GB2322610A

GB2322610A - Hydrofoil Rowing Boat

Info

Publication number: GB2322610A
Application number: GB9704329A
Authority: GB
Inventors: Michael John Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-01
Filing date: 1997-03-01
Publication date: 1998-09-02
Also published as: EP0861771A3; GB9704329D0; EP0861771A2

Abstract

A rowing boat has a hull a, a seat c for an oarsman and an associated stretcher j, the seat and the stretcher j being relatively movable fore and aft as the oarsman rows, the hull a having a hydrofoil n associated therewith for raising the hull above the water as the boat is propelled by the oarsman, the arrangement being such that the position of the centre of gravity of the boat and oarsman remains generally constant relative to the hydrofoil. In the arrangement shown the seat is mounted on a substruture d which is vertically movable, with the hydrofoil being connected to the substructure by a linkage p,q,r,s,t such that as the hull rises out of the water the linkage lowers the substructure by the same distance as the hydrofoil raises the hull from a position in which the hull is floating in the water. Other arrangements of seat and hydrofoil are disclosed (see Figs 4-6).

Description

HYDROFOIL BOAT 2322610 This invention titled "HYDROFOIL BOAT" comprises

means of mounting a seat and hydrofoil on a rowing or sculling boat so that the centre of gravity of the rower or sculler and the boat remain in an approximately constant position relative to the hydrofoil during the actions or rowing or sculling and a variation of the invention provides that some or all of the means used by the rower or sculler for support and to drive the boat forward are adjusted in height above water level when the hydrofoils provide lift.

In this specification the word "boat" is used to encompass sculling boats and rowing boats the word "operator" is used to encompass a person or persons engaged in sculling or rowing the word "sculling" is used to encompass the actions of sculling (with two sculls) and rowing (with one oar) the words 'hydrofoil" and "hydrofoils" are used to encompass one hydrofoil or a plurality of hydrofoils which are provided and positioned to move through water, individually or together, to provide lift the word "hull" is used to describe the outer shell of a boat which displaces water when the boat is floating the word "seat" is used to describe the seat on which an operator sits the word "rigger" is used to describe a frame fixed to a boat which supports a gate which holds an oar or scull and which serves as the fulcrum for the oar or scull and in this description the word is used to encompass one rigger for a rower or two riggers for a sculler the word "stretcher" is used to describe the support for an operator's feet, which may include means to hold the feet in a chosen position the term "seatdeck" is used to describe the component of a boat which supports the seat the word "slide" is used to describe the means by which some components of a boat slide fore and aft relative to others during the actions of sculling the term llworkframell is used to describe components of a boat, notably the rigger and the stretcher, which are normally in fixed positions relative to one another to 1 enable an operator to apply power to drive the boat forward, the word "fore" describes a position towards the front of a boat or a movement towards the front the word "aft" describes a position towards the stern of a boat or a movement the stern other words and terms in this specification are applied in accordance with normal usage among those skilled in the arts of rowing and sculling.

The invention overcomes obstacles and limitations experienced in using hydrofoils on boats: if a hydrofoil is fixed to the hull of a conventional boat, the boat becomes unstable when the hydrofoil lifts because an operator carrying out the actions of sculling moves his or her body weight alternately fore and aft in the boat on a sliding seat, therefore moving weight fore and aft relative to the hydrofoil position. Moreover if a hydrofoil is fixed to the hull of a conventional boat, any lift from the hydrofoil raises the seat and workframe above the levels at which the operator can most efficiently carry out the actions of sculling.

The invention comprises a hydrofoil and a seat linked to a boat such that the centre of gravity of the boat and an operator on the seat remain in an approximately constant position relative to the hydrofoil during the actions of sculling, through the seat remaining in a constant position in relation to the hydrofoil but the workframe sliding in relation to the seat and the hull or through the hydrofoil sliding in the same directions as the seat.

A variation of the invention comprises a level control means which causes the hull to lift upwards but the seat and workframe to remain at an approximately constant height above water level when the hydrofoils move through water and provide lift. For example a level control means may comprise linkages between the hydrofoil and parts of the seat and workframe so that when the hydrofoil moves through water and generates lift, the linkages (i) cause the hull to lift up towards or above the surface of the water thus reducing drag or resistance to forward movement and (ii) at the same time cause the seat and workf rame to move down relative to the hull so that the seat and workframe remain at an approximately constant height above the water. When lift generated by the hydrofoil reduces, the function of the linkages is reversed, such that the hull moves downwards, for example driven. by a spring or pressure means, and the seat and workframe move upwards relative to the hull so that the seat and workframe remain at an approximately constant height above water level. The level control means thus enables the operator to drive the boat forwards while lift from the hydrofoil increases or decreases with minimum change in the movements of sculling.

