|HAO WALA NAMAN AT TAL OLI ILMIO RICHI DI MATTI
US009937992B2(12) Kuribayashi
United States
Patentet al.
(54 ) STEERING DEVICE AND METHOD FOR
STEERING THE SAME(71) Applicants:KAY SEVEN CO ., LTD ., Tokyo (JP );Noriyuki Sasaki, Kanagawa (JP );NATIONAL INSTITUTE OF

MARITIME, PORT AND AVIATIONTECHNOLOGY, Tokyo (JP );YAMANAKA SHIPBUILDING CO .,LTD ., Ehime ( JP ); KAMOME
PROPELLER CO ., LTD ., Kanagawa( JP )(72 ) Inventors: Sadatomo Kuribayashi, Tokyo ( JP );Noriyuki Sasaki, Kanagawa (JP )( 10) Patent No.: US 9,937,992 B2(45) Date of Patent:
Apr. 10 , 2018(51) Int. CI.

B63H 25 /38
B63H 5 / 15

CPC ........... B63H 25 /38 (2013 .01) ; B63H 25/ 382(2013 .01 ); B63H 25 / 383 ( 2013 .01); B63H

5/ 15 (2013 .01); B63H 2025 / 066 ( 2013.01)(58 ) Field of Classification Search

CPC ..... B63H 25 /38 ; B63H 25 / 382; B63H 25 /383
See application file for complete search history .
References Cited(56)

U .S . PATENT DOCUMENTS( * ) Notice:

Subject to any disclaimer, the term of thispatent is extended or adjusted under 35
U . S . C . 154 (b ) by 0 days .

(21) Appl. No.:

15 /115 ,601

(22) PCT Filed : Nov . 19 , 2014(86 ) PCT No.:
PCT/ JP2014 /080623$ 371 (c)(1),( 2 ) Date:

Oct. 13, 2016(87 ) PCT Pub . No.: W02015 /114916
PCT Pub . Date: Aug. 6 , 2015(65 )Prior Publication Data

US 2017 /0081010 A1

Mar . 23 , 2017

Foreign Application Priority Data
(30 )Jan . 31, 2014 ( JP ) ............................... 2014 -017401
Mar. 14 , 2014

( JP ) ............. ................. 2014 -052040

3/ 1942 Coolidge
12/ 1959 Parsons

2 ,276 ,163 A
2 ,916 ,005 A(Continued )Noriyuki Sasaki, Chigasaki -shi,
Kanagawa ( JP ) ; NATIONALINSTITUTE OF MARITIME , PORTTokyo (JP ); YAMANAKASHIPBUILDING CO ., LTD ., Imabari,
Ehime ( JP ) ; KAMOME PROPELLER
CO ., LTD ., Yokohama, Kanagawa (JP )( 2006 .01)

(52) U . S . CI.

(73 ) Assignees: KAY SEVEN CO ., LTD ., Tokyo ( JP );AND AVIATION TECHNOLOGY,(2006 .01)
( 2006 . 01)

B63H 25 /06

FOREIGN PATENT DOCUMENTS
FR
GB

1106851 A
2033324 A

12 / 1955

5 / 1980( Continued )OTHER PUBLICATIONS“ Regarding Evaluation of Support for Technology Development for

Curtailing CO2 from Marine Vessels” , accompanying material“ Regarding Evaluation of Support for Technology Development for

Curtailing CO2 from Marine Vessels” ,Ministry of Land , Infrastructure , Transport and Tourism , Marine Bureau, Heisei 25 Year Mar.

29, 2013 , 1 -6 pgs.

(Continued )Primary Examiner — Stephen P Avila(74 ) Attorney, Agent, or Firm — Muncy, Geissler, Olds &Lowe, P .C .

ABSTRACT(57 )A steering device having two rudder plates vertically sus
pended at a distance from an outer edge of a propeller. The

rudder plates are biaxially arranged and symmetrically rotate

around a screw shaft within a propeller radius from a screw

shaft center, on a propeller rotation plane , and are turned

from aside the propeller to downstream of the propeller byrotation of the steering shafts, each of which is driven
independently by two hydraulic driving mechanisms. The
steering action of the steering device has two modes: thetwo - independent mode, where the plates rotate in the same
direction , and the two -same direction modes , where the(Continued )US 9, 937, 992 B2
Page 2plates move in different directions. A method for steering thesame to enhance a thrust flow by increase in a propeller rateis also provided .
9 Claims, 26 Drawing Sheets

(56 )

JP
WO

3 ,872,817 A
4 , 895 ,093 A *5, 445 , 100 A * 8 / 1995 Finkl ..............

esse

50 -55094 A
56 -64900 U
01 -501384 A
H02 - 151595 A

5 / 1975

6 /1988

97 - 104 .
New Conception of New Steering Machine , Rudder System -Rotary

B63H 25 /48
114 / 163
B63H 25 / 38

Vane Steering Machine, Vec Twin Rudder System (1 ) Journal of theJapan Institute of Marine Engineering, vol. 45 , No. 2 , 2010 , pp .
93 - 99 .

“ Regarding Evaluation of Support for Technology Development for

Curtailing CO2 from Marine Vessels” , accompanying material“ Regarding Evaluation of Support for Technology Development for
Curtailing CO2 from Marine Vessels” ,Ministry of Land , Infrastructure, Transport and Tourism , Marine Bureau , Heisei 25 Year Mar.

5 / 1981

29, 2013, 2 pages.

6 / 1990* cited by examiner

5 /1989

1 /2010
4 /20114 / 2014

Vane Steering Machine, Vec Twin Rudder System (2 ) Journal of the

114 / 163

FOREIGN PATENT DOCUMENTS

WO 88 /03891 A1

4 / 1994

Japan Institute of Marine Engineering, vol. 45 , No. 3 , 2010 , pp .

8/ 1963 Schilling

3/ 1975 Duryea
1/ 1990 Dalsbo . .. . ....

06 - 92240
2010 - 13087 A
2011 - 73526 A
2014 - 73815 A

OTHER PUBLICATIONSNew Conception ofNew Steering Machine, Rudder System -Rotary

References Cited
U . S . PATENT DOCUMENTS
3 ,101,693 A

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US 9 ,937,992 B2
STEERING DEVICE AND METHOD FOR
STEERING THE SAME

steering shaft driving mechanism , and Patent Literature 3

proposes an oil hydraulic driving mechanism which enables
a rudder angle near 180 degree , using a rotary vane . Patent

CROSS -REFERENCE TO RELATEDAPPLICATION

Literature 4 describes the proposal that the effect of straights ening a propeller slipstream in a region sandwiched by two
rudders is exerted , and a high propulsive efficiency can be
The present application claims the priorities based on realized . However, in this latter arrangement, since theJapanese Patent Application No. 2014 -017401 “ STEERING rudders are arranged at the slipstream of a propeller, it seems
DEVICE” filed Jan . 31, 2014 and Japanese PatentApplica that there is a limitation in improvement of the propulsive
tion No. 2014 -052040 “ STEERING DEVICE ” filed Mar. 10 performance . Inter alia , in domestic vessels , since the sup
14 , 2014 , a content of which is incorporated herein by port by tugboats inside the bay will not be expected , thereference.
turning ability at the slow ship speeds should be maintained

TECHNICAL FIELD

by own ship handling . In the case of the rudder arranged

The present invention relates to a steering device which

navigation of these vehicles (see, for example, Non - Patent

propulsive efficiency, the special attention should be paid tothe movement of the rudder during the steering motion andalso mechanism and a steering method are the same. An
invention which recognizes or suggests a solution by dismechanism which improves the conventional rudder behinda propeller to enhance the propulsive performance of thepropeller . The mechanism also utilizes the rudder at the time

time of cruising concerning steering in this case has not beenfound out. In this respect, as a method for steering two
rudders, FIG . 4 of Patent Literature 5 presents a “method forallows for high propulsive performance of marine vehicles

due to saving of main engine fuel consumption duringoutside of the propeller slip stream aiming to only higher

Literature 1 ) . More particularly , the invention is a steering 20 criminating at the time of slow speed navigation and at theof stopping , enhances the steering ability at a slow vessel

displaying a moving direction for a system of two rudders ” .

