US3611973A

US3611973A - Rudder assembly

Info

Publication number: US3611973A
Application number: US16849A
Authority: US
Inventors: Robert B Stuart
Original assignee: PENN YAN BOATS Inc
Current assignee: PENN YAN BOATS Inc
Priority date: 1970-03-05
Filing date: 1970-03-05
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12

Abstract

A rudder assembly for high-speed, planing hulls includes a spray plate extending aft of the stern at the waterline, a propeller forward of the spray plate, a fixed vane extending downward from the spray plate to the center of the propeller, and a pivotal rudder blade behind and below the vane and extending from the top to the bottom of the propeller.

Description

United States Patent [72] Inventor Robert B. Stuart [51 Int. Cl B63h 25/06 Penn Yan,N.Y. [50] Field of Search 1 14/162, [21] Appl. No. 16,849 57, 66.5 P, 148,665 R; 115/39 {22] Filed Mar. 5, 1970 [23] Division of Ser. No. 722,320, Apr. 18,1 References Cited abandoned, which is a continuation-in-part UNITED STATES PATENTS ofser- Flo-776,829,061 20,1968 1,844,303 2 1932 Wagner 114/162 PatentNo- 3,515,087 1,897,824 2 1933 Scholz 114/162 145] Patented Oct. 12, 1971 [73] Assignee Penn Yan Boats, incorporated Emmme' A"dTew Farrell Penn ya", y Attorney-Cumpston, Shaw & Stephens ABSTRACT: A rudder assembly for high-speed, planing hulls includes a spray plate extending aft of the stern at the water line, a propeller forward of the spray plate, a fixed vane extending downward from the spray plate to the center of the RUDDPR ASSEMBPY propeller, and a pivotal rudder blade behind and below the 29 Chums 22 Drawmg vane and extending from the top to the bottom of the [52] US. Cl "73:221.? Ali/ 162 propeller.

PATENTEUUCT 1 2m 3.611873 sum 1 0F 4 A T TORNE YS INVLNIUK ROBERT B. STUART PATENTEI] our 1 2|97| 3,611,973

SHEET 2 OF 4 mvm mm. ROBERT B. STUART ATT NE Y5 PATENTEUncnmsn 3.611.973

SHEET 3 OF 4 63 FIG. I4

INVENTOR.

ROBERT B4 STUART W W MM ATTORNEYS PATENTEU UCT12|97I 3611.973

sumunm INVENTOI'. ROBERT 8. ST T BY M ATTORNEYS RUDDER ASSEMBLY CROSS-REFERENCES This application is a divisional of my parent application Ser. No. 722,320 filed Apr. 18, 1968, now abandoned, and refiled as a continuation-in-part Ser. No. 776,829, filed Sept. 20, 1968, now Pat. No. 3,515,087 issued June 2, 1970, on PLAN- ING BOAT.

THE NEED FOR IMPROVEMENT Hull and rudder design for planing boats is a subject of controversy and disagreement. Countless designs, combinations, and arrangements have been attempted, and no solution has been optimum. v

One planing hull recently preferred for many advantages is a deep-V" defined and described below. It generally offers a smooth ride and good performing, planing, handling, and steering characteristics. However, it also has several important disadvantages. The draft of a deep-V hull at the center of the stern creates problems. An outboard motor or inboard-outboard drive can be used, but fitting a single inboard engine to a deep-V hull requires that the engine be too far forward for proper balance and support in a relatively narrow portion of the V so that the shaft angle to a relatively deeply submerged propeller under the keel line of the hull will not be too steep. Inboard-outboard arrangements cost more than a generally simpler inboard drive, and are also more expensive to maintain, more easily damaged, and cost more to insure.

These shortcomings of the deep-V hull have been known for some time, and the teachings of marine design authorities have not suggested workable solutions. The general object of this invention is to improve on the deep-V hull to preserve its desired qualities and overcome the drawbacks mentioned above.