Another variation of the invention provides for only part or parts of the seat and workframe, for example the rigger, to move down as lift from the hydrofoil increases and up as it decreases, 2 so that the movements of sculling can continue with minimum change.

Included within the scope of the invention are means as described above for one operator or for a plurality of operators in a boat.

The invention in now described by way of example only and referring to diagrams 1, 2, 3a, 3b, 3c and 4, which represent examples of embodiments of the invention. In order to provide a clear view of the essential components of the invention, the diagrams omit some components of boats which are non-essential to a description of the invention.

In the remainder of this specification, a letter in brackets following a reference to a feature of the invention indicates that the feature is shown in diagrams identified by that letter.

DIAGRAM 1: PLAN VIEW OF AN OPERATOR POSITION IN A BOAT Diagram 1 (scale approximately 1:20) shows a plan view of part of a boat including the position to be occupied by one operator and the means to be used by that operator in sculling.

The broken lines extending fore and aft show where the hull continues. This continuation may comprise one or more additional operator positions with the bow and stern of the boat beyond or, in the case of a boat with a single operator, the continuation comprises the bow and stern of the boat.

The outer surface of the hull is shown (a). The forward direction of movement of the boat produced by sculling is shown by an arrow (b).

The seat (c) is fixed on a seatdeck (d) which has one pin projecting at its f ore end (e) and one at the af t end (f The seatdeck is supported on the pins as described later.

Mounted on each side of the seatdeck is a bar (g) which slides fore and aft relative to the seatdeck. Fixed to the bars are riggers (h) and a stretcher (j). These components (g, h and j) make up a workframe.

The operator's feet on the stretcher are lower in the boat than the seat. Therefore an opening or well (k) is provided through the seatdeck so that the operator's feet and legs can project through the well to the stretcher.

There may be additional positions for operators fore and/or aft of the position shown in the diagram. Alternatively there may be spray covers (m) over the hull fore and aft of the seatdeck, to prevent waves or spray entering the hull.

DIAGRAM 2: SIDE VIEW OF AN OPERATOR POSITION IN A BOAT Diagram 2 (scale approximately 1:20) shows a longitudinal section 3 through part of a boat including the position to be occupied by one operator and the means to be used by that operator in sculling.

The further description of the diagram and the identification letters used for the various components are the same as provided for diagram 1.

DIAGRAN 3: TRANSVERSE SECTION THROUGH A BOAT Diagrams 3a, 3b and 3e (scale approximately 1:10) show a transverse section through a boat adjacent to the position to be occupied by one operator, showing a hydrofoil and a level control means.

Diagram 3a shows the hull floating, with no lift provided by the hydrofoil. Diagram 3b shows the boat with lift provided by the hydrofoil causing the hull to lift above the surface of the water and with point (t) which may link to the seatdeck and workframe as described below lowered relative to the hull, so that the seat and workframe remain at approximately the same height above water level. Diagram 3c is the same as 3b with a front view of the seat and workframe added.

In diagrams 3a, 3b and 3c, the outer surface of the hull is shown (a). The approximate water level is marked (v). A hydrofoil (n) is supported by two vertical rods (p) which connect at pivot points (q) to arms (r) which move on hinges (s) connected to the hull so that the ends of the arms at point (t) fall relative to the hull and press a spring or compression means (u) when lift on the hydrofoil increases and so that point (t) is raised relative to the hull by the spring or compression means when lift on the hydrofoil reduces. Since the distance between (s) and (t) changes as the arms (r) move, the arms may have elbow or sliding joints between (s) and (t). The components (p), (q), (r), (s) and (t) and variations of them for example as described below to support a hydrofoil are together called a hydrofoil frame.