speed , and reduces the underwater noise emitted by the 25 In this presentation the rudder position and a moving direc
propeller and the rudder. The present invention is suitabletion of a ship are displayed in ships having two rudders as

for effective water trafficking of ships by making use of such rudder arrangement of steering modes of (b ) indicatesrudder assisted steering of marine vehicles by using the forward right turning , and (e ) right turning on the spot.
method described in this application .
However the present invention is not suggested by a posi
30
tional relationship between a turning central position of two
BACKGROUND ART
rudders and a propeller in propeller slipstream arrangement.
In addition , there is proposed a ship in which two rudders are
The conventional rudder is positioned in the slipstream of arranged
on both sides of a propeller, for the purpose ofa propeller and hence by creating an additional resistant
the length of the propeller and that of a sterncomponent. When a rudder is not disposed behind a pro - 2535 shortening
shrudder for expansion
for a stein (Patent Literaturepeller but to remain in the same lateral plane with the 4 ). However, accordingoftospace
configuration
shown in FIG . 8 ofpropeller, it is left to arrange the rudder aside or in front of
the propeller. In view of interference with a propulsion shaft.
configuration of two or more rudders must be taken . On the

Patent Literature 4 , it seems that there is limitation in asteering range, and it is difficult to create a deflected stream

other hand, Non -Patent Literatures 2 and 3 pay an attention 40 of a propeller slipstream .
to the stopping ability , and propose the adoption of a
PRIOR ART LITERATURES
single-shaft propulsion with twin rudders for ship handling.
It is stated therein that, upon request of a sudden stop at

emergency, the two rudders cooperate at a right angle to a

Patent Literatureshull by taking position behind the propeller to block its 45

slipstream , and to provide the vessel with a powerful stop -ping ability . This way of steering and stopping technique is[Patent Literature 1 ] JP - A - 2014 - 73815[Patent Literature 2 ] JP - A - 50 - 55094

not much different from the prior art, in a point that the [ Patent Literature 3 ] JP - A - 2011- 73526
rudder still acts as a resistance component in the slip stream[ Patent Literature 4 ] JP - A - 2010 - 13087
of a propeller. As the prior invention of twin rudder, there is 50 [ Patent Literature 5 ] JP - B -6 - 92240
the invention disclosed in Patent Literature 1 . The same

invention prioritizes improvement in propulsive perfor
arranged in front of or aside the propeller, and does not[Non -Patent Literature 1 ]rotates around a steering shaft included in a rudder plate
face, the rudder plate cannot take position behind the pro

opmentfor Curtailing CO2 from Marine Vessels” , accom
pupanying material “ Regarding Evaluation of Support forpeller slipstream and hence a problem arises in the steering 60

Technology Development for Curtailing CO , frommance due to such a rudder plate that “ two rudder plates are

Non -Patent Literaturesconcentrate on the stopping ability. On the other hand, 55 https ://www .mlit. go . jp /report/ press /configuration having two steering shafts is also disclosed inkaiji06 _ hh _ 000061.html
FIG . 12 of Patent Literature 1 , and since a rudder plate“ Regarding Evaluation of Support for Technology Develability , particularly , at a slow vessel speed . This is problem
Marine Vessels” , Ministry of Land , Infrastructure , Trans
atic for domestic vessels and patrol boats which cannot
port and Tourism , Marine Bureau , Heisei 25 Year (2013 )receive assistance of tugboats. When the number of rudders
Mar. 29
is 2 , utilization of a camber comes in sight, but Patent [Non-Patent Literature 2 ] New Conception ofNew Steering
Literature 2 is limited to use the effect of camber in a twin 65 Machine Rudder System -Rotary Vane Steering Machine ,rudder arrangement in propeller slipstream . At a rudder
Vec Twin Rudder System (2 ) Journal of the Japan Instituteangle of 90 degree , it becomes necessary to also contrive aof Marine Engineering , vol. 45 , No . 3 , P97 - 104

US 9 ,937,992 B2[Non -Patent Literature 3 ] New Conception ofNew Steering

the steering shaft is biaxially arranged to rotate on both sides

Machine Rudder System -Rotary Vane Steering Machine ,Vec Twin Rudder System ( 1) Journal of the Japan Instituteof a screw shaft upper portion , each steering shaft connects
and suspends a rudder plate from the upper portion of therudder plate , and two rudder plates can turn from aside of aof Marine Engineering , vol. 45, No. 2, P93 - 99
5 propeller to a downstream of the propeller by rotating two
steering shafts .
SUMMARY OF THE INVENTION[ The Operational Advantage of the Invention ]In the invention , the steering shaft is biaxially arranged toProblems to be Solved by the Invention
rotate on both sides of a screw shaft upper portion , theAs shown above, many attempts have been made for a 10 steering shaft connects and suspends a rudder plate from thecontrivance to improve the propulsion performance of ships upper portion of the rudder plate , and a power mechanism
using the single -shaft and single rudder combination but such as an electric servomotor or a hydraulic cylinder turns

these attempts had limited impact on the propulsion perfor - two rudders from aside of a propeller to a downstream of themance under the restricted condition of the same configu - propeller by rotation of two steering shafts via a driving
ration . There is also contrivance for maintaining turning 15 mechanism . At the time of direct cruising , since two rudders
performance under configuration of twin -shaft propulsion ,are arranged on both sides of the propeller parallel with abut there is a problem in regards to the cost of additional
engine requirement. There is also contrivance for supple menting decrease in performance generated from shape

ship longitudinal axis, and do not hinder a propeller slip
stream , higher propulsive performance can be provided ascompared with the propeller arrangement of the convenment in cruising propulsion performance ofmainly travelingcan be used for each rudder as compared with the conven

pursuing high turning performance. The present invention is

the time of steering , since two steering shafts are used ,modification while maintaining turning performance by con - 20 tional technology . Since two rudders are arranged on bothtrivance of a rudder shape, but there is limitation in improve sides of the propeller, and the narrower and smaller rudder

straight. A Kort nozzle which eliminates the need for ational single rudder configuration , and the rudder receives adedicated rudder at a stern has a problem in a point of smaller fluid viscous resistance, and therefore , a high pro
propulsive efficiency performance . By simple arrangement 25 pulsive efficiency is obtained . It is preferable that the smallerof a rudder on both sides of a propeller, higher propulsive rudder herein has a length of about a half of that of the caseperformance than before is obtained , but it is insufficient for of single rudder configuration in terms of a rudder length . At

a new rudder and arrangement system offering a universal dedicated steering shafts are disposed for two rudder plates ,rudder of an era and propeller system for merchant ships 30 and two rudder plates are turned from aside of the propeller
which can provide a fast water stream utilizing a fossil fuelto the downstream of the propeller by the rotation of two

A new rudder is expected to save a fossil fuel consump -steering shafts . By this arrangement the turning radius cantion amount and a CO , generation amount due to improve -be smaller, two rudder plates and a rear end of the propeller

ment in propulsive performance , and maintain high turning

are brought close to each other, and a deflected propeller

performance and the stopping ability at emergency .
35 slipstream can be generated at a large rudder angle to realize
Then , at the time of straight cruising, it is preferable that a high turning performance . Herein , it is preferable that a
the rudder is not positioned in the propeller slipstream , andsmaller turning radius is , for example , such that the turningat the time of emergency stopping it is preferable that the radius is around a half of a propeller radius .
rudder is positioned in the propeller slipstream and can be
A power mechanism of the invention may be a hydraulicsteered until a right angle to a ship hull , and a turning 40 cylinder in which two steering shafts are rotated by amechanism realizing a rudder angle of 90 degree is prefer able .

