMBODIMENT With reference to fig. 1 , a propulsion apparatus 10 according to the present invention is shown mounted on a sailing boat 11 having a hull 28 with a waterline 30 and having a longitudinal direction S.

The propulsion apparatus 10 (figs. 2, 3 and 4) comprises a hydraulic motor 21 and a screw propeller 24 connected thereto. The hydraulic motor 21 is driven, through a suitable hydraulic circuit, by a hydraulic pump 33 connected to a Diesel-type combustion engine 26.

The combustion engine 26 is of any known type and is normally cooled by means of a cooling circuit with cooling water, taken in directly during navigation, for example sea water. The propulsion apparatus 10 also comprises a containing compartment 31 , made inside the hull 28 of the sailing boat 11 , to accommodate completely both the hydraulic motor 21 and the related screw propeller 24, recessed, during sailing navigation. The containing compartment 31 is laterally delimited by lateral walls 34 made of fiberglass, advantageously like the hull 28, or of other materials such as carbon fiber with a vinylester matrix or epoxy resin.

Moreover, the propulsion apparatus 10 comprises hydraulic pistons 12, of the cylindrical type, and having shafts 36 driven by a hydraulic pump 29 (fig. 4), for example fed electrically, to move the hydraulic motor 21 with the screw propeller 24 along an axis Y, alternately upwards and downwards with respect to the boat 11 (figs. 2 and 3). In this way the hydraulic motor 21 is selectively positionable in an extended position (figs. 1 , 3 and 4), outside the hull 28 and below the waterline 30, and used during motorized navigation, and in a retracted position (fig. 2), completely inserted into the containing compartment 31 , and used during sailing navigation, so that the hydraulic motor 21 with the screw propeller 24 does not impede the sailing speed by reducing the hydro-dynamics of the boat.

Moreover, in the retracted position (fig. 2), the containing compartment 31 is closed at the lower part by a lower cover 25, connected and movable solidly with the hydraulic motor 21 and the screw propeller 24. The propulsion apparatus 10 also comprises a first fixed upper plate 17, advantageously made of stainless steel, which functions as a fixed upper closure of the containing compartment 31 , and a second movable lower plate 18 (figs. 3 and 4), also made of stainless steel. The hydraulic motor 21 is supported by the movable plate 18, which is operatively connected to the shafts 36 of two hydraulic pistons 12 mounted on the fixed upper plate 17 and controlled by a pump 29 (fig. 4).

The hydraulic pistons 12 are able to move, alternately and vertically, the movable plate 18 with respect to the fixed upper plate 17 and, in turn, the hydraulic motor 21 and the screw propeller 24, with respect to the hull 28 of the sailing boat 11. The movable plate 18 is guided by vertical fixed guides 19, preferably made of stainless steel and attached to the upper plate 17, so preventing oscillations of the hydraulic motor 21 during the upward and downward movement thereof. The hydraulic circuit that connects the hydraulic pump 33 to the hydraulic motor 21 comprises a tank 27, wherein a driven fluid is contained (water, oil, or any other suitable fluid), a first drive pipe 20, a second drive pipe 120 and a bleeder pipe 14. The three pipes 20, 120 and 14 are provided with end portions 220, 320 and 114, respectively, of the telescopic type (fig. 4) to follow the vertical movement of the hydraulic motor 21.

By inverting the direction of flow of the drive fluid in the first and second pipe 20, 120, it is possible to invert the direction of rotation of the hydraulic motor 21 and of the screw propeller 24 connected thereto, and hence the direction of navigation of the sailing boat 11.

The three pipes 20, 120 and 14 are connected to passage holes provided in the fixed plate 17, and packing means 16 are provided (figs. 2 and 3) to make the passage holes watertight. The cost of embodying the present invention is therefore comparable to the classic propulsion mechanisms, for example the straight line type or the S-drive type, but with the advantages connected to the possibility of inserting the hydraulic motor 21 in a recessed manner into the boat and the absence of protruding appendixes during sailing. The propulsion apparatus 10 also comprises an intake pipe 23, equipped with end parts 123, 223, which are constantly below the waterline 30 and which, in the retracted position (figs. 2 and 3), are completely inserted into said containing compartment 31 and in no way protrude from the sailing boat 11. The intake pipe 23, in particular by means of its end part 223, in the extended position (figs. 3 and 4), both during the motorized navigation and sailing navigation, is able to take in cooling water directly from the sea. The end part 223 is at least partly outside the hull 28 of the sailing boat 11 , protruding downwards, beyond the screw propeller 24, so as to have at least a portion immersed in the water during navigation and thus able to take in the necessary cooling water for the engine.

The intake pipe 23 is made of the telescopic type, so as to follow the alternate movement of the hydraulic motor 21 between the extended position and the retracted position (figs. 2, 3 and 4), and vice versa.

The propulsion apparatus 10 comprises also an emission pipe 13 to emit the exhaust gases produced by the combustion engine 26 when it works. The outlet end 35 of the emission pipe 13 is completely inserted into the containing compartment 31 , so as to emit the exhaust gases directly inside the containing compartment 31 , without protruding from the hull 28.

Advantageously, therefore, the containing compartment 31 also functions as a silencer for the combustion engine 26, also obtaining an advantageous deadening of the acoustic emissions of the combustion engine 26.

Moreover, the emission pipe 13 also discharges the used cooling water, directly into the containing compartment 31.

