US 3056374 A
Description (OCR text may contain errors)
Oct. 2, 1962 H. D. LINHARDT AUXILIARY STEERING Am PRoPULsIoN UNIT Filed Maren 2e, 1959 5 Sheets-Sheet l INV ENTOR.
@frag/VE# Oct. 2, 1962 H. D. LxNHARDT 3,056,374
AUXILIARY STEERING AND PROPULSION UNIT Filed March 26, 1959 3 Sheets-Sheet 2 M @www @frag/5% Oct. 2, 1962 H. D. I INHARDT 3,056,374
AUXILIARY STEERING AND PROPULSION UNIT Filed March 26, 1959 3 Sheets-Sheet 3 HQNS D. UNH/67,907,
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3,056,374 AUXIELEARY STERREN@ AND PRPULSiQN UNET Hans D. Linirrdt, 2h33 N. Beachwood Drive, i-loliywood 25, Calif. Filed Mar. 2e, i959, Ser. No. SliZalSl 4 Claims. (Qi. lid- 315D This invention relates to a turbine pump driven auxiliary steering and propulsion unit which in a preferred form of the invention is mounted on the rudder blade of a ship. in another form of the invention as exemplified herein, the auxiliary steering and propulsion unit may be mounted in the bow of a ship to provide a transverse reaction thrust. The purpose of the invention is to provide improved steering qualities and improved maneuverability.
The problem of steering a ship at slow speed is an old one and has not been adequately or satisfactorily solved in the prior art. A practical solution of the problem is necessary for all vessels operating in narrow waters, canals or locks, especially in strong winds, currents and going in ballast and by seagoing ships in high seas and storms. ln such operations the normal rudder is unsatisfactory as the induced forces on the rudder blade are too weak to induce sufficient steering power. Necessarily the helm angle has to be increased for the necessary reaction on the ship, resulting in an overreaction or overcontrolling to one side or the other so that the ship yaws and loses speed and otherwise does not navigate satisfactorily.
A practical and efficient steering device has been necessary which does not depend on a current produced by the ships propeller or the ships movement but which is effective when the ship has no way on and is able to turn the Vessel on the spot or in very small circles.
Having in mind the rather severe requirements for a practical and adequate solution of the problem, there has been conceived a unique auxiliary steering and propulsion unit having a pump turbine drive, the turbine being mounted on the rudder and powered by hydraulic Huid under pressure which may be sea water provided by a service pump on the ship. The particular u nit overcomes the drawbacks attendant to attempts to use other types of drive and more particularly that the unit provides an adequately flexible and eiiicient power supply for the auxiliary propeller. The particular unit provided results in a most economical speed and power control of the auxiliary propeller covering a large range of desirable operating points. in one form of the invention a variable pitch propeller is provided which in fact results in an optimum propulsion system.
The main objective of the invention is accordingly to solve the problem practically and adequately of steering a ship at slow speed and in restricted waters. More particularly it is an object of the invention to provide a unique auxiliary steering and propulsion unit which overcomes the drawbacks attendant to prior art attempts to solve the problem and which provides an appropriately flexible efficient, practical and economical steering unit.
A further object of the invention is to realize the advantages and results inherent in the following explanation.
The main effect of the auxiliary steering device is that there is always a thrust in the direction of the rudder and therefore an active rudder moment. The effect has been demonstrated by plotting the maneuverability of a particular ship with and without a steering and propulsion unit. r[he maneuverability was plotted in terms of the radius of the ships turning circle as respects speed. The advantage of the unit is obvious for slow speed operations. The entire rudder thrust can be reversed irn matenteti c't. 2, i962 mediately by a suitable power control or propeller design. Therefore the rudder does not have to be turned from hard port to hard starboard. The turning motion of the ship in rotation can also be stopped and lreversed within a short time. Special maneuvers can be carried out with the propeller of the auxiliary unit running ahead or astern, the main engine stopped or running slightly ahead or reverse. Such maneuvers are especially of interest for surveying ships, which are in need of a perfect maneuverability, remaining perfect at slow speeds and with the ship not under way. During measurements calling for an exactly i'ixed position with the ship not under way it is necessary to counterbalance all wind and current forces within the whole range of the same. With increasing wind forces and sea the thrust of the auxiliary unit has to be increased as well as the rudder angle. The thrust may be controlled by a variable pitch propeller or by means of the speed of the power source or both. Usually such conditions require a twin screw ships propulsion which is very uneconomical, both main engines working against each other to eliminate any forward or backward motion of the ship.
in addition to realization of the foregoing advantages, a further object of the invention is to stabilize the flow of water around the rudder blade by means of the auxiliary propeller. The ow behind the main propeller can be improved by the suction of the auxiliary unit mounted in line with the main screw. Mainly the dead Water region of the main propeller is improved near the hub and the contraction of the leaving jet can be avoided to some amount. The propulsion efficiency itself is improved by the propulsion body surrounding the power unit.
Another object of the invention utilizing a turbine for the auxiliary unit of a mixed llow type having a high leaving velocity is to partly recover the energy of the high leaving velocity at the auxiliary propeller located at the turbine exit.