Even when the rudder is not positioned in the slipstreamof a propeller, it is required to deflect the propeller slip
stream to maintain the turning ability .

cylinder shaft. This shaft is driven linearly by a hydrauliccylinder which is reciprocated by an oil pressure and crankmechanism which converts a reciprocating linear motion
into a rotation motion . Alternatively the power mechanism

45 may be a hydraulic cylinder constructed of a bevel gear

The present invention was done in view of the aforemen -which is attached to the steering shaft and can rotate thesteering device in which , in order to enhance a propulsion
efficiency of a propeller at the time of straight cruising, amechanism which converts a rotational plane from horizon
tal into vertical, Here , the power mechanism is an electrictioned problems, and an object thereof is to provide asteering shaft together with rotation , and a bevel gear

rudder is not positioned in the propeller slipstream . At the 50 servomotor or a hydraulic motor mechanism , or when thetime of emergency stopping , a rudder angle of 90 degree tothe ship hull enables the propeller slipstream to deflect toelectric servomotor mechanism or the hydraulic motor
mechanism is a vertical type , the steering shaft is directly

to maintain turning performance .

may be omitted .

problem ofmaintaining turning performance at a slow speed

rotation driven mechanism freely rotating the two steering

Means to Solve the Problems

direct cruising turn around the propeller with two steering
shafts being reciprocation - rotated by the cooperation of a

assist stopping and then back to straight position for turning

driven with the hydraulic motor, and the gear mechanism

For a new rudder, arrangement and movement of the 55 The power mechanism of the invention is a hydraulicrudder at the time of veering are further elaborated , acylinder and the driving mechanism thereof comprises ais recognized , and inconvenience of not disposing the rudder
shafts by a cylinder shaft and crank mechanism which areat the propeller slipstream is solved , and this is also areciprocation - driven by a hydraulic cylinder being recipro
steering device and a steering procedure of the present 60 cated preferably by oil pressure, and in this case , two rudderplates arranged on both sides of the propeller at the time ofinvention .

cylinder shaft and a crank mechanism . This mechanism is

The present invention solving this problem is as follows. 65 reciprocation -driven linearly with a hydraulic cylinder being
A steering device having a driving mechanism rotating areciprocated by an oil pressure , and a rudder angle seen fromsteering shaft, and a powermechanism driving this , wherein its ship axis is changed . By rotation of the steering shaft ofUS 9 ,937,992 B2
this driving mechanism , one of two rudders is moved into

direction , imparting the straightening effect at an inlet por

thepropeller slipstream , thereby, a more deflected slipstream
can be produced , and the effect of providing high turning

tion , at a propeller rotation surface in a region sandwichedby two rudders, water flow is bounded and regulated , andperformance is obtained , as compared with the case where
accelerating a flow rate of the slipstream , to enhance turning
the rudder plate is rotated around a shaft on a rudder plate 5 performance . In a case of modification of a fuller ship
on both sides of the propeller to obtain a rudder angle. Such aiming the larger cargo space , the flow regulation effect ofsimplicity is obtained that when a straight motion is con the present invention is increased because the upstream flow

verted into a rotational motion by a crank mechanism toof a propeller is not formed by enlargement of a stern shape.
rotate two steering shafts using a hydraulic device which is
In the present invention , it is preferable to characterize thenormally mounted in a ship as a power source , a steering 10 steering device according to claim 1 so that two rudderdevice mechanism may be on an extended line of theplates are arranged on both sides of the propeller at the aheadprevious mechanism , and the economical property is excel

condition of the ship , the length of two rudder plates areconjunction by a linking crank mechanism , since two rudder

are protruding ahead of the propeller plane in a bow direc

lent. In a configuration that two steering shafts are rotated inconfigured so as to locate the leading edges of two rudders

plates synchronously turn around the propeller, there is also 15 tion , and the action of straightening a propeller slip stream

an advantage that a steering control mechanism may be

simple .

is exhibited , and in this case, two rudder plates improve

propulsive efficiency by flow regulation effect on an outlet
flow of a propeller and turning performance by accelerating

The steering device , in which the power mechanism of theinvention is an electric servomotor or a hydraulic motor flow at the same time, when two rudder plates are arranged
mechanism , and the driving mechanism thereof is a bevel, 20 on both sides of the propeller at the ahead condition of thegear which is attached to the steering shaft and can rotate thesteering shaft together with rotation , and a bevel gearmmechanism
which converts a rotation planebetween verticalship , the length of two rudder plates are configured so as toof the propeller plane in a bow direction .

locate the leading edges of two rudders are protruding ahead

and horizontal is also preferable , and in this case , at the time
The steering device , wherein both of two rudder platesof straight cruising, when the electric servomotor mecha - 25 face each other across the propeller, and can turn simultanism or the hydraulic motormechanism is driven , a rudder n eously around the propeller in the same direction .
angle can be independently changed together with the steer

ing shaft which is rotation - driven with the bevel gear
Operational Advantage of the Invention
mechanism , to turn rudder plates arranged on both sides ofthe propeller around the propeller to move at least one 30 According to the steering device , both of two rudder
rudder plate of them to the downstream of the propeller, and plates face each other across the propeller , and turn simul

high turning performance is exerted . Further , when bothrudder plates are moved to a slipstream side around thepropeller until a plane vertically intersecting with a shiptaneously around the propeller in the same direction. Twothere is an advantage that ship handling becomes easy . When

propellers become simple such as the same motion , andlongitudinal axis , the complete stopping action can be pro - 35 a ship is faced in the right direction , the rudder on the rightvided . In this regard , since two rudders are independently
side is turned counterclockwise in front of the propeller, andsteering controlled by the electric servomotor mechanism or

the rudder on the left side is turned counterclockwise

the hydraulic motor mechanism , as compared with thesteering device described in the first part , soft control issimilarly behind the propeller, hence a deflected water
stream as an azimuthing thruster is generated , consequently

and the effect of providing the finer turning function is
obtained .
In the present invention , the steering device , in which two

simultaneously in the same rotation direction, and can turnpossible , a degree of freedom of ship handling is enhanced , 40 the advantage of excellentmaneuverability can be obtained .
The steering device, wherein two rudder plates can turnsimultaneously in a direction opposite to each other, whilerudder plates are arranged on both sides of the propeller atboth face each other across the propeller.
the ahead condition of the ship , the length of two rudder 45

plates are configured so as to locate the leading edges of the

Operational Advantage of the Invention

two rudders are protruding ahead of the propeller plane in abow direction , and the preferred action of straightening apropeller water stream is exhibited , and in this case, two

According to the steering device , two rudder plates canturn simultaneously in the same rotational direction , and canrudders provide the function of straightening a water stream 50 turn simultaneously in a direction opposite to each other,flowing into the propeller by interaction thereof to enhance

propulsive performance of the propeller. In a system ofsimply positioning the rudder forward away from the propeller in order to exclude a steering portion resistance force

while both face each other across the propeller. Each rudder

can rotate around its own steering shaft , independent fromeach other. In this case , like the invention described in thepresent claim , not only high turning performance such as a
generated from a propeller slip stream , such straightening 55 deflected water flow induced by a thruster, but also theaction is not obtained . The effect given by the rudder in maximum stopping ability can be provided , if both of themconnection with the present invention is different in prinface with the propeller at the same time, and rotate simul
ing
ciple from effect of the straightened stream generating
taneously around the propeller in the same direction , or iffunction by the rudder of propeller slipstream arrangement. both can constitute a plane intersecting vertically behind theAccording to the steering device in this case , two rudder 60 propeller at stopping motion . By a free rotating mechanism
plates are arranged on both sides of the propeller at the aheadaround the steering shaft, this stopping motion is realized . In
condition of the ship , and the length of two rudder plates areorder to make this stopping action work more effectively ,configured so as to locate the leading edges of two rudders

are protruding ahead of the propeller plane in a bow direc

smaller distances between two rudder plates and a rear endof the propeller are better. In the steering device , since thetion . In such configuration , there is the effect of suppressing 65 number of steering shafts is 2 , and a dedicated steering shaft
turbulence of a , water inflow into the propeller caused by aregion sandwiched by two rudder plates protruding in a bow

is disposed for two rudder plates , when the rudder plate isturned around the propeller, a turning radius can be reduced ,US 9 ,937,992 B2
distances between two rudder plates and a rear end of thepropeller are made to be close , and the effect of enhancing
the stopping ability is exerted .
The steering device , wherein a rudder angle range exceeds

shaft can be more reduced , a driving power mechanism may
be smaller, and the effect of realizing energy saving ofoperation is imparted , as compared with the case of vertical. An excessive gap between the propeller and the
70 degree , and two rudder plates cooperate to almost blockK 55 suspension
camberisreduced, and a thrust is maintained .
a propeller slipstream .
The steering device, wherein the rudder plate has a limitof a chord length which is allotted when one rudder plate isOperational Advantage of the Invention
arranged at a propeller slipstream , and a wing thickness ofplate is thinner than a wing thickness allotted
When a structure that rotation of an electric servomotor the rudder
one rudder plate is arranged at the propeller slip
mechanism or a hydraulic motor mechanism is directly when
stream .
transmitted to the rudder via a bevel gear or without via agear so as to freely rotate is adopted , a movable range isincreased , and it becomes possible to apply a large rudder
angle . By turning the rudder plate around the propeller , toapply a large rudder angle in a range of a total 180 degree 15