Advantageously, therefore, the propulsion apparatus 10 does not need a trap system, since the outlet level of the used cooling water is always above the waterline 30.

The propulsion apparatus 10 also comprises a sleeve 15, having an inlet end 32 positioned in the containing compartment 31 , which fluidically connects the containing compartment 31 with an outside environment at atmospheric pressure, in order to let off the pressure generated by the exhaust gases during motorized navigation.

The hydraulic motor 21 is disposed inside a pipe segment 22 or tunnel made of fiberglass, of the tubular type, substantially aligned with the longitudinal direction S of said sailing boat 11 , and able to increase the thrust performance of the hydraulic motor 21. The upper part of the pipe segment 22 is connected to the movable plate 18, whereas the lower part of the pipe segment 22 is connected to the lower cover 25, in such a manner that it is also alternately movable, solidly with the hydraulic motor 21. In this way, the pipe segment 22 defines the vertical position of the lower cover 25, without having to provide auxiliary connection means between the hydraulic motor 21 and the lower cover 25, which would negatively impede the flow generated by the screw propeller 24, thus obtaining a reduction in the overall bulk of the propulsion apparatus 10. It is clear that modifications and/or additions of parts may be made to the propulsion apparatus as described heretofore, without departing from the scope of the present invention. According to a variant of the invention, the propulsion apparatus can comprise both an electric motor and an internal combustion engine, for example where the electric motor is used when the drive torque required by the user is low, while the internal combustion engine takes over from the electric motor when higher torques are to be delivered, and at the same time also loads the batteries of the electric motor. Moreover, according to another characteristic of the present invention, the propulsion apparatus is also provided with a safety mechanism, which substantially functions as a motor lock, preventing the start of the hydraulic motor 21 when it is in the retracted position and which, advantageously, also signals the extended or retracted position. Said mechanism is, for example, made by means of pressure switches, which measure the variation in pressure in the drive circuit of the telescopic cylinders, in the extended or retracted position, or proximity sensors with electromagnetic induction, or a mechanical switch of the micro-switch type.

Claims

1. Propulsion apparatus of the retractable type, for a sailing boat (11) having a hull (28), comprising:

- propulsor means (21 , 26, 33); - a screw propeller (24) connected to said propulsor means (21 , 26, 33);

- a containing compartment (31 ) provided inside said hull (28) and able to completely accommodate, in recessed manner, at least said screw propeller (24);

- movement means (12) able to move at least said screw propeller (24) from an extended position, outside said hull (28) and under the waterline

(30), to a retracted position, completely inserted in said hull (28), inside said containing compartment (31), and vice versa; characterized in that said propulsor means comprises a hydraulic motor (21 ) connected to said screw propeller (24) to follow the movement thereof, so that said hydraulic motor (21 ), in said extended position, is outside said hull (28) and under said waterline (30) and, in said retracted position, is completely inside said containing compartment (31).

2. Propulsion apparatus as in claim 1 , characterized in that said hydraulic motor (21 ) is fed, through a hydraulic circuit (14, 20, 120), by pump means (33) connected to a combustion engine (26) fixedly disposed inside said hull (28).

3. Propulsion apparatus as in claim 2, wherein an intake pipe (23) is provided to intake cooling water for said combustion engine (26) directly from the sea, characterized in that said intake pipe (23) has at least an end part (223) associated to said screw propeller (24) to follow the movement thereof, so that at least said end part (223) in said extended position is outside said hull (28) and under said waterline (30) to intake sea water, while in said retracted position is completely inside said containing compartment (31).

4. Propulsion apparatus as in claim 2 or 3, wherein an emission pipe (13) is provided to emit the exhaust gases of said combustion engine (26) outside said hull (28), characterized in that said emission pipe (13) has an outlet end (35) inserted in said containing compartment (31 ) above said waterline (30), so as to emit said exhaust gases inside said containing compartment (31 ).

5. Propulsion apparatus as in claim 4, characterized in that said emission pipe (13) is also able to discharge into said containing compartment (31 ) the cooling water used by said combustion engine (26).

6. Propulsion apparatus as in any claim hereinbefore, characterized in that a breather pipe (15) is further provided to connect said containing compartment (31 ) with an outside environment at atmospheric pressure.

7. Propulsion apparatus as in any claim hereinbefore, characterized in that a first fixed plate (17) is provided to close the upper side of said containing compartment (31 ), in that a movable lower cover (25) is associated to said screw propeller (24) to close the lower side of said containing compartment (31 ), when said screw propeller (24) is in said retracted position.

8. Propulsion apparatus as in claim 7, characterized in that said movement means comprises at least one hydraulic piston (12) mounted on said first fixed plate (17) and connected to a second plate (18) movable vertically with respect to said first fixed plate (17), and in that said hydraulic motor (21 ) is connected to said second plate (18) to follow the vertical movement thereof.

9. Propulsion apparatus as in any claim hereinbefore, characterized in that said hydraulic motor (21 ) and said screw propeller (24) are disposed inside a pipe (22) substantially aligned with the longitudinal direction (S) of said sailing boat (11 ).

10. Propulsion apparatus as in claims 8 and 9, characterized in that said pipe (22) is connected to said second plate (18) and said lower cover (25) is connected to said pipe (22).

11. Propulsion apparatus as in any claim hereinbefore, characterized in that said containing compartment (31) is able to deaden the acoustic emissions of said combustion engine (26).

12. Sailing boat (1 1 ) comprising a propulsion apparatus as in any of the preceding claims.