Another object of the invention is to achieve highly flexible and eficient control by way of speed control of the service pump or by hydraulic control of the service pump which supplies highly energized fluid to the auxiliary turbine.
Another object of the invention is to relieve the load on the thrust bearings of the auxiliary turbine by balancing the propeller thrust against the turbine thrust.
in a slightly modied form of the invention two turbines are utilized rotating in the same direction and having concentric shafts. Two auxiliary propellers are provided rotating in the same direction, the iirst serving as an inducer to suppress cavitation and the second as a high speed propulsion device. Both propellers are surrounded by a nozzle for protection as well as the design approach of an impulse pump. The inducer propeller runs in a direction opposite to that of the main screw recovering some part of the energy furnished by the wake of the main propeller. Another object of the invention is to achieve and realize the results as stated inherent in the aforesaid modified form of the invention.
For some ships the auxiliary steering and propulsion unit as described in the foregoing mounted in the rudder blade is not suicient to provide the required maneuverability in small channels, locks or harbors. Such steering qualities are very important for war ships in dangerous areas. Prior art attempts to solve the problem have failed to give a solution which does not decrease the overall performance of the ship during full cruising speed. Another form of the herein invention provides a solution to the problem preferably by way of a transverse bow channel through the ship having means to produce a suitable reaction thrust in the channel for steering `and maneuvering. Model tests have been carried out investigating arredare different forms of bow channels and it has been found that very useful and surprising Steering qualities can be achieved with a straight channel as exemplified herein during high speed. During slow speed the reaction of the Water jet is used for turning; during high speed resistance of the water jet provides turning moment in the direction of the leaving water jet. A further object of the invention is accordingly to provide additional required maneuverability by means of a channel preferably at the bow in which a transverse reaction thrust is pro-- duced.
Y Further objects and numerous detailed additional advantages of the invention will become apparent from the following detailed description and annexed drawings, wherein:
FIG. l is a partial diagrammatic view of the stern of a ship having a preferred form of the herein invention embodied therein;
FIG. 2 is a partial Sectional View in detail of the auxiliary steering and propulsion unit of FIG. l;
FIG. 3 is a diagrammatic view of a modified form of auxiliary steering and propulsion unit;
FIG. 4 is a diagrammatic view of the bow of a ship having a modied form of the invention embodied therein;
FIG. 5 is a sectional View taken along the line 5-5 of FIG. 4;
FIG. 6 is a diagram or graph of thrust versus velocity for the type of installation shown in FIGS. 7 and 8;
FIG. 7 is a diagrammatic illustration of the steering effect of a unit `as shown in FIG. 5;
FIG. 8 is a similar diagrammatic illustration showing the effect of reversing the direction of flow through the unit at higher speeds;
FIG. 9 is a diagrammatic view of the ship showing the surface of the Water relative to the steering unit at relatively low speeds;
FIG. 10 is a view similar to FIG. 9 showing the water surface at higher speed; and
FIG. ll is a chart similar to that of FIG. 6 showing the effect on the thrust resulting from increasing the speed of the unit or otherwise increasing the thrust at low velocity of the ship.
FIG. l of `the drawings shows the stern part of a ship diagrammatically at 10. The main propeller of the ship is designated at lll just ahead of the rudder designated at 12. The rudder is on a rudder post 13 and the auxiliary steering and propulsion unit of the invention is designated at 16. The propulsion unit is in a faired or streamlined housing in the rudder in order to offer a minimum of hydrodynamic resistance. As will be explained hereinafter, the turbine unit is powered from the service pump on board the ship which supplies highly energized sea water to the turbine unit. The service pump itself is not shown in FIG. 1.
FIG. 2 shows part of the rudder 12 and the auxiliary steering and propulsion u nit in cross section.
The rudder 12 is essentially of standard type having a built up construction as shown including the internal struts and rib members ll7 and 1S. The rudder itself, preferably has a faired or streamlined configuration to reduce hydrodynamic resistance. The auxiliary steering and propulsion turbine as designated at is supported from internal structure 21 within the rudder and part of which is within the body 16 of the auxiliary unit.
The turbine 20 is of a mixed in-flow type, its thrust being -balanced against the thrust of the propeller which it drives. The turbine shaft is designated at 22, the shaft being journaled in bearings adjacent the ends of the shaft as indicated diagrammatically at 23 and 24. The turbine casing is indicated at 26 and it of course carries the turbine stator yor stator parts. Numeral 27 designates an inlet box which is in the form of an involute at the right end of the turbine stator and this involute communicates with an inlet pipe 30 for high pressure hydraulic fluid. The pipe or conduit 30 extends upwardly through the rudder stern which is hollow. As described, the conduit 30 connects with the service pump on board the ship.
The turbine has a closing housing 3l at the right end within which is disposed a thrust bearing comprising the disc 32 on shaft 22. The disc carries thrust ring elements 33 and 34 which cooperate with ring shaped thrust members 35 and 36 made of appropriate material.
