US3690284A

US3690284A - Rudder or keel for a wind and/or power propelled vessel

Info

Publication number: US3690284A
Application number: US134322A
Authority: US
Inventors: Ericus Gerhardus Van De Stadt
Original assignee: Stadt E G Scheepwert Nv Van De
Current assignee: Stadt E G Scheepwert Nv Van De; Van De Stadt Eg Scheepwert Nv
Priority date: 1971-04-15
Filing date: 1971-04-15
Publication date: 1972-09-12
Anticipated expiration: 1989-09-12

Abstract

A rudder or keel for a wind and/or power propelled vessel, the keel or rudder having at its rear part mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from or retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the keel or rudder. This will enhance the maneuverability and rudder movement, or increase the required keel lift by reducing leeway and/or improving the trim.

Description

[ 1 Sept. 12, 1972 [54] RUDDER OR KEEL FOR A WIND AND/OR POWER PROPELLED VESSEL [72] Inventor: Ericus Gerhardus Van de Stadt,

Beemster, Netherlands [73] Assignee: Van de Stadt, E.G. Scheepwert N.V.,

Zaandam, Netherlands 22 Filed: April 15,1971

21 Appl. No.: 134,322

52 us. 01 ..114/152 51 1111.01. ..B63l1'25/44 58 Field 61 Search ..114/162, 144, 145,152, 164, 114/167 [56] References Cited UNI'I'EDSTA'IESPATENTS 3,001,502 9/1961 Stoker ..114/167 Primary Examiner-Andrew H. Farrell Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A rudder or keel for a wind and/or power propelled vessel, the keel or rudder having at its rear part mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from or retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the keel or rudder. This will enhance the maneuverability and rudder movement, or increase the required keel lift by reducing leeway and/or improving the trim.

7 Claims, 3 Drawing Figures,

PATENTEBsEP 12 m2 sum 1 or 3 7 A TI l 7- 1 11 z i w 2 7 RUDDER R KEEL FOR A WIND AND/0R POWER PROPELLED VESSEL The invention relates to a rudder or keel for a wind and/or power propelled vessel.

It is known that under certain conditions such as for instance when manoeuvering in narrow fairways or in the case of sailing vessels requiring excessive weather helm when sailing large or before the wind the need may be temporarily felt for a, greater manoeuvrability or rudder moment than can be'obtained with the existing rudder. Similarly, circumstances may arise under which it is desirable, in order to reduce leeway and/or to improve the trim, to increase the transverse force or lift provided by the keel by increasing the area of the latter.

According to the invention the above. desiderata are met by the rudder or keel at its rear part having mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from and retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the rudder or keel. I

In a rudder or keel in the form of a hollow body with asymmetrically streamlined cross-section, according to a preferential embodiment of the invention, both sides of the hollow body have provided thereon an extension blade which which in its retracted position closely seats on the outer surface of the said body. Thus, extension of one of the said blades produces a asymmetrical wing section which, in accordance with the laws of hydrodynamics, upon movement ofthe body through the water in the direction of the chord creates a transverse component towards the side having the largest curved area, which component in the case of a sailing vessel can be utilized, by extending the leeward blade, to cause the incidental effect obtained by said wing section to exercise its influence in the desired direction.

' Further characteristics and advantages of the invention will become apparent from the following description of a preferential embodiment of a rudder constructed in accordance with the invention with reference to the drawings.

FIG. 1 shows a cross-section along the line 1-1 in FIG. 2 on a larger scale;

FIG. 2 shows a horizontal cross-section along the line II-H in FIG. 1 on a larger scale;

FIG. 3 shows a fragmentary section along the line III-III in FIG. 2 on a still larger scale.

The balanced rudder for a sailing vessel which has been chosen for purposes of illustration of the invention comprises a hollow body 1 which is streamlined in cross-section, its greatest thickness being forward of the middle. In the rearrnost portion of this streamlined rudder body, against both lateral faces thereof, a blade 2 which extends along its entire hight is mounted for longitudinal sliding movement. The inner side of these blades has a curvature which corresponds with that of the concerning lateral face of the rudder body 1 while the curvature of their outer side is slightly greater so that the blades 2 taper towards their front and rear end and therefore do not appreciably interfere with the smooth contour of the concerning lateral face of the rudder body irrespective of their position thereon.

In the chosen example the longitudinal dimension of the blades 2 slightly exceeds half the longitudinal dimension of the rudder body 1. Approximately at a distance from their leading edge which corresponds with a quarter of their longitudinal dimension each of the blades 2 carries at its inner side two vertically spaced brackets 3 which are both guided in a longitudinal slot 4 in the wall of the hollow rudder body 1, the

. location and length of the longitudinal slots 4 being such that the blades 2 in their foremost or retracted position have their trailing edge in alignment or flush with the trailing edge of the rudder body and in their rearmost or extended position project rearwardly of the rudder body 1 by approximately half their width.