ormore of each rudder to turn to left and right 90 degree , it
becomes possible to utilize the rudder for stopping a ship ,Operational Advantage of the Invention
Two rudders are arranged on both sides of the propeller atththe time of direct traveling , and when one rudder of twinmance . According to the steering device , since two rudder

rudder configuration has a rudder area smaller than thatcompared with single rudder configuration , and a chordjust at the back thereof at emergency stop , the effect of

aspect ratio of a wing is increased to suppress a fluid

and it becomes possible to maintain high turning perfor -giving the same rudder performance by one rudder, as

plates move so as to almost block the propeller slipstream 20 length is smaller than that of the case of one rudder, anmaximizing a stopping force is exerted . An object of steeringin this case is to shorten a time when the propeller is freely
rotating with its own inertia after propeller driving is reset inresistance, and a high propulsive efficiency is obtained by a
The steering device , wherein the driving mechanism canthin small rudder .

the case necessitating emergency stop , and to impose the 25 perform by freely switching each mode of two -dependentmodes in which two rudder plates are turning - driven indereverse rotation of the propeller promptly .

The steering device, wherein the rudder plates are plate30
Operational Advantage of the Invention
Rudder plates are suspended from the steering shaft , andwhen rudder plates are integrally formed (monoblock ) by

pendently of each other, and a two -same direction mode in
direction .

which two rudder plates are both turning -driven in the same

like, and are molded into a reverse L - letter type.

Operational Advantage of the Invention
The invention is the steering device in which , when thewelding, press processing, forging processing or the like, adriving mechanism operates , driving is enabled by dividing
structure thereof becomes simple , and the advantageous 35 into two -dependent modes in which two rudders are driven
effect is imparted in a point of the strength and the eco - independently of each other so that a sufficient steering force

nomical property . Integral (monoblock ) molding of rudder can be generated even at a small vessel speed , and aplates into a reverse L -letter type is most simple configura
two- same direction mode mainly used at cruising in whichtion , and the most advantageous effect is imparted in a point two rudders are turned in the same direction . In the case
40 where a vessel speed is reduced , since a water current speedof the strength and economical property.
ne midder plates forma and a discharge flow rate produced by the propeller become
The steering device , wherein the rudder plates form acamber on a surface opposite to two rudder plates tosmall, and these become insufficient for steering, the present

generate an advancing thrust.

inventors came to realize that, in a region where a vessel

Operational Advantage of the Invention

speed is reduced , steering is different from that at cruising.

45 Then , according to the steering device of the present invention , in the steering device constituting the invention , a basic
framework compensating for decrease in a steering power atplate has a wing profile so as to generate a thrust for pushing a low speed and, at the same time, realizing improvement ina ship hull forward by the effect of a camber. By forming asteering performance and operating performance at cruisingcamber inside a flow between two rudder plates, a thrust 50 navigation is defined , as a steering category , for example , as
The steering device is characterized in that the rudder

pushing a ship hull forward can be generated . By enlarging

that with a predetermined vessel speed being a boundary , atcambers ( a distance between the mean line and chord line ofa vessel speed in a range smaller than the above vessela wing profile ), this thrust can be increased , but since a
resistance is increased simultaneously , there is an optimal

speed , the steering shaft can be steered in a two -independent
mode in which left and right rudders have no constriction

degree or less relative to a ship center line , the steering

speed , by dividing a steering mode into one mode oftwo -independent modes or a two - same direction mode,

camber. By increasing a front width of two rudder plates 55 independently of each other.
relative to a rear width , and tilting the rudder plates at 10
At the time of a low speed or at the time of a cruising
device is optimized .

The steering device, wherein the rudder plates are plate -improvement in operating performance of the present inven

like, and at least one of an upper portion or a lower portion 60 tion , the steering ability at a low vessel speed , silent naviof each of the rudder plates is canted towards a steering shaft
side.

Operational Advantage of the Invention

gation, and the emergency stopping ability at stoppage of aship are used depending on the situation , and the effectdepending on the situation is exerted .

The steering device , wherein in the two - independent
65 modes , the rudder plate on a broadside opposite to a veering

When a part is canted towards a steering shaft side, adirection can turn from aside of the propeller to behind themoment of inertia of the rudder plate around the steering

propeller by rotation of the steering shaft , and simultane

US 9,937 ,992 B2
10ously with this , or before or after this, the other rudder plate
on a broadside on a veering direction side can turn fromaside of the propeller to behind the propeller from a rudder

angle of 90° until a rudder angle takes a rudder angle of aninterference limit with other mechanism , by rotation of the 5steering shaft.

FIG . 2 A plane view of the steering device in connection
with the first embodiment at the time of steering .
FIG . 3 A front view of the same device .

FIG . 4 A perspective of the same device .
FIG . 5 A perspective of a gear driving mechanism of thesame device .

FIG . 6A A perspective of a crank driving mechanism inOperational Advantage of the Invention
connection with another embodiment of a driving mecha
device.
According to the present steering device , the effect insof 10 nismFIG of. 6Bthe Asame
perspective of a crank driving mechanism ingenerating a thrust flow to aside of a broadside in a veering
direction is obtained . It is preferable that steerage of the connection with another embodiment of a driving mecha

rudder plate on a broadside opposite to a veering direction
remains at a rudder angle of 45° to 55 ' , and other ruddernism of the same device .
FIG . 7 A plane view / a front view of the same device at theplate can turn at a rudder angle from more than 90° to a limit time of direct traveling.
that does not interfere with other mechanism such as the 15 FIG . 8 A plane view /a front view of the same device at thetime of starboard turning .
propeller and a screw shaft , for example, 105º .

A method for steering the steering device, comprising, in
FIG . 9 A plane view /a front view of the same device at thetime of larboard turning .
broadside opposite to a veering direction from aside of the
FIG . 10 A plane view /a front view of the same device atpropeller to behind of the propeller by rotation of the 20 the time of stopping .
FIG . 11 A comparison view between uniaxial turning ofsteering shaft,the two-independent mode , turning the rudder plate on asimultaneously with this , or before or after this , turning theother rudder plate on a broadside on a veering direction sidefrom aside of the propeller to behind of the propeller fromthe same device at the time of stopping .
FIG . 12 An arrangement view of a rudder plate and apropeller of the same device .

angle of an interference limit with other mechanism , byrotation of the steering shaft
and after turning of the two rudder plates, further increasingplate portion of a steering device in connection with asecond embodiment ( the case where a lower portion of areverse L -letter type rudder plate includes an arc shape).

a rudder angle of 90° until a rudder angle takes a rudder 25

FIG . 13 A front view including a propeller at a rudder
FIG . 14 A side view of the same device .

the propeller rotational speed more than the propeller rota

tional speed at the ship condition with a straight course 30

keeping.

FIG . 15 A perspective of the same device .

FIG . 16 A side schematic view of a stein of a ship using

a steering device in connection with a third embodiment.
FIG . 17 A front schematic view of a rudder and a steering

Operational Advantage of the Invention

shaft of the same device.

According to steering of the present invention , the effect 35 FIG . 18 A perspective schematic view of a rudder and aof increasing a flow velocity laterally will enhance the steering shaft of the same device .
steering ability . Particularly when it is desired to let the
FIG . 19 A horizontal sectional B -B schematic view of arudder work at a low vessel speed , according to the inven
driving mechanism of the same device .
tion described in the present claim , there is obtained the
FIG . 20 A plane schematic view / a front schematic view ofeffect of imparting the thruster function to the rudder without 40 the same device at the time of starboard turning in a
increasing a vessel speed , even when the more powerful two - same direction mode.
thruster function is exerted by the function of the propeller.
FIG . 21 A plane schematic view /a front schematic view of

Effect of the Invention
According to the present invention , at the time of straightcruising, the effect of imparting high propulsive perfor-

mance so that the rudder is not positioned at the propeller

slipstream is provided , and at the time of emergency stop -45

the same device at the time of larboard turning in a two
independent mode.

