Technical field marine propulsion, water vehicle propulsion, propulsion pod, jet propulsion

Technical problem

Technical problem to be solved by present invention is presence of Z or similar drives in retractable marine propulsion units resulting in possibility of mechanical failure and increased cost of maintenance.

A sailboat having an additional propulsion device can travel under sail or operating the propulsion device; a powerboat can travel only when operating the propulsion device; in both cases when not operating, the system is exposed to the marine environment.

When the propulsion device is not in operation the drive unit of a typical propulsion device offers water resistance and is exposed to fouling by waterborne organisms; additionally, in order to service the drive unit, it is necessary to haul the vessel.

State of the art

US3807347 describes a propeller and drive assembly for boats in particular as an auxiliary power source for sail boats including a drive assembly which is extendible through the hull below the water line of the sail boat into operating position then retractable to a position within the hull. The assembly includes a trunk preferably cylindrical in shape extending from the hull upward and closed by a plate member secured to the bottom of the drive assembly. A plurality of upstanding shafts align the drive assembly for substantially vertical movement. One of said shafts is operably connected to a power source for driving the propeller when the assembly is extended.

GB191024001 describes a pump (hereinafter Tesla pump) operated by fluid friction. An apparatus for imparting energy to or deriving energy from a fluid comprises a number of disks mounted on a rotary shaft . The required action is given by the friction between the disks and the fluid. When used as a pump, fluid is admitted by inlets, and discharged into a volute.

Description of new invention

Retractable marine propulsion system and method for its use solves above referenced technical problem by providing for electrically driven propulsion drive in either in form of a propeller, which is able of pitch and yaw, or in form of jet propulsion (in this case a Tesla pump but also any other applicable jet system) or a Tesla pump, ejecting water flow in direction opposed to the direction of desired water vehicle movement.

Water vehicles propulsion systems have several advantages and disadvantages. One of the main disadvantage is necessity for a propeller or pump to be constantly in water, resulting in increased drag during sailing, and in attachment of marine life prompting need for periodical cleaning and/or replacement .

For purposes of this specification, any pump supplying water jet in particular direction for propulsion can be used, however, use of Tesla pump seems to be of particular advantage .

It is therefore logical to use retractable propulsion systems such as one described in US3807347. The problem with such design is in need to transport momentum to the propeller resulting in very limited yaw, and non-existing pitch.

For maneuverability of water vehicle to increase it is advantageous to be able to turn the propulsion system in as many directions as possible. This specification describes retractable marine propulsion system capable of either expulsion and retraction only, or also turning around its axis for maneuvering and/or steering purposes, in addition to, or instead of a tiller or analogous steering means.

In order to describe possibility of direction change one needs first to define principal axes. First principal axis is one in direction of retraction of said marine propulsion system, in Fig. 1. Usually, this axis would be vertical if water vehicle is at rest, but it can be also at different angle to normal of the water surface plane. For the purpose of this application this axis is to be called retraction axis (1) . The second principal axis is the one in direction of water vehicle movement, in Fig. 2. For the purposes of this application this axis is to be called movement axis (2) . The third axis used in this application is direction of main propulsion direction. This is the direction of propulsion vector provided by propulsion of a propulsion member, this propulsion member being either a propeller, or a jet from a pump, preferably Tesla pump. For the purposes of this application this axis is to be called propulsion axis (3) .

If projections of propulsion axis (3) and movement axis (2) onto water surface plane are essentially co-linear (or if propulsion axis (3) and movement axis (2) are essentially co-linear) , the propulsion will propel said water vehicle in direction of movement axis (2) (assuming still water) . If projections of propulsion axis (3) and movement axis (2) onto water surface plane are not co-linear this will cause said water vehicle to move in direction which is not co- linear with movement axis (2) (assuming still water) .