Other objects of the invention include, without limitation:

a. a deep-V planing hull that is safer and provides an excellent ride, steering, performance, and handling;

b. a single inboard drive for a deep-V planing boat arranged to have a well-balanced engine position and a favorable shaft angle;

c. eliminating the expense of an inboard-outboard drive for a deep-V planning hull;

d. a deep-V planing hull with a shallow draft and a protected propeller;

e. a reaction drive for planing craft that allows full rpm. at any load;

f. general economy of construction and maintenance for a deep-V planing hull meeting the objects mentioned above.

These and other objects of the invention will be apparent hereinafter from the specification which describes the invention, its use, operation, and preferred embodiments, from the drawings which constitute a part of the disclosure, and from the subject matter claimed.

SUMMARY OF THE INVENTION By the invention: a deep-V planing hull is provided with a water tunnel formed below the operating waterline in the after region of the hull to open at the stern; a propeller is arranged for revolving inside the tunnel; a fixed vane is arranged behind the propeller to extend upward from the center of the propeller to the top of the tunnel; and a pivotal rudder blade is arranged on a stock mounted closely aft of the vane with the blade extending aft of the stock from the top of the tunnel to the bottom of the propeller and forward of the stock below the vane from the center of the propeller to the bottom of the propeller. The inventive tunneled hull can be used with other rudders, and the inventive rudder can be used with other planing craft.

THE DRAWINGS FIG. 1 is a side elevation of a preferred embodiment of the inventive planing boat;

FIG. 2 is a stern elevation of the boat of FIG. 1;

FIG. 3 is a bottom view of the after portion of the boat of FIG. 1;

FIG. 4 is an enlarged fragmentary stern elevation of the boat of FIG. 2;

FIG. 5 is a fragmentary cross section of the stern portion of the boat of FIG. 2 taken along the line 55 thereof;

FIG. 6 is a cross-sectional view of the vane and rudder for the boat of FIG. 5 taken along the line 6 6 thereof;

FIG. 7 is a stern elevation of a twin screw version of the inventive planing boat, 4

FIG. 8 is an elevational view of a preferred rudder blade for the inventive boat;

FIG. 9 is a cross section of the rudder blade of FIG. 8 taken along the line 99 thereof;

FIG. 10 is a cross section of the rudder blade of FIG. 8 taken along the line 10-10 thereof;

FIG. 11 is a central cross section of an alternative rudder blade for use in the inventive boat;

FIG. 12 is a bottom plan view of an alternative preferred tunnel shape for the inventive boat;

FIG. 13 is a partially cutaway, elevational view of the tunnel and rudder arrangement of FIG. 12;

FIG. 14 is a partially cutaway, elevational view of a stabilizer spray plate arrangement for the inventive boat;

FIG. 15 is a plan view ofthe spray plate of FIG. 14;

FIG. 16 is a plan view of an alternative preferred spray plate for the inventive boat; and

FIGS. 17-22 show fragmentary, partially schematic views of alternative preferred vane embodiments for the inventive rudder assembly.

DETAILED DESCRIPTION In the illustrated preferred embodiment of the invention, hull I0 is adeep-V planing hull as best shown in FIGS. 1 and 2. Hull 10 can have a variety of lengths, widths, shapes and sizes, and can include a variety of equipment within the spirit of the invention. Hull I0has a generally flat keel line 11 extending from a bow 12 to a stem 13, and throughout the specification and claims keel line" refers not only to the illustrated flat portion of keel line 11, but its extension aft toward and beyond stem 13.

A deep-V hull is generally characterized by a low keel line 11 with the bottom portions of the hull on each side of keel line 11 rising above the horizontal. For a hull to qualify as a deep-V" hull the angle of bottom portions 14 and IS on opposite sides of keel line 11 must be from 8 to 25 above the horizontal at the stem 13. The angle of hull bottom portions 14 and 15 generally increases toward bow 12. The resulting deep-V bottom knifes through the water to provide a smoother ride over waves and choppy surfaces than hulls with flat bottoms, round bottoms, or other configurations.

A planing hull is generally found in high-speed, pleasure boats. Hulls referred to within the spirit of the invention as planing hulls are those that the displacement lift from buoyancy is replaced by dynamic lift as speed increases, dynamic lift being the force produced by water at relative velocity impinging against the inclined bottom of the wall. Dynamic lift need not attain any particular percentage of the total life, but in faster and lighter hulls dynamic hulls are also characterized by relatively high speed propellers and relatively fast travel through the water, and although they are generally smaller craft, they can reach lengths of 50 feet or more.