An example of the invention may comprise a seatdeck and workframe as shown in diagrams 1 and 2 in which pins (e) and (f) are linked to point (t) of a hydrofoil frame or to a plurality of frames. The link may be direct for example if points (e) and (f) on a seatdeck are colocated with points (t) on hydrofoil frames. Alternatively the link may be as shown in Diagram 4 (scale approximately 1:20). In this example a hydrofoil frame with arms (r) is. attached to a rod (w) extending along each side of the boat and pivoted at points (x) equivalent to the points (s) referred to above. The rods (w) are rotated by movement of the arms (r). Arms (y) fixed between rods (w) and the pins (e) and (f) raise and lower the seatdeck as the rods (w) rotate in different directions.

Diagram 3c shows a hydrofoil frame with the rigger (h), the seat (c), the bars (g) and the pin (e), the last of these being colocated with point (t) of the hydrofoil frame. This diagram shows the rigger shaped to project over the side of the hull.

4 Reference is made below to variations, which individually or together lie within the scope of the invention:

The speed and extent of movements of the level control means may be regulated and adjustable so that when lift is generated by the hydrofoil, the hull rises and the seatdeck falls simultaneously rather than one after the other. it may also be adjustable so that the opposite movements occur simultaneously as lift generated by the hydrofoil decreases.

ii. A hydrofoil frame may comprise a plurality of arms, rods and linkages to provide the required strength and to serve additional functions. For example a hydrofoil may be supported under two pairs of arms (r), one pair forward of the other, to provide strength and so that the angle of attack of the hydrofoil can be changed by adjusting the relative lengths of the fore and aft rods (p) or equivalent links.

i. The position of the hydrofoil may be adjusted fore or aft by moving the arms (r) or the rods (w) fore or aft.

Some components may flex (the word "flex" being used to mean that the component changes shape under stress, with such change being reversed when the stress is reduced by elastic recovery of the former shape) at one or more positions as well as or instead of components moving on pivots or hinges. For example flexing or otherwise controlled movement of the points (s), pulled in by the arms (r) as the seatdeck moves down, may reduce the number of components required and may serve instead of a compression means (u) to lift the seatdeck up relative to the hull when lift generated by the hydrofoil reduces.

V. A boat may have one hydrofoil or a plurality of hydrofoils supported by one hydrofoil frame or a plurality of hydrofoil frames.

vi. Diagram 2 shows that the stretcher may be lower than the seatdeck and in this case part of the stretcher would be lower than the bottom of the hull when the seatdeck is lowered by the level control means. This may be accommodated by a depression in the hull below the stretcher (not shown in the diagram) which may also serve to keep the boat balanced on the hydrofoil by providing a point of flotation aft of the hydrofoil. Alternatively the stretcher may be located higher relative to the seat and rigger than in most conventional boats, this being acceptable because stability which may be lost by this may be recovered through stability provided by the hydrofoil and/or by the scope within the invention for the hull to be wider than a conventional hull.

vii. A boat may have a hydrofoil and/or fin and/or form suitable for planing on the surface of water fitted near the stern of the boat which rises towards or to the surface of the water when the boat moves forward and therefore lifts the stern of the boat so that the boat remains approximately level when the hydrofoil provides lift.

viii.In a boat in which the workframe is fixed relative to the hull and in which the operator slides relative to the hull, the centre of gravity of the boat and the operator may be maintained in approximately constant position relative to the hydrofoil by linking the hydrofoil to the sliding seat. The link may be direct, with an arm (aa) supporting the hydrofoil fixed to the seat. An example of this embodiment of the invention is shown in diagram 5 which is a side view of one operator position in a boat. Alternatively the hydrofoil may slide relative to the hull, for example being fixed to a slide means (called a hydrofoil slide (bb)) which may function like a conventional sliding seat and simultaneously the seat may slide relative to the hydrofoil (for example sliding on the hydrofoil slide) so that the hydrofoil slides fore and aft and the seat slides further fore and further aft. An example of this embodiment of the invention is shown in diagram 6 which is a side view of one operator position in a boat. In this example the sliding of the two slide means can be designed to provide that the centre of gravity of the operator and the boat combined remain in an approximately constant position relative to the hydrofoil during the actions of sculling. Either of these examples may be combined with a level control means as described above, which may be actuated by a separate hydrofoil, to adjust and control the level of the seatdeck, the hydrofoil support means, the rigger and the stretcher together or to adjust and control the level of one or more of these.