FIG . 22 A front view including a propeller of a rudderplate portion of a steering device in connection with a fourth

embodiment (case where a rudder plate includes a canted

portion ).

FIG . 23 A side schematic view of a stein of a ship using

ping, a high stopping force due to a rudder angle of 90 50 a steering device in connection with a fourth embodiment.
degree relative to a ship hull at the propeller slipstream is

FIG . 24 A perspective of the same device .

obtained , and the excellent effect of providing a steering

FIG . 25 A graphic view for comparing experimental,

device which freely deflects and straightens a water streamof the propeller for turning to maintain turning performanceis exerted .

According to the present invention , the further excellent

effect of providing a steering device which stillmaintains theresult of a steering force of each of a two -independent
modela two - same direction mode of a model steering device
55 in connection with one embodiment of the present invention .

MODE FOR CARRYING OUT THE INVENTION

turning ability due to generation of a thrust flow even at low

speed navigation using the present device and a method for

Each embodiment of the present steering device will besteering the same is exerted , and further, a steering device 60 illustrated below . FIG . 1 is a side view of a stern of a ship

which reduces a water cleaving noise of the rudder and amethod for steering the same are provided .

BRIEF DESCRIPTION OF THE DRAWINGS

equipped with a steering device according to a first embodi

ment (interior of a ship is a sectional view ), FIG . 2 is avertical view of the same steering device at the time ofsteering, FIG . 3 is a front view of the same steering device ,65 and FIG . 4 is a perspective of the same steering device .
steering device according to a first embodiment com
FIG . 1 A side view of a stern of a ship to which a first

embodiment of the present steering device is applied .

prises a propeller 20 attached to a rear end 11a of a stern tube

US 9 ,937,992 B2
12

11 of a ship hull 10 , two rudder plates 30 , and a mechanism

performance . FIG . 11 shows an possible position of a rudder

driving rudder plates 30 via a steering shaft 40 . Two rudderplate 230 which has turned around a steering shaft 240 at thecambered shape 31 is formed inside two rudder plates 30 .

shaft is uniaxial, and a possible turning arc 230 of the rudderplates 30 are arranged on both sides of the propeller 20 . A

time of emergency stopping in the case where the steering

The Front ends of two rudder plates extend forward of the 5 plate in this case is additionally shown in FIG . 20 . In the caseplane formed by a propeller rotation plane . The length of thisof two steering shafts , since the rudder plate turning radius

protrusion can be extended forward in such a way that it

becomes small by each turning , when two steering shafts

does not interfere with the ship hull 10 , the length depends

each have a turning mechanism , the rudder plate 230 can

on a wave created by a ship hull shape 10 and an economical

approach a position closer to the propeller as compared withvessel speed , and also depends on the straightening water 10 the case of a one steering shaft, a rudder angle can approachflow between the two rudder plates 30 , a use mode such asa forward thrust generated by the camber 31 of the rudder

vertically relative to a propeller screw shaft, and the braking
effect can be maximized .

plates 30 , and the water viscous resistance . It may be

F IG . 6A and FIG . GB show other version in which theand in this case aims at a low fluid resistance of the ruddermechanism of a hydraulic cylinder 100 and a crank mecha

optimized under these constraint conditions. The two rudder gear driving mechanism of FIG . 5 is a crank mechanism . As
plates 30 may be also rudder plates 30 having no camber 31 , 15 shown in FIG . 6A , by rotating the steering shaft 40 by aplates 30 and the straightening effect on vortex generation innism 110 , two rudder plates 30 can be freely turned . This isthe vicinity of a stein .
an embodiment in which oil pressure is a power source , andThe rudder plates 30 exhibit a reverse L -letter plate shape since an oil pressure system is frequently used in a ship it can
as shown in a front view 3 , and are fixed at the steering shaft 20 be utilized for this purpose so the driving device in connec
40 which is rotatably supported by the ship bottom portionof the ship hull 10 . At the time of steering ; with rotation oftion with the present invention can be realized at a smaller
cost.

propeller as shown in FIG . 2 . By turning of the rudder plates

crank mechanisms driving two steering shafts are connected ,the steering shaft 40 , the rudder plates 30 turn around theAccording to the steering device shown in FIG . 6B , the

30 around the propeller as shown in FIG . 2 rather than 25 and two steering shafts are rotated by conjunctive synchrorotation around a shaft on a plate surface . This increases thenization . A conjunctive synchronous rotation of two steeringformance is improved .

becomes easy , and a steering device mechanism may be also

deflected flow of the propeller slipstream , and turning per -shafts by crank mechanisms has an advantage that steering

The two rudder plates 30 have such a shape that a thrust simple . In the case of this embodiment, two rudder plates dofor impelling the ship hull 10 forward is generated by the 30 not cooperatively make a movement so as to almost block
effect of the camber 31. By tilting the rudder plates 30 at 10
the propeller slipstream , and increase in a stopping force indegree or less relative to a ship center line by making a front the case of sudden stop cannot be obtained , but by arranging
thickness greater than a rear thickness , the rudder plates are

two rudder plates on both sides of the propeller at the timearranged so as to have a suitable attack angle, they have anof direct traveling , two effects of capable of turning rudder

optimal rudder plate shape having little resistance on a flow 35 plates to the slipstream side of the propeller at the time ofin the vicinity of the stern of the ship hull 10 while rotation of a ship while obtaining high propulsive perfor
increasing a propeller efficiency , and an overall greater mance , and obtaining high turning performance can beachieved .
forward thrust can be obtained .
Upon rotation of the steering shaft 40 by the driving
FIG . 13 is a front view including a propeller of a ruddermechanism , shown in FIG . 1 and FIG . 5 , each driving shaft 40 plate portion of a steering device in connection with ais freely rotated using a bevel gear 120 and an electric
servomotor mechanism 130 . When the two rudders aresecond embodiment, FIG . 14 shows a side view of the same,and FIG . 15 shows a perspective of the same. The second

turned so as to be closed simultaneously from a direction

embodiment is different from the first embodiment in theseen from a ship stein 11 of FIG . 1 toward a center, they canfollowing points.
be positioned as shown in FIG . 2 and FIG . 10 , and can be 45 The second embodiment is the case where an arc shape isused as a brake at the time of an emergency . In addition , theelectric servomotor mechanism 130 exerts the same effect in
the case of a hydraulic servomotor mechanism , or a mecha -included at a lower portion of the reverse L - letter typerudder plate of the first embodiment, and provides the effectof realizing the effect imparted by the first embodiment by

nism of a combination of an electric servomotor and arequiring a smaller steering device driving mechanism . The

50 second embodiment will be illustrated below .
hydraulic servomotor.
FIG . 7 shows arrangement of the rudder plates 30 whenIn the second embodiment, a steering shaft 40 from which
travelling straight ahead , FIG . 8 shows the turning state of a rudder plate 30 is suspended , is arranged laterally from a

the rudder plates 30 at the time of right turning, FIG . 9 shows center of a propeller 20 at a distance D , and is fixed on a ship
the turning state of the rudder plates 30 at the time of left bottom 10 . Herein , D is a numerical value smaller than aturning , and FIG . 10 shows the turning state of the rudder 55 propeller radius R . An upper portion of the rudder plate 30

plates 30 at the time of stopping if the two shafts can be is constructed into a reverse L -letter type , and the rudder
driven independently by the driving mechanism as shown inplate 30 suspended from the ship bottom 10 is isolated from
FIG . 5 , turning positions from FIG . 7 to FIG . 10 become the steering shaft, center by R - D + a . a is a gap between apossible , it results in a steering device which affords a high propeller rotation radius and the rudder plate . A central
stopping force by imparting a rudder angle of 90 degree 60 portion of the rudder plate 30 , that is, a portion lower thanrelative to the ship hull 10 by the propeller slipstream at thea horizontal line passing through a propeller center shaft istime of emergency stopping , while providing the effect that a 1/4 arc , and is configured to be slightly isolated from , andthe rudder plates 30 are positioned on both sides of the opposite to the rudder plate which is similarly suspended
propeller to impart a high propulsive efficiency withoutfrom an opposite steering shaft. Herein , parameters of R , D
positioning in the propeller slipstream when straight cruis- 65 and a are optimally designed in view of various elements
ing, and freely deflects and straightens a water stream of thesuch as propeller performance, rudder performance, a shippropeller 20 in order to turn a ship , and assures good turning

type and the like .