Throughout the specification and claims deep-V planing hull refers to the above-described characteristics of deep-V planing hulls.

The after portion of the bottom of the center of hull I0 is provided with a water tunnel 16. Tunnel 16 is formed as a recess rising above keel line 11 beginning aft of the midships line of hull I0 and extending toward stern 13. The surface forming tunnel 16 is generally shaped in cross section as an inverted U that smoothly increases in size and diameter as extended aft to open fully at stem 13. Tunnel I6 is preferably made large enough to house propeller 17, and the top of tunnel 16 is below the operating waterline for hull 10.

Propeller 17 is mounted on shaft 18 leading from an inboard engine (not shown) arranged inside hull l0. Shaft 18 leads into tunnel 16 and is preferably in as nearly horizontal plane as possible. This produces the greatest possible horizontal vector for the thrust of propeller 17. Also, it permits optimum location of the engine for best balance in hull 10.

Propeller 17 is preferably arranged inside tunnel 6 and forward of stem 13 so as to operate above keel line 11. The blades of propeller 17 extend below the bottom of tunnel 16 as illustrated, but preferably not below the projected keel line 11. Also, propeller 17 is preferably fit closely within tunnel 16 by a small amount such as l inch or less.

The housing of propeller 17 within tunnel 16 reduces the chances of striking objects, and reduces the overall draft of hull l0. Tunnel 16 is preferably made no wider at its bottom than is necessary for housing propeller 17 so as not to reduce the flotation support for the stem end of hull and not to reduce the dynamic lift of the hull when in motion.

Rudder 20 is arranged aft of the center of tunnel 16 behind stem 13 and propeller 17. Rudder 20 includes a strut or vane 21, a stock 22, and a blade 23. A spray plate 24 and integral bracket 25 support rudder 20 at the stem 13 of hull 10, and bracket 25 includes

journals

26 and 27 supporting stock 22 for rotation.

Vane 21 is preferably formed integrally with plate 24 and extends below plate 24 to the center of propeller 17. The after edge of vane 21 is preferably faired to stock 22 as shown in FIG. 6 for minimum resistance and to prevent water flow between vane 21 and stock 22.

Stock 22 is turned by a conventional steering mechanism to adjust the position of blade 23. Blade 23 extends aft of stock 22 from the top of tunnel 16 to the bottom of propeller 17 and also extends forward of stock 22 below vane 21 from the center of propeller 17 to the bottom of propeller 17. The portion of blade 23 extending forward of stock 22 is preferably about 20 percent of the area of blade 23 for balancing rudder 20 and easing its steering. Also, the total area of vane 21 is preferably about 20 percent of the area of blade 23.

FIG. 7 shows a twin screw version of the inventive planing boat. Hull 30 is a deep-V planing hull with a low keel line 31.

Twin tunnels

32 and 33 are formed on opposite sides of keel line 31 for housing respective propellers 34 and as illus trated.

Tunnels

32 and 33 are below the operating waterline for hull 30, are preferably smoothly shaped for minimum resistance to water flow, and preferably substantially enclose

propellers

34 and 35.

Propellers

34 and 35 can be arranged to extend below the

tunnels

32 and 33, but preferably not below keel line 31.

Rudders

36 and 37 are arranged aft of each

tunnel

32 and 33 respectively, and

spray plates

38 and 39 are arranged over each respective rudder. Preferably rudders 36 and 37 have the same general construction of vane and blade as shown for rudder 20 previously described. The operating effect of the twin screw boat of FIG. 7 is substantially the same as the boat of FIGS. 1-6.

The inventive planing boat with the preferred hull, tunnel, and rudder combination has been built and tested and found to perform with surprising success. A full and accurate theoretical explanation of its operation is not known but as best understood, its operation will be described below. The invention is not limited to any particular theory of operation.