It is advantageous to have non co-linear projections of propulsion axis (3) and movement axis (2) onto water surface plane if maneuverability of water vehicle is to be improved. In such a case water vehicle could move forward and lateral at the same time, or purely lateral, or lateral and reverse, depending on angle between projections of propulsion axis (3) and movement axis (2) . Such possibilities are depicted in Fig. 4 showing forward and lateral movement in (a), purely lateral in (b) and reverse and lateral in (c) , in all cases assuming still water (i.e. no water current) and showing propulsion vector (5) which is co-linear with propulsion axis (3) (not shown in Fig. 4) .

However, for such possibilities to exist, said propulsion member should be pivotable about retraction axis (1) . Extent to which said propulsion member is pivotable depends heavily on type of momentum transport from driving engine to said propulsion member.

State of the art uses driving engine separated from propulsion member, and momentum transfer to be achieved via shafts, pulleys, gears and similar mechanical momentum transport devices or manually.

It would be of great benefit if driving engine and propulsion member would reside in the same housing, and this is proposed by this invention. Further, such unit could be lowered into the water to be completely, or at least partially submerged. This would add additional benefit of reducing or even eliminating need for cooling water for said engine as said unit could easily be adapted to have sufficient surface area for cooling of said engine and/or propulsion member.

Retractable marine propulsion system comprises housing, said housing to be inserted into a hull of a water vehicle, said housing comprising retractable unit, said retractable unit further comprising at least one driving engine, and at least one propulsion member, said driving engine driving said propulsion member, said propulsion member creating propulsion for propelling of said water vehicle in desired direction; said retractable unit extendable from said housing to be predominantly inserted into water during said retractable marine propulsion system operation, and further said retractable unit retractable into said housing when said retractable marine propulsion system is not in operation . It would be of great benefit, to both reduction of C02 production and to reduction of noise pollution which is of particular importance in marine environment if such a driving engine would be an electric motor. During operation of said electric motor its noise would be reduced by submerging said unit at least partially into water. Of course, if said unit would be extended from a hull residing in water, such unit would be automatically fully submerged hence achieving both increased cooling and reduced noise.

Retractable marine propulsion system according to this invention wherein said driving engine is an electric motor or any other (i.e. hydraulic) .

Such electric driving engine would need a power source, either single power source, or several power sources. It would be of particular advantage if such power source would be incorporated into said retractable unit along with at least one driving engine and at least one propulsion member.

Retractable marine propulsion system according to this invention wherein said retractable unit further comprises at least one power source for powering said driving engine.

But even if such power source is not integrated within said retractable unit this invention would be of benefit. In such a case power source could be an on-board battery, or battery connected to a solar panel, or solar panel or plurality thereof, or a generator connected to ordinary internal combustion engine, or to turbine (including and not limited to steam turbine), and similar. Retractable marine propulsion system according to this invention wherein said power source is chosen from a group containing at least one battery, at least generator connected to internal combustion engine, at least one generator connected to turbine, at least one battery connected to at least one solar panel, or at least one solar panel, or combination thereof.

Said retractable unit driving engine is connected to at least one propulsion member for propelling of said water vehicle in desired direction. Such propulsion member could be ordinary fixed blade propeller but could also be a propeller with collapsible blades in order to allow for better retraction into said housing. Fixed blade propeller outer diameter would be limited to inner diameter (or lowest clearing if not circular in cross section) of said housing, and collapsible blade propeller with blades which could be bent or otherwise collapsed in accordance with state of the art would be better choice, or folding propeller in accordance with state of the art.

Such driving motor could also be connected to ordinary jet pump as found in any jet propulsion (ski), or Tesla pump as originally patented by Tesla, and developed in state of the art or any other pump or other propulsion system.

Retractable marine propulsion system according to this invention wherein said propulsion member is chosen from a group containing a fixed blade propeller, a collapsible blade propeller, a folding propeller, a Tesla pump, or any other pump or other propulsion system (a jet pump), or combination thereof . As described earlier, such retractable unit could be used for maneuvering if pivoted about retraction axis (1) . While shaft driven propellers with L or Z drives are limited in their pivoting because of mechanical limitation, retractable unit according to this invention could be pivoted for 360° or portion thereof using suitable controllers and position sensors which are available in state of the art. Such pivoting would usually be denoted as yaw.