At their end which lies inside the cavity of the rudder body the two brackets 3 of each rudder extension blade 2 each carry a pinion 5 which, for a purpose explained below, is secured to a vertical rotary shaft 6 common to both pinions 5 which is supported in both brackets. The pinions 5 each mesh with a toothed rack 7 secured to the inner side of the concerning wall adjacent the guiding'slot 4 and apart from maintaining the blades against the outer side of the rudderbody 1 throughout the ex tent of their displacement with regard thereto also serve to transmit a displacing force from one of the brackets 3 to the other bracket by means of the common rotary shaft 6 so that the blades cannot take up an oblique position and jam.

In the illustrated embodiment displacement of the blades 2 with regard to the rudder body 1 through the distance permitted by the guiding slots 4 occurs by means of a hydraulic control system. This system comprises for each blade 2 a hydraulic ram 8 of which the piston rod 9 acts on one of the brackets 3 of the concerning blade 2. As shown in the drawing both hydraulic rams 8 are disposed in the lower part of the hollow rudder body 1 for cooperation with the lower brackets 3 in order not to form an obstruction for the rudder stock which must have its greatest strength in its upper part. In order to make allowance for the circumstance that in view of the interior shape-of the hollow rudder body 1 the path of movement of the points of application of the piston rods 9 with the brackets 3 is inclined with regard to the longitudinal center plane of the hollow rudder body 1 the hydraulic rams 8 and the piston rods 9 are each hinged to the rudder body 1 and to the blade brackets 3 respectively about a vertical spindle.

The hydraulic lines l0, ll, 12 extend upwardly along the rudder stock 13 and through the helm port socket 14.

It will be understood that a hollow keel body for a sailing vessel can be arranged in a completely corresponding manner and that in view of the converging lateral faces of the rudder or keel body only one of the two blades 2 can be extended at a time.

In the case of a rudder the extension of the blades 2 will result in an increased steering capacity but in view of the asymmetrical wing section obtained thereby such increase of the steering capacity will be greatest to port and to starboard when using the starboard or port extension blade respectively. By for instance, in the case of excessive weather helm to starboard, extending the port side rudder extension blade 2 more or less according to the degree of weather helm to starboard the rudder deflection which is otherwise necessary to compensate for the weather helm but is detrimental to the speed of the vessel can be reduced to a smaller value.

Although in the case of a keel the end. in view is primarily a decrease of the drift and the drift angel rather than an increase of the steering capacity, similar considerations apply. By more or less extending the leeward keel extension blade the asymmetrical wing section of the keel body produced thereby will create a larger or smaller transverse pressure component in the leeward direction which will decrease the drift angle, whereby the vessel, for instance by sailing closer to the wind, will have to cover a shorter distance for reaching its objective which more than compensates for the decreased speed as a result of the increased coefficient friction.

I claim:

1. Rudder or keel for a wind and/or power propelled vessel, characterized in that the rudder or keel at its rear part has mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from and retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the rudder or keel.

2. Rudder or keel according to claim 1 in the form of a hollow body with asymmetrically streamlined crosssection, characterized in that both sides of the hollow body have provided thereon an extension blade which in its retracted position closely seats on the outer surface of the said body.

3. Rudder or keel according to claim 2, characterized in that each extension blade is secured to the hollow body by means of at least one bracket projecting into that body through a longitudinal slot in the wall thereof which bracket(s) or one of which brackets is or are acted on by operating means.

4. Rudder or keel according to claim 3, characterized in that each extension blade has two vertically spaced brackets which carry a pinion at their inner end, said pinions being secured to a common rotary shaft extending perpendicularly to said longitudinal slot and each ride on a toothed rack secured on the inner side of the concerning wall when the extension blade is extended and retracted.

5. Rudder or keel according to claim 4, characterized in that the control means each consist of a piston rod of a hydraulic ram secured inside the hollow body.

6. Rudder or keel according to claim 5, characterized in that the fore-end of each hydraulic ram and the rear-end of each piston rod hinges about a hinge pin extending parallel to the pinion shaft in the front of the cavity of the hollow body and on the concerning bracket respectively.

7. A wind and/or power propelled vessel fitted with a rudder and/or keel according to claim 1.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,690,284 Dated September 12 1972 Inventor) 1 Er icus Gerhardus Van De Stadt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet [73] "Van de. Stadt, E Gr Scheepwert N V." should read E. G. Van de Stadt Scheepwerf N. V..

Also on the cover sheet, insert [30] Foreign Application Priority Data April 16, 1970 Netherlands 7005497 Signed and sealed-this 20th day of March 1973.

(SEAL) Attest;

EDWARD MFLETCHERJR. ROBERT GOTTSCHALK Attestin Offi I Commissioner of Patents ORM DO-1050 H069) USCOMM-DC moan-ps9 U.$. GOVERNMENT PRINYING OFFICE. I969 0-365'J34.

Claims

2. Rudder or keel according to claim 1 in the form of a hollow body with a symmetrically streamlined cross-section, characterized in that both sides of the hollow body have provided thereon an extension blade which in its retracted position closely seats on the outer surface of the said body.