The high-speed stream of water through tunnel 16 is given a high rpm. spiral motion as it is directed aft by propeller 17. Fixed vane 21 as arranged at the top center of such stream tends to oppose the spiral motion of the slip stream and direct water straight aft from propeller 17. For normal right-hand propeller, the upper portion of the stream is spiraled to turn against the face of vane 21 that is illustrated in FIG. 5 and vane 21 directs the upper portion of the slip stream straight aft. The confinement of the water stream within tunnel 16 makes its upper portion particularly well defined so that vane 2| plays an important role in deflecting the spiral, stabilizing rudder 20, and preventing torque from the spiral stream from reflecting back through the steering mechanism. Vane 21, thus contributes to ease and accuracy of steering.

The lower portion of the spiral stream directed aft from propeller 17 is affected by the relatively still waterjust beyond the reach of blades 17 and is not so well defined as the upper portion of the slip stream. The portion of rudder blade 23 extending forward of stock 22 into the lower half of the slip stream thus operates in a less sharply defined portion of the slip stream for balancing rudder 20. The resulting steering effect of rudder 20 is practically equal between port and starboard turns, and the effort to lay the rudder on either side is approximately equal and relatively easy.

Spray plate 24 arranged over rudder 20 not only supports vane 21 but keeps down spray from rudder 20 and the wake of the boat.

Since the slip stream of water in the tunnel and aft of the propeller is fairly well defined by the tunnel, the resulting effect is a jetlike stream of water directed aft from the stern. This results in a reaction drive similar to a jet engine. One of the advantages of such a drive arrangement is that the engine and propeller r.p.m. do not decrease even under heavy load. As the load is increased in conventional planing craft, the propeller works against an effectively greater head and the increased-load reduces the engine rpm. for a power loss. This is particularly unfortunate since the fullest possible power is needed to handle the increased load.

With the reaction drive effect of the inventive tunnel and propeller arrangement, increasing or decreasing the load in the boat does not change the load on the propeller so that full power and full r.p.m. can be applied even with a heavily loaded boat. This insures that full driving power is available to propel heavy loads.

Rudder 20 can be made in a variety of sizes and shapes, and although the general arrangement of

vane

21 and 23 is preferred, these members can be formed in a variety of shapes. Spray plate 24 and bracket 25 can be omitted or can be formed in other shapes. The rudder stock, journals, or pintles can be varied and the fixed vane can serve as a strut supporting the blade. Furthermore, he preferred rudder 20 need not be used on the inventive tunneled hull and can be used with other planing hull and propeller arrangements.

FIGS. 8-10 show a preferred rudder blade 30 for use with the inventive boat. Blade 40 is especially shaped to provide more positive steering and excessive torque or bias feedback to the steering wheel. This is accomplished by slight bends in the trailing edge of rudder blade 40, as best shown in FIGS. 9 and 10.

Bend 41 of FIG. 9 turns the trailing edge of blade 40 slightly to port, and bend 42 of FIG. 10, turns the trailing edge of blade 40 slightly to starboard.

Bends

41 and 42 are somewhat exaggerated for illustration. The preferred bends are quite small and do not require very large areas of blade 40. For ex ample, bends on a 3-inch radius extending about I inch inward from the trailing edge of blade 40 ordinarily are ample.

Bends

42 and 41 are shown respectively in the upper and lower portions of blade 40 but their relative positions can be interchanged with the same result. The starboard bend 42, regardless of its vertical location, effects more positive steering to starboard, and the port bend 41 effects more positive steer ing to port.

FIG. 11 shows a cross section of an alternative rudder blade 43 taken along a horizontal midsection line to show a pair of trailing edge bends 44 and 45 that are adjacent to each other at the trailing edge of rudder blade 43.

Bends

44 and 45 function in the same way as bends 41 and 42 except they are positioned opposite each other rather than arranged vertically relative to each other.