Not only that. Said retractable unit could also be pivoted about lateral axis (which is essentially perpendicular to retraction axis) which means that the propulsion vector could be directed upward or downward. While this would be useful for semi-submergible water vehicles it could also be used for direction a water flow onto said hull or from said hull for cleaning or other reasons. Such pivoting would usually be denoted as pitch.

Retractable marine propulsion system according to this invention wherein said propulsion member is pivoted about an axis chosen from a group containing retraction axis (1), axis essentially perpendicular to retraction axis (1), or combination thereof.

This invention could be used for single hull, or multiple hull water vehicles, having said housing with retractable unit in at least one hull.

Retractable marine propulsion system according to this invention wherein said retractable marine propulsion system according to this invention is built into at least one hull of said water vehicle comprising at least one hull. It is also possible to mount two units in a single hull or multihull vessel and use both as steering with a combination of different thrusts to each.

This invention further describes a method for carrying out this invention.

Method for using a retractable marine propulsion system comprising the following steps:

extending a retractable unit from a housing of said retractable unit, said retractable unit comprising at least one engine and at least one propulsion member connected thereto ;

- pivoting of said retractable unit into desirable position;

- switching on said engine.

Method for using a retractable marine propulsion system according to this invention wherein said method further comprises the following steps:

- optionally switching off said engine;

- retracting said retractable unit into said housing of said retractable unit.

Further advantage of this system is also that said retractable marine propulsion system can be replaced easily for maintenance, as a whole, or one or more components of said retractable marine propulsion system. Said retractable unit can be removed while water vehicle is in water which is further advantage.

Method for repairing of said retractable marine propulsion system as described herein by replacing at least said retractable unit while water vehicle is in water, preferably during maintenance check but also possible during sailing if necessary .

Below, subject of this invention is further described by means of figures and preferred embodiment, said figures forming part of this description, and presenting:

Figure 1 shows at least one hull of water vehicle showing retraction axis (1) .

Figure 2 shows at least one hull of water vehicle showing movement axis (2), propulsion axis (3) .

Figure 3 shows cross section of water vehicle hull along movement axis showing retractable marine propulsion system shaft (4) for containing of retractable unit housing.

Figure 4 shows propulsion vector (5) for moving of said water vehicle (a) forward and lateral, (b) lateral, (c) reverse and lateral, this propulsion vector (5) co-linear with propulsion axis (3) .

Figure 5 shows operation of retracting of retractable unit showing retractable unit housing (6), retractable unit (7), propeller (8) being either fixed or foldable /foldable shown/, plunger (9), connecting rod (10), pivot (11), said operation as follows (a) retractable unit in operating position, (b) cross section of retractable unit in operating position, (c) start of pivoting of said retractable unit by means of plunger toward position for retracting, (d) position of retracting of retractable unit, (e) retracted position of retractable unit, Figure 7 shows retractable unit taken out from retractable unit housing (6) .

By applying reverse order of figure 5 the retractable unit is extended from (e) retracted position of retractable unit to (a) operating position of retractable unit.

Figure 6 shows operation of retracting of retractable unit, showing a pump, in this embodiment Tesla pump (12), retractable unit housing (13), combined retractable unit/plunger (14), said operation as follows (a) retractable unit in operating position, (b) cross section of retractable unit in operating position, (c) start of moving of said retractable unit toward retracted position, (d) retracted position of retractable unit, (e) retractable unit taken out from retractable unit housing.

By applying reverse order of figure 6 the retractable unit is extended from (d) retracted position of retractable unit to (a) operating position of retractable unit.