US 9 ,937,992 B2
13
In order to turn the reverse L - letter type rudder plate 30

14from aside of the propeller 20 to a slipstream side of thearound the steering shaft 40 with a horizontal portion of apropeller 20 by rotation of two steering shafts 40, the rudder

L - letter type being an arm , the rotational inertia moment

plate surface is turned at a radius r from aside of thepropeller to be downstream of the propeller by rotation of

becomes great in proportion to a length of an arm to beturned , as compared with the case where the portion is 5 the steering shaft, the rudder is placed on both sides of therotated around the steering shaft in a form of inclusion of the propeller, two rudders each have the steering shaft, thesteering shaft in a rudder plate surface in the conventional
shaft, a larger shaft than before becomes necessary, andsteering shaft is attached off-center inside the rudder plate ,and each steering shaft rotates independently . This configu
rationdefines that a rudder face of the rudder plate forms a
disadvantage arises in respect of a combination with a ship 10 face isolated
from the steering shaft , and a rotation axis bytype, and an economic efficiency, in some cases. Even in the steering shaft
is not present in line with the rudder face ,such a case, if it becomes possible to reduce the inertia and makes the meaningof turning clear and, at the same
moment as much as possible so that a smaller steering device time,
definesthattherudderplate is positioned laterally
driving power source may be used , a more preferable
steering device excellent in energy saving and an operational 15 isolated at a distance a from the propeller rotation surface
efficiency can be provided . Herein , since the inertia moment outer edge . The steering shaft has a more compact configu
I of a mass point in at a distance r from a rotation center ration that it is arranged on an inner side than a propeller
radius, and makes clear a difference between rudder platesatisfies:
arrangement of the conventional steering device of two
1= mp2equation (1), 20 rudders (see FIG . 2 of Patent Literature 1 ). That is , this is aconcerning a portion lower than a horizontal axis line of a preferable embodiment in a point that a turning radius ispropeller central line of a reverse L -letter type rudder plate reduced , a turning moment of the rudder plate can besteering device . Then , as a power device driving the steering

portion of the steering device in connection with the first reduced in proportion to the square of a turning radius r, andembodiment shown in FIG . 3 , when a part of the rudder plate it becomes possible to miniaturize a driving mechanism andis a 1/4 arc shape as in FIG . 13 showing this embodiment, the 25 a power mechanism , and consequently , this leads to energy
distance from the steering shaft rotation center is reducedsaving which is an object of the present invention .
and , therefore , the inertia moment is reduced in proportion
In this way, concerning definition between parameters ,even when a turning radius r is more reduced , if a chord
to the square thereof.
Since a necessary driving force is in proportion to thelength of one rudder plate is a sufficient length for covering

inertia moment, and a driving energy is also in proportion to 30 a propeller radius R , it is preferable that the turning radius
ris around a half of the propeller radius R , a size of one
the second embodiment shown in FIG . 13 , it results in that rudder plate is defined from a relationship with a turninga smaller power mechanism is enough, and energy saving is radius of the rudder plate in view of a chord length of therealized . Energy saving is one object of the present inven
rudder plate covering the propeller radius R , and as a result,
35 harmonization with reduction in the turning moment of thetion , and this satisfies the aims of the invention .
In the second embodiment, a camber 31 is formed on a propeller is obtained , being preferable .
The size of two rudder plates which are arranged on both
surface opposite to two rudder plates , that is, inside therudder plates (FIG . 15 ). The camber aims at improving sides of the propeller is such that one rudder plate of twin
propulsive performance by a thrust generated by the wing rudder configuration can be reduced compared to the rudder
shape . Although the camber 31 is also formed in the first 40 area which imparts the same performance of a single rudder.

the inertia moment, in the steering device in accordance withembodiment, in the rudder plate of the steering device in
When a height of the rudder is the same, that is , conceptu
accordance with the second embodiment, by making aally , a rudder width in a vessel axis direction , a chord length
rudder plate lower portion of a reverse L -letter type a 1/4 arc in the case of a wing can be smaller than that of single
shape , the rudder plate becomes closer to the propeller, and rudder, and in this case , an aspect ratio of a wing becomes
since a water flow velocity in the vicinity of the camber is 45 greater. Since the wing having a greater aspect ratio supincreased , the secondary effect that a thrust becomes greater, presses reduction in a lift force and increase in a fluid

as it would with a fixed nozzle and an improvement in resistance due to wraparound from a wing end , a small
rudder satisfies a required specification , a width of the
propulsive performance is greater can be expected .
Then , a third embodiment of the steering device will be rudder is reduced , a rudder face which merely undergoes aillustrated . FIG . 16 is a side view of a stern of a ship 50 small fluid viscous resistance is formed , and a high propul
equipped with the steering device in accordance with the sive efficiency is obtained at the time of cruising, as com
third embodiment (the interior of a ship is shown by asectional view ), FIG . 17 is a front view of the same steering
device , and FIG . 18 is a schematic view of a perspective ofa rudder portion of the same steering device .
Also in the third embodiment, likewise the first embodi
ment, the steering shafts 40 are each arranged at a distancepared with single rudder which imparts the same rudder
performance .
Upon rotation of a steering shaft 40 by a driving / power
55 mechanism 90 , the steering shaft 40 is directly rotated by arotary vane -type hydraulic motor 140 (see FIG . 18 ). This
results in that two rudder plates 30 freely turn around theD smaller than a radius R of a propeller 20 from a screw
propeller 20 . That is, as shown in a sectional view of ashaft center 5 , a rudder plate surface of the rudder plate 30
driving mechanism shown in FIG . 19 , when a hydraulic oil
facing the propeller 20 is vertically arranged at a positive 60 is supplied into hydraulic chambers 132 , 133 which areminimum distance a from an outer edge of the propeller 20
partitioned with a vane 134 of a vane- type hydraulic motor

having a radius R on a rotation plane of the propeller 20 , andthe rudder plate surface is characterized in that a turning

radius is defined by a distance in which a radius r isrepresented by the following equation :p = R - D + a (> 0 ;R >Da > 0 )equation (1)140 by a power mechanism , the differential force works on

the vane 134 due to a pressure difference between left andright hydraulic chambers 132 , 133 partitioned by the vane,
65 and a rotor 130 is differentially operated . It results in that thesteering shaft 40 directly connected to the rotor 130 freely

turns the rudder plate 30 connected to the steering shaft 40 .

US 9 ,937,992 B2
15
In hydraulic chambers 132, 133 , a part of a semi-cylindricalspace is partitioned with the vane 134 , and since the vane16
direction is turned from aside of the propeller 20 to adownstream of the propeller by rotation of the steering
shafts 42 at a first stage, and at the same time, the otherrudder plate 32 on a starboard side is turned from aside ofpartitioning this can be rotated in a range of approximately

180° , a range exceeding 90°, for example , a wide rudder
5 the propeller 20 to the downstream of the propeller byangle range can be supported .
According to the third embodiment as stated above , therotation of the steering shaft 41, the rudder plate is turning

power mechanism of the driving mechanism is a vane -typedriven so as to take a rudder angle of 90° , and jointly as a

hydraulic motor mechanism 140, this is directly bound to thenext stage, the propeller rotational speed is increased thancenter from a direction seen from a stern 11 of FIG . 16 soregion , the rotation number of the propeller is suppressed

as to be closed simultaneously, two rudders can be also
emergency -braked at the time of emergency as in FIG . 10 ,rudder plates can be positioned at a slipstream atmore than

low in normal steering , and when a propeller water stream
generated , a sufficient turning power is not obtained . Then ,steering shaft 40 as a dedicated mechanism for each steering that at the time of straight travelling.
shaft 40, and when rudder plates 30 are turned towards a 10 Even in the two- independent mode , at a low ship speed

is at a low speed , since only a weak deflected flow is

90° up to maximally 105°, and a breaking power can be 15 in the case of starboard veering ship handling generating amaximized . In addition , the driving mechanism 90 may bethrust flow in the two -independentmode, the rudder plate 33

any mechanism as far as it is a separate power mechanism

on a port side opposite to a veering direction is turned , forand driving mechanism 90 which can independently drive

example , by 45° from aside of the propeller to the down

two steering shafts 40 freely , and may directly drive thestream of the propeller by rotation of the rudder shaft 42 at

steering shafts 40 using an electric servomotor mechanism 20 a first stage and , at the same time or as a second stage , when

as a power source , or may drive the steering shafts 40 via athe other rudder plate 32 on a starboard side is turned fromspeed reduction mechanism , and if necessary , vertical/hori-aside of the propeller to the downstream of the propeller by

zontal plane conversion of a rotating plane may be per-formed depending on arrangement configuration of each
instrument.