FIGS. 12 and 13 show a flared tunnel arrangement allowing a stern extension of the inventive boat. Tunnel 47 housing propeller 48 in hull 46 is the same in shape and operation as previously described tunnels except for its stern end which is turned outward at both the port and starboard sides in

flares

49 and 50. This allows the stock 51 of rudder 52 to be placed inside the after end of tunnel 47 between

flares

49 and 50. The full port and starboard positions of rudder 52 are shown in broken lines, and flares 49 and 50 are made wide enough so that the distance 53 between rudder 52 and either flare 49 or 50 is substantially equal to the distance 54 between the rudder stock and the straight sidewall of tunnel 47. Then, with the rudder laid fully to either starboard or port, the jet stream of water aft from propeller 48 is not throttled off, but has its usual full passageway past rudder 52. Rudder 52 will not then obstruct the jet stream, but will direct it freely toward either side for positive steering.

The arrangement shown in FIGS. 12 and 13 allows stern 55 to be extended aft beyond the normal to overhang rudder 52. A downward and aft rake of stern 55 is shown in FIG. 13, but stem 55 could also be vertical or raked in the opposite direction if desired. Such a stern extension not only protects rudder 52 but gives a broader support surface at the after end of hull 46. This provides more dynamic lift when planing and a greater flotation support tending to keep the stern up and the bow down. Also, the flared tunnel and rudder arrangement illustrated in FIGS. 12 and 13 affords more positive steering when backing down, because rudder 52 operates in water that is somewhat restricted by tunnel 47 for a more forceful effect under sternway.

FIGS. 1416 show adjustable spray plates for trimming or stabilizing the inventive boat. Spray plate 56 is similar to previously described spray plate 24 in being arranged over rudder 57 at the after end of tunnel 58 in hull 59. Spray plate 56 then is approximately tangent to the top of the jet stream of water directed aft from propeller 60. A support bracket 61 fastened to the stern of hull 59 supports spray plate 56 and rudder 57, and a hinge 62 joins spray plate 56 to bracket 61 on a horizontal axis so that spray plate 56 is adjustable vertically over the top of the jet stream aft from tunnel 58. Hydraulic plunger 63 is connected between support bracket 61 and spray plate 56 for adjusting spray plate 56 vertically. The solid lines show an approximate upper position of spray plate 56. Hydraulic plunger 63 is connected between support bracket 61 and spray plate 56 for adjusting spray plate 56 vertically. The solid lines show an approximate upper position of spray plate 56. Hydraulic plunger 63 is preferably arranged to allow adjustment of spray plate 56 from controls located inside hull 59, but other adjustment means such as a multipositioned rod can be used to adjust spray plate 56 as desired.

The lowering of spray plate 56 into the jet stream of water past rudder 57 tends to the deflect such jet stream downward and to lift the stern end of hull 59. This can be done whenever hull 59 is loaded so as to carry its stern lower than desired. Spray plate 56 is more effective than conventional trim tabs since it operates on a relatively high-velocity jet stream of water giving a much greater dynamic lift per square inch of area than previously known trim tabs operating only at hull speed. Thus, the reaction drive, jet stream from tunnel 58 cooperates with adjustable spray plate 56 to make a small, simple, and very effective stabilizer of trim tab.

FIG. 16 shows a split spray plate forming a pair of spray

plate trim tabs

64 and 65 independently adjustable on hinge 62 by

hydraulic plungers

66 and 67 for port and starboard trimming of the inventive boat. The positioning of

tabs

64 and 65 is preferably controlled by the boat operator to adjust for changes in the horizontal trim of the boat. If one of the

tabs

64 or 65 is lowered relative to the other the lift at the stern of the boat will tend to be greater on the side of the lowermost tab to correct any uneven port and starboard loading of the boat. Again,

tabs

64 and 65 are relatively more efficient than previously known trim tabs because of their operation over the relatively high-velocity jet stream of water giving them enhanced dynamic lift. At the same time, both singleand double-spray plates operate to keep down the spray at the stern of the boat and make a smooth, even wake. FlGS. l719 show an alternative embodiment of the inventive rudder assembly with a horizontal vane 70 extending across tunnel 71 housing propeller 72. Spray plate 73 is arranged aft of tunnel 71, and rudder blade 74 is arranged below spray plate 73 and aft of vane 70. The alternative rudder blade 75 for horizontal vane 70 as shown in FIG. 20 is formed with a notch 76 to receive vane 70.