D97.RS 6 7

Claims

1 - 1. A rowing boat comprising a hull, a seat for an oarsman and an associated stretcher, the seat and the stretcher being relatively movable fore and aft as the oarsman rows, the hull having a hydrofoil associated therewith for raising the hull above the water as the boat is propelled by the oarsman, the arrangement being such that the position of the centre of gravity of the boat and oarsman is generally constant relative to the hydrofoil.

2. A rowing boat according to claim 1 wherein the seat and the hydrofoil are fixed relatively to the hull in a fore and aft direction and the associated stretcher is movable fore and aft as the oarsman rows.

3. A rowing boat according to claim 2 wherein the stretcher is connected to a rigger movable with the stretcher.

4. A rowing boat according to claim 2 or claim 3 wherein the seat and the stretcher are movable up and down relative to the hull in a vertical direction, means being provided for maintaining the seat and stretcher at a generally constant 8 height above water level as the hydrofoil raises the hull above the water.

5. A rowing boat according to claim 4 wherein the seat is mounted on a substructure that carries said stretcher, the substructure being movable in said vertical direction, the hydrofoil being connected to said substructure by a linkage such that, as the hull rises out of the water as the boat is propelled, the linkage lowers the substructure relative to the hull.

6. A rowing boat according to claim 5 wherein the linkage lowers the substructure by generally the same distance as the hydrofoil raises the hull from a position in which the hull is floating in water.

7. A rowing boat according to claim 6 wherein means are provided acting between the substructure and the hull tending to raise the substructure relative to the hull.

8. A rowing boat according to any one of claims 5 to 7 wherein the hydrofoil is connected to a pair of spaced vertical rods, each vertical rod being arranged on a 9 respective side of the hull, each vertical rod having an upper end pivotally connected to a first end of a respective arm mounted for pivotal movement intermediate the ends thereof, as the hull is raised or lowered, said pivotal movement causing said lowering and raising of the substructure.

9. A rowing boat according to claim 8 wherein each said arm has a second end, said second end being pivotally connected to the substructure and said pivotal mounting intermediate the ends thereof being a pivotal connection to the hull.

10. A rowing boat according to claim 9 wherein one of said pivotal connections is a sliding pivotal connection.

11. A rowing boat according to any one of claims 5 to 10 wherein said hydrofoil is one of two such hydrofoils, each hydrofoil being connected to the substructure by a respective linkage at respective spaced positions therealong.

12. A rowing boat according to claim 8 wherein each said arm has a second end connected to a rod intermediate the ends of the rod, the rod extending parallel to the length of the hull and lying within the hull adjacent a respective side of the substructure, the rods being rotatable to mount the arms pivotally and rods having respective ends connected to the substructure by links so that, as the hydrofoil raises the hull, the arms pivot the rods which, in turn, lower the substructure via the links.

is 13. A rowing boat according to claim 1 wherein the seat is movable fore and aft relatively to the hull and the associated stretcher is fixed relatively to the hull, the hydrofoil moving with the seat.

14. A rowing boat according to claim 13 wherein the seat is mounted on rollers and the hydrofoil is connected to the seat so that the seat and the hydrofoil slide together fore and aft as the oarsman rows.

is. A rowing boat according to claim 13 wherein the hydrofoil is connected to a substructure mounted on the hull for fore and aft movement relative to the hull, the seat being separately mounted on the hull for fore and aft movement relative to the hull, the seat being capable of greater fore and aft movement than the substructure.

11 16. A rowing boat according to any one of claims 13 to 15 wherein the seat is connected to the hydrofoil by a linkage such that as the hull rises out of the water as the boat is propelled, the linkage lowers the seat relative to the hull.

17. A rowing boat according to any one of claims 1 to 16 wherein at least one additional lift producing device is associated with the hull.

18. A rowing boat according to claim 17 wherein the hull has a bow, an additional lift producing device being provided at the bow.

19. A rowing boat according to claim 18 wherein said bow lift producing device is connected to means for changing the angle of attack of said lift producing device.

20. A rowing boat according to claim 18 wherein said bow lift producing device is such that the lift producing device provides lift that increases as the lift producing device is more deeply immersed.

12 21. A rowing boat according to any one of claims 17 to 20 wherein the hull has a stern, an additional lift producing device being provided at the stern.

22. A rowing boat substantially as hereinbefore described with reference to the accompanying drawings.