When the driving mechanism 90 is driven , it is preferable

rotation of the rudder shaft 41 to take a large rudder angleof 90° to 105°, a flow is concentrated from a port to a

25 propeller central side by the rudder plate 33 which hasturned by 45°, a pressure at a central portion becomes high ,that the steering shaft can be steered by switching into aton the other hand, a propeller water stream which is disleast two steering modes of a two - independent mode and a
two - same direction mode. Hereinafter, according to a steer

charged backward from a starboard right semicircle regionis blocked , by the rudder plate 32 taking a rudder angle ofing mode, motion of the rudder plate in the third embodi- 30 90°, a flow must be toward a lateral, but is pushed by ament will be illustrated using schematic views of a planepressure near a central portion of the propeller 20, and a flowview /a front view of FIG . 7 , FIG . 8, FIG . 20 and FIG . 21.

to a lateral of a starboard in a veering direction ( right) is

property of the steering mode are as follows.

possible by discharge of a lateral flow to the just beside a

A mechanism and a steering method appropriate to steering

generated. Then , ship handling similar to a thruster becomes

At the time of veering steering in the two-same direction 35 veering direction . At the time of porting the helm , left andmode, basically, rudders are symmetrically steered aroundright are inverted .

the propeller, and in the case where a ship is faced in the

Meanwhile , since almost all of a propeller water stream

right direction , when the rudder on a right side is moved

flows laterally, even when the propeller rotational speed iscounterclockwise in front of the propeller, and the rudder on

increased , a forward vessel speed is notmuch increased. On

counter current ( flow FR shown with two -dot chain line FIG .
20 ), and the effect of obtaining the desired steering property

the transverse direction is dramatically enhanced . That is,when veering steering in a two - independent mode is pera left side is turned , similarly counterclockwise at behind of 40 the other hand , when the propeller rotational speed isthe propeller , a rightward deflected slipstream (flow F shown
increased, since a water stream flowing laterally becomeswith two -dot chain line of FIG . 20 ) is generated from afast, and a flow rate is also increased , a ship control force inis exerted .

45 formed , as a third stage , the effect of dramatically enhancing

In the two-independent mode, left and right rudders are

independently steered . Steering in this independent mode isdetermined by a person , for example , a chief navigator, or amaster of a ship . For example , since when a ship speed isthe steering ability by increasing the rotation number of thepropeller 20 is obtained . In this case, even when the propeller rotational speed is increased , a speed of a ship is notincreased, and the rudder works as a thruster.

reduced , a current speed and a discharge flow rate generated 50

At the time of veering in the two -same direction mode, theby the propeller are reduced , and become insufficient forsteering, the rudder is steered in the two- independent mode

rudder plate on a side opposite to a veering direction isturned from aside of the propeller to the downstream of thebeing a steering mode corresponding to ship handling at thepropeller by rotation of the rudder shaft, and selectively , thetime of a low speed . On the other hand , for example, at a other rudder plate is turned from aside of the propeller to thecruising speed in a range greater than a predetermined ship 55 propeller upstream side by rotation of the other rudder shaft.
speed , performance is maintained by steering suitable for a FIG . 20 shows the turning state of the rudder plate 30 at thecruising speed according to the two - same direction mode intime of the two -same direction mode : starboard turning, and

FIG . 21 shows the turning state of rudder plates 32, 33 ataround the propeller 20 in the same direction , two propellers

the third embodiment. In the two - independent mode, athe propeller , and the rudder on a left side is turned counrudder plate 33 on a port side opposite to a starboard veering

terclockwise similarly at behind of the propeller, thereby, awhich left and right rudders take a rudder angle opposite to
motion becomes left and right inversion to this at the time ofeach other. Even in one steerage , this is a steering device porting the helm . In this case , as shown in FIG . 20 , there iswhich enables different steering by either steering mode of 60 an advantage that, when both of the two rudder plates 30
the two-independent mode or the two - same direction mode .
face each other across the propeller 20 , and are turned
the time of steering in a starboard direction at the time of take the samemotion , becoming simple , and ship handling
undocking, in which a side thrust flow is generated by the becomes easy. When a ship is faced in the right direction , thetwo - independent mode of the invention in connection with 65 rudder on a right side is moved counterclockwise in front of

US 9 ,937,992 B2

At the time of veering in the two-samedirection mode, the18stopping power. An object of this steering is to reset propeller driving, and thereafter, shorten the time during which
the propeller rotates by the inertia to enable the propeller toreversely rotate early, in the case where sudden stop is

example , in the case of starboard helm , the port side rudder
is turned from aside of the propeller to the downstream ofpropeller like this, reverse rotation of the propeller can be
stopped to accelerate reverse rotation of the propeller. In

the propeller by rotating the rudder shaft of a port side , andaddition , when both rudder plates are turned to an upstream

in the case of portside helm , the starboard side rudder isside 45° forward as a speed reducing stage at the time ofdeflected water stream in a rudder angle direction can begenerated , and the ship is turned in a rudder angle direction

by the counteraction .

rudder plate on a side opposite to a veering direction , for 5 necessary . When it is necessary to reversely rotate theturned from aside of the propeller to the up steam of the 10 initial motion of stop maneuver , both rudder plates receive

propeller by rotating the rudder shaft of a starboard side ,a water stream at a vessel speed , and a speed of a ship can

deflects a propeller slipstream along a large rudder angle , be reduced by the counterforce thereof.
provides high turning performance by a rudder force due toWhen the steering device 1 in connection with the thirda counterforce . In this case , the rudder force contribute toembodiment shown in FIG . 18 is used , since two shafts eachsteering performance by adding the turning moment to the 15 are independently driven by a hydraulic motor mechanism

ship because the rudder is positioned sufficiently isolated

from a ship center line . Selectively, the other rudder plate isturned upstream of the propeller from aside of the propeller
by rotating the rudder shaft, the rudder plate is arranged at

140, and free turning from FIG . 20 to FIG . 21 becomes

possible , it results in that there is provided the steering
device 1 that, at the time of straight cruising, rudder plates
30 are positioned on both sides of the propeller 20 without

a position sufficiently isolated from the ship center line as 20 positioning at the propeller slipstream , the effect of impartcompared with a conventional rudder, and turning of one
rudder plate in front of the propeller imparts the maneuver

ing a high propulsive efficiency is provided , and at the sametime, at the time of emergency stopping, a rudder angle

ability by a counterforce received from a water stream along

range exceeds 70 degree , the two rudder plates cooperate topropeller slipstream to contribute the ship turning ability .

ship hull 10 is imparted at the propeller slipstream to obtainthe vessel, and another rudder plate turning behind the turn around the propeller so as to almost block the propeller
propeller changes a direction of a water stream of the 25 slipstream , a rudder angle , for example , of 90 degree to a

Since the rudder is located at a position sufficiently isolated

from the ship center line, the present steering device proa high stopping power , a water stream of the propeller 20 isfreely deflected and straightened for turning a ship tovides the rudder force which contribute to steering perfor - maintain turning performance .
mance by adding the turning moment to the ship .
30 A fourth embodiment of the steering device is the caseAt the ahead condition of the ship with the two - same

where a lower portion of the reverse L - letter type rudder

direction rudder plate mode, both rudder plates are arranged

plate of the third embodiment is folded to a propeller side ,which is originated from a rudder behind a propeller, can beeffect imparted by the first embodiment by a smaller steeringand higher propulsive performance can be provided com pared with ship with a rudder located in a behind of a

trated below .
FIG . 22 is a front view including a propeller of a rudder

propeller. FIG . 7 shows the steering mode of the rudder inthe case of ahead going. Regardless of a steering mode, atplate portion of the steering device in connection with thefourth embodiment, FIG . 23 is a side view of the same, andlike the rudder plate 30 shown in FIG . 7 . An upward bald

embodiment is different from the third embodiment in theat aside of the propeller. Since the resistance component,

and a L -letter corner is also folded , and effect of realizing theeliminated , the propulsive efficiency of a ship is increased , 35 device driving mechanism is provided . This will be illus

the ahead condition of the ship , the rudder plate is arranged 40 FIG . 24 shows a perspective of the same. The fourtharrow shows a steering direction of a ship, and an upward

fine arrow of a one -dot chain line schematically indicatesflow of water. That is, in the case of straight course keeping

following points.