Vanes 77 are angularly spaced around tunnel 78 to extend radially inward relative to propeller 79 as shown in FIGS. 21 and 22. Spray plate 80 is arranged aft of tunnel 78, and rudder blade 81 is pivotal below spray plate 80 and aft of vanes 77 as illustrated. If desired, vanes 77 can meet in the region of the center of propeller 79, and different numbers of vanes can extend radially of the propeller within the spirit of the invention.

lt will thus be seen that the invention eliminates prior art disadvantages of deep-V hulls and preserves their best characteristics in a safe, good-riding, good-handling, planing boat. The invention also contributes to positive and effective steering, and trimming of the boat. Persons wishing to practicethe invention should remember that other embodiments and variations can be adapted to particular circumstances. Even though one point of view is necessarily chosen in describing and claiming the invention, this should not inhibit broader or related applications within the spirit of the invention. For example, the sizes, shapes and orientation of tunnels, rudders, propellers, vanes and spray plates can all be varied within the scope of the invention. Also, many changes can be made by those skilled in the art in adapting the invention to various boats and construction methods.

1 claim:

1. A rudder assembly comprising:

a. a spray plate arranged for extending aft of the stern of a planing hull approximately at the operating waterline of said hull;

b. a propeller arranged forward of said spray plate;

c. a vane extending downward from said spray plate to the region of the center of said propeller;

d. a rudder stock pivotally arranged closely aft of said vane;

and

e. a rudder blade arranged on said stock to extend aft of said stock from the region of said spray plate to the region of the bottom of said propeller and to extend forward of said stock below the region of the center of said propeller.

2. The rudder assembly of claim 1 wherein approximately 20 percent of said blade extends forward of said stock.

3. The rudder assembly of claim 1 wherein the area of said vane is approximately 20 percent of the area of said blade.

4. The rudder assembly of claim 1 wherein said spray plate includes a bracket extending upward from said spray plate and having means for pivotally supporting said rudder stock.

5. The rudder assembly of claim 1 wherein said stock is approximately vertical.

6. The rudder assembly of claim 5 wherein approximately 20 percent of said blade extends forward of said stock.

'7. The rudder assembly of claim 6 wherein the area of said vane is approximately 20 percent of the area of said blade.

8. The rudder assembly of claim 7 wherein said spray plate includes a bracket extending upward from said spray plate and having means for pivotally supporting said rudder stock.

9. The rudder assembly of claim 1 including means for hinging said spray plate to said hull and means for vertically adjusting the position of said spray plate.

10. The rudder assembly of claim 9 wherein said vertical adjusting means is hydraulic.

11. The rudder assembly of claim 9 wherein said spray plate comprises a pair of tabs adjacent each other along the fore and aft centerline of said hull and said vertical adjustment means is independent for each of said tabs.

12. The boat of claim 11 wherein each of said vertical adjusting means is hydraulic.

13. A rudder assembly for a tunnelled hull planing boat, said rudder assembly comprising;

a. a vertical extending from the region of the top of said tunnel to the region of the center of a propeller in said tunnel;

b. a rudder stock pivotally arranged closely aft of said vane;

and

c. a rudder blade arranged on said stock to extend aft of said stock from the region of the top of said tunnel to the region of the bottom of said propeller and to extend for ward of said stock below the region of the center of said propeller.

14. The rudder assembly of claim 13 wherein: a portion of the starboard face of said blade in the region of the trailing edge thereof being curved to starboard; and a portion of the port face of said blade in the region of said trailing edge being curved to port.

15. The rudder assembly of claim 14 wherein vertically separated portions of said trailing edge are curved respectively to starboard and to port.

16. The rudder assembly of claim 15 wherein approximately percent of said blade extends forward of said stock.

17. The rudder assembly of claim 16 wherein the area of said vane is approximately 20 percent of the area of said blade.

18. A rudder assembly for a planing hull having a relatively high speed propeller, said assembly comprising:

a. a spray plate arranged for extending aft of the stern of said hull approximately at the operating water line of said hull;

b. said propeller being arranged forward of said spray plate;

c. a fixed vane arranged aft of said propeller and extending generally radially of said propeller;

d. a rudder stock pivotally arranged aft of said vane and in the region of the forward end of said spray plate; and

e. a rudder blade arranged on said stock to extend aft of said stock below said spray plate and from the spray plate to the region of the bottom of said propeller and to extend forward of said stock in a region clear of said vane to balance said rudder.