Figure 7 shows retractable unit taken out of retractable unit housing, shown in different views, from left to right: cross section of both retractable unit and retractable unit housing, cross section of retractable unit housing only, outside view of both retractable unit and retractable unit housing (no cross-sections) . It is self evident that such embodiment can be used for ease of maintenance, this being one of the advantages of this invention.

By applying reverse order of figure 5 the retractable unit is extended from (e) retracted position of retractable unit to (a) operating position of retractable unit. In preferred embodiment, retractable marine propulsion system of a water vehicle is comprised of housing (6) of retractable unit (7) positioned within a hull of said water vehicle, said retractable unit (7) comprising at least one engine and at least one propulsion member, in this case a folding propeller (8) as shown in Fig. 5. During sailing, said retractable unit (7) is housed within said housing (6) hence not presenting significant drag nor being in danger of touching a ground below a hull in shallow waters. When the operator decides to deploy said retractable unit (7), in this preferred embodiment the operator pushes a plunger (9) in direction of retraction axis (1), either by hand or by help of a motor, or by some other assistance. Said plunger (9) moves in direction of retraction axis (1) and pushes said retractable unit (7) by means of a connecting rod (10) . Said retractable unit (7) is eventually expelled from said housing (6) into water underneath said housing (6) . Once free of said housing (6) said plunger (9) by means of said connecting rod (10) pivots said retractable unit (7) about a pivot (11) until such time that said retractable unit (7) is in operating position (a) . This operation is seen in Figure 5, in following sequence - (e) , (d) , (c) , (b) . Then the engine is engaged, and retractable marine propulsion system used.

Figure shows folding of foldable propeller (8) . State of the art implies that folding propeller blades are spun out during operation (rotation) of said propeller, and otherwise they are folded. Hence, (a) , (b) , and (c) show propeller during operation, and (d) the propeller as stopped. Of course, this folding could also be controlled by other means such as actuators but this does not alter the essence of this invention .

Once need for said retractable marine propulsion system is exhausted, said retractable unit (7) is retracted into said housing (6) again by pulling of said plunger (9), again by hand or by assistance such as electric motor or similar.

In other preferred embodiment, use of pump, in particular Tesla pump (12) is shown, in analogous manner. In this case, retractable marine propulsion system of a water vehicle is comprised of housing (13) of combined retractable unit/plunger (14) positioned within a hull of said water vehicle, said combined retractable unit/plunger (14) comprising at least one engine and at least one propulsion member, in this case a pump (12), in this particular case a Tesla pump (12) as shown in Fig. 6. During sailing, said combined retractable unit/plunger (14) is housed within said housing (13) hence not presenting significant drag nor being in danger of touching a ground below a hull in shallow waters. When the operator decides to deploy said combined retractable unit/plunger (14), in this preferred embodiment the operator pushes said combined retractable unit/plunger (14) in direction of retraction axis (1), either by hand or by help of a motor, or by some other assistance. Said combined retractable unit/plunger (14) moves in direction of retraction axis (1) until said combined retractable unit/plunger (14) is eventually expelled from said housing

(13) into water underneath said housing (13) . Once free of said housing (13) said combined retractable unit/plunger

(14) moves until such time that said combined retractable unit/plunger (14) is in operating position (a) . This operation is seen in Figure 6, in following sequence - (d) , (c) , (b) . Then the engine is engaged, and retractable marine propulsion system used.

After operation, the reverse operation as shown in Figure 6 is used - sequence (b) , (c) , (d) by pulling combined retractable unit/plunger (14) inside of retractable unit housing ( 13 ) .

Obvious and additional advantage of Tesla pump is that it requires no additional sealing. The retractable unit is (more or less) snugly fitted within retractable unit housing (13) . Another advantage is that one can combine retractable unit with a plunger to form combined retractable unit/plunger (14) . Of course, both can still be separated (analogous to propeller solution) but such solution has obvious advantage in case of sealing, and also in case of maintenance forming a compact unit.