When a reverse L - letter type rudder plate 30 is attachedinside off-center from the rudder shaft 40 with a horizontal

ship handling , the two rudder plates 30 are retained laterally 45 portion of a L - letter type being an arm , as compared with theon both sides of the propeller 20 . At the ahead condition ofcase of an embodiment in which it is in center of the ruddera ship , two rudders are maintained on both sides of thepropeller parallel with a ship axis . Since a propeller water
stream is not obstructed by the rudders , a rudder dragshaft in a rudder plate plane in the conventional steering
device , the rotation inertia moment becomes in proportion to
the square of a turning radius, a great power mechanism forreceiving from the flow is reduced as compared with exist - 50 driving the rudder shaft is required , and disadvantage caning two rudders arrangement behind the propeller, andoccur from a view point of compatibility with a ship shape,since the rudder is not placed in a high speed rotation flowmuch as possible so that a small steering device drivingof the propeller slipstream , a noise emitted from the pro -power source may be used , a preferable steering device

higher propulsive performance can be provided . In this case ,and the economy. If the inertia moment can be reduced aspeller and rudder can be eliminated , and the additional effect 55 excellent in energy saving can be provided . When a lowerof enabling calm cruising is also obtained , and this effect is
portion of the reverse L -letter type rudder plate of thesuitable, particularly, for patrol boats, and military ships.
steering device in connection with the first embodiment
In stop maneuver, when the propeller is stopped , at a next shown in FIG . 4 is folded to a propeller side , and a mass
stage , a rudder angle exceeding 70 degree is taken in the point distance from a rudder shaft rotation center is reduced
two - independent mode, and the two rudder plates cooperate 60 by chamfering of a L - letter corner , the inertia moment is
to almost block the propeller slipstream . Selectively ; there - reduced , a driving force may be a smaller motive power
after, the propeller may be reversed . Herein , taking a rudder mechanism , and energy saving which is an object of theangle exceeding 70 degree is preferably to take a rudder present invention is realized . When the rudder plate has aangle of 90°, or a rudder angle of up to 105 degree exceeding plate -like form similar to a reverse L -letter type like this, this
this , In rudder plate arrangement shown in FIG . 10 , at the 65 is most simple configuration among a form of the rudder
time of emergency stop , two rudder plates almost block the plate in a point of integral formation , and is most advanta
propeller slipstream near the back of it to maximize a geous in regards of the strength and the economy. Integral

US 9 ,937, 992 B2
19
formation may be by any of processing such as welding
press processing , forging processing and the like , and20
110 Crank mechanism
120 Bevel gear

assembling such as bolting , riveting and the like . In thiscase , folding has the effect of increasing rigidity , decreasing

130 Electric servomotor mechanism or hydraulic motor
mechanisma plate thickness, and further reducing the inertia moment. 5 140 Rotary vane - type hydraulic motor mechanism

FIG . 25 shows a graphic view of experimental result of
the steering effort of the present invention model implemen
tation product device in the case where steering at the time

The invention claimed is :1. A steering device having a driving mechanism rotatingof the two - independentmode of a model steering device in a steering shaft, and a power mechanism driving this ,connection with the fourth embodiment is implemented . 10
wherein

Based on the following specifications , a relationshipbetween a vessel speed and a rudder force was obtained by
an experimental model.

<Specifications Around Rudder of Model Steering Device ', 15Unit mm >Propeller radium : 2400 , rudder height: 3050 , chord

length : 1500 at a height of 1950 or more from lower end ,1150 at a lowest end , a chord length linearly decreasing
towards a lower end , maximum plate thickness: 150 , steer
ing shaft central position : 600 from ship axis center, steering 20
shaft diameter: 340< Result >FIG . 25 shows a relative rudder force of a model rudder
speed in a transverse axis . It is seen that , in the two-same 25
in a longitudinal axis relative to a model ship relative vessel

the steering shaft is biaxially arranged rotatably to havevertical rotation axes located on both sides of a screw
shaft ,
two rudder plates are located lateral to a propeller at thetime of straight travelling ,each of the two rudder plates connects to the corresponding steering shaft ,each of the two rudder plates turn around the rotation axisof the corresponding steering shaft and connects to thecorresponding steering shaft, while a position of centerof the rudder plate is movable , andeach of the two rudder plates turn at least in a range fromaside of a propeller to a downstream of the propeller byrotation of the two steering shafts .

direction mode , the rudder force is increased by about 20 %as compared with the conventional single rudder , and in the

2 . The steering device according to claim 1 , wherein bothof the two rudder plates face each other across the propeller,

mode and at the time of the two - independentmode, and isprovided with a driving mechanism of the rudder supporting
this change is confirmed . When steering in the two -same

4 . The steering device according to claim 1, wherein eachrudder plate is extended laterally from the steering shaft andtwo -independent mode, the rudder force is remarkably
and turn around the propeller with a same rudder angle .
3 . The steering device according to claim 2 , wherein a
improved by 50 % , particularly , in a low speed region .
Effectiveness of the present invention which changes a 30 rudder angle range exceeds 70 degrees , and the two rudder
rudder steering method at the time of the two -same direction
plates turn so as to almost block a propeller slipstream .

of the rudder plates is formed into a L - letter type , where thedirection mode is also implemented in a low speed region , 35 then suspended downwardly .
the steering effort is inferior by 20 % to the conventional
5 . The steering device according to claim 2 , wherein themodel, and superiority of a steering method of particularly rudder plates have cambers on surfaces thereof which aresetting up a steering method in the two -independent mode opposite each other.
using the device in connection with the present invention
6 . The steering device according to claim 1 , wherein the
40 rudder plates have a limit of a chord length , which is allotted
can be confirmed .
As described above , embodiments in connection with the when one rudder plate is arranged at a propeller slipstream ,present invention have been illustrated , but the present and a wing thickness of the rudder plate is smaller than ainvention is not limited to such embodiments , and can be wing thickness allotted when one rudder plate is arranged at
implemented by various modifications in such a range not the propeller slipstream .

departing from the gist of the present invention .
INDUSTRIAL APPLICABILITY

The present invention can be applied to a steering portion45

7 . The steering device according to claim 1 , wherein thedriving mechanism performs by freely switching each modeof a two - independent mode in which the two rudder plates
are turning -driven independently of each other and a twosame direction mode in which the two rudder plates are bothof surface ships , particularly , big ships, domestic vessels and 50 turning- driven in the same direction .
patrol boats requiring quick ship handling even at a low
8 . The steering device according to claim 7 , wherein in the
speed .
two - independent mode, the rudder plate on a broadside
opposite to a veering direction is turned from aside of the
DESCRIPTION OF REFERENCE NUMBERS
propeller to behind of the propeller by rotating the steering
1 Steering device

2 Propulsive device
5 Screw shaft
10 Ship hull
11 Stern tube

12 Stern

20 Propeller
30 Rudder plate
31 Camber
40 Rudder shaft

90 Driving/Power mechanism
100 Hydraulic cylinder

shaft, and simultaneously with this , or before or after this,the other rudder plate on a broadside on a veering direction

side is turned from aside of the propeller with a rudder angleof 90 degrees behind of the propeller.
9 . A method for steering the steering device according to

60 claim 8 comprises the two - independent modes turning therudder plate on a broadside opposite to a veering direction

from aside of the propeller to behind of the propeller byrotating the steering shaft, simultaneously with this , orbefore or after this ,65 turning the other rudder plate on a broadside and veering
direction side from aside of the propeller with a rudder
angle of 90 degrees behind of the propeller , andUS 9 ,937,992 B2
after turning of the two rudder plates, further, increasing

the propeller rotational speed more than the propeller
rotational speed at the time of a ship condition withstraight course keeping .
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