19. The rudder assembly of claim 18 wherein approximately 20 percent of said blade extends forward of said stock.

20. The rudder assembly of claim 18 wherein said vane is vertical and faired to said stock.

21. The rudder assembly of claim 20 wherein said portion of said blade extending forward of said stock is arranged below said vane.

22. The rudder assembly of claim 18 wherein said hull is configured to form a tunnel around said propeller, and said vane extends radially inward from the wall of said tunnel.

23. The rudder assembly of claim 18 including a plurality of said vanes angularly spaced from each other.

24. The rudder assembly of claim 18 including means for hinging said spray plate to said hull and means for vertically adjusting the position of said spray plate,

25. The rudder assembly of claim 24 wherein said vertical adjusting means is hydraulic.

26. The rudder assembly of claim 24 wherein said spray plate comprises a pair of tabs adjacent each other along the fore and aft centerline of said hull and said vertical adjustment means is independent for each of said tabs.

27. The boat of claim 26 wherein each of said vertical adjusting means is hydraulic.

287 The rudder assembly of claim 1 wherein a portion of the starboard face of said blade in the region of the trailing edge thereof is curved to starboard, and a portion of the port face of said blade in the region ofsaid trailing edge is curved to port.

29. The rudder assembly of claim 28 wherein vertically separated portions of said trailing edge are curved respectively to starboard and to port.

UNKTED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,6.Ll,973 D d Ofitober l2 1971 Inventr s ROBERT B. STUART It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 6, line 73 of Claim 13,

the word -vaneshould be inserted after "vertical" Signed and sealed this 2nd day of January 1973..

SEAL) tteSt:

DWARD M.FLETCHER,JR. ROBERT GOTTSCHALK ttesting Officer Commissioner of Patents

Claims

1. A rudder assembly comprising: a. a spray plate arranged for extending aft of the stern of a planing hull approximately at the operating waterline of said hull; b. a propeller arranged forward of said spray plate; c. a vane extending downward from said spray plate to the region of the center of said propeller; d. a rudder stock pivotally arranged closely aft of said vane; and e. a rudder blade arranged on said stock to extend aft of said stock from the region of said spray plate to the region of the bottom of said propeller and to extend forward of said stock below the region of the center of said propeller.

5. The rudder assembly of claim 1 wherein said stock is approximately vertical.

7. The rudder assembly of claim 6 wherein the area of said vane is approximately 20 percent of the area of said blade.

13. A rudder assembly for a tunnelled hull planing boat, said rudder assembly comprising; a. a vertical extending from the region of the top of said tunnel to the region of the center of a propeller in said tunnel; b. a rudder stock pivotally arranged closely aft of said vane; and c. a rudder blade arranged on said stock to extend aft of said stock from the region of the top of said tunnel to the region of the bottom of said propeller and to extend forward of said stock below the region of the center of said propeller.

16. The rudder assembly of claim 15 wherein approximately 20 percent of said blade extends forward of said stock.

18. A rudder assembly for a planing hull having a relatively high speed propeller, said assembly comprising: a. a spray plate arranged for extending aft of the stern of said hull approximately at the operating water line of said hull; b. said propeller being arranged forward of said spray plate; c. a fixed vane arranged aft of said propeller and extending generally radially of said propeller; d. a rudder stock pivotally arranged aft of said vane and in the region of the forward end of said spray plate; and e. a rudder blade arranged on said stock to extend aft of said stock below said spray plate and from the spray plate to the region of the bottom of said propeller and to extend forward of said stock in a region clear of said vane to balance said rudder.

24. The rudder assembly of claim 18 including means for hinging said spray plate to said hull and means for vertically adjusting the position of said spray plate.

28. The rudder assembly of claim 1 wherein a portion of the starboard face of said blade in the region of the trailing edge thereof is curved to starboard, and a portion of the port face of said blade in the region of said trailing edge is curved to port.