At the right end of the shaft 22 is a variable pitch or pitch reversing unit 37 by which the pitch of the auxiliary propeller may be varied. This unit is of a type known to the art and may be controlled for example by Way of hydraulic fluid connections as shown at 40 and 41.
The turbine includes stator member 42 fixed to the casing and rotor member 43 on the shaft 22. As stated the turbine is of an ineflow type; highly energized hydraulic fluid from the involute 27 feeds to the rotor 43 at its periphery, the rotor having suitable vanes as shown. r[he fluid passes from the central portion of the rotor 43 outwardly as guided by a stator member or portion 45. The uid then flows inwardly as respects rotor 47 between this rotor and stator member 48. The flow is then again outwardly adjacent stator portion 50' and inwardly as respects rotor member 5l. The shaft 22 rotates in appropriate bearings carried by the stator portions 45 and Sil.
The turbine has an exhaust section as indicated at which is diverging as shown, having a diverging annular exhaust channel as shown at 56. The exhaust section is suitably supported in the turbine casing and provides a bearing for the shaft 22 as shown diagrammatically. The section 55 has an extending skirt as shown at 57 which terminates adjacent the propeller hub 58. The hub includes a disc S9 attached to the end of .the shaft 22 by means including a ange as shown at 60. Numeral 64 designates struts supporting the nozzle 63. The nozzle 63 is of faired or streamlined configuration to reduce hydrodynamic resistance and is of built-up construction as shown comprising the sections 65 and 66. Nozzle 68 produces some thrust according to its angle of attack.
In operation the turbine unit as described is supplied with highly energized hydraulic fluid such as sea Water from the service pump in the ship through the conduit 30. Thus a rugged and simple power supply is provided susceptible to effective speed control by a speed control of the service pump or by hydraulic control of the pump such as by inlet vane or valve control. The direction of propeller thrust may be reversed by changing the pitch of the propeller 61 by means of the variable pitch device 37. This therefore may be used in steering and maneuvering in the manner discussed in the introduction. The thrust bearings are nearly Without load because the propeller thrust is balanced against `the turbine thrust as may be seen from FIG. 2. The turbine has a relatively high leaving velocity and part of this energy is recovered by the auxiliary propeller 61 at the turbine exit. The turbine bearings are -water lubricated, water being admitted by way of the channel as shown at 68.
The torque characteristics of a system as described have been analyzed and are highly appropriate to meet the requirements. The system makes possible the use of the maximum torque most effectively for proper starting under any conditions. The system provides an economical and highly effective steering and propulsion unit which minimizes size and weight but yet offers optimum flexibility.
The speed of a unit of the type described is mainly xed by cavitation considerations. By using anti-cavitation techniques higher propeller speeds may be provided resulting in smaller dimensions, decreased hydrodynamic drag, or a desirable increase in power and thrust. The efficiency of the unit described is high; at some sacrifice in ehciencies higher propeller speeds may be utilized, making it possible to reduce the dimensions of the unit and thereby reducing the drag, that is, the hydrodynamic resistance of the turbine housing. This result is realized in a modified form of the invention shown in FIG. 3.
In FIG. 3 the rudder is shown at 72 with a turbine pump steering and propulsion unit or units designated generally at 73. There are either two turbines or a twostage turbine having concentric shafts as shown at 74 driving two propellers 75 and 76 at dierent speeds. The inlets to the turbines are shown at 77 and 78, the drive corresponding otherwise to that of the previous embodiment. The propellers rotate within a nozzle 81 which iS connected to the body 73 of the unit by strut members as shown at 82.
The unit is mounted on the rudder directly astern of and aligned with the main propeller shaft as shown in FIG. l.
Propellers 75 and 76 rotate in the same direction; however propeller 75 serves as an inducer to suppress cavitation astern of the main ships propeller. The second propeller 76 acts as a high speed propulsion device. The propeller 75 might utilize 25%, for example, of the available power. The inducer propeller 75 operates in the:
opposite rotational direction from the main propeller and recovers some part of the energy furnished by the wake of the main propeller. This form of the invention accordingly provides a unit utilizing a higher propeller speed, in which cavitation is suppressed and the overall size of the unit being smaller to lessen the drag. Two lightly loaded counter-rotating propellers may also be used.
FIGS. 4 and 5 show another form of the invention exemplifying application of its principles in a slightly different way. In FIG. 4 there is shown diagrammatically the bow or forward part of a ship having a transverse ow channel S5 therein which is shown more in detail in FIG. 5. In FIG. 5 there is shown in cross section the lower part of the hull 86 of a ship. The ship has decks as shown at S7 and 88 and watertight compartments as shown. The channel 85 is preferably near the bow of the ship but not necessarily so. This channel is formed to be extending transversely of the hull of the ship as shown and structurally may be built in any appropriate manner using structural techniques already known in the art. 'Ihe keel or bilge of the ship is shown at 91 and as shown in FIG. 5 control means are provided at the. end of the channel 85 in the form of adjustable louvres as shown at 92. The louvres 92 may be adjusted by means of any suitable and appropriate steering control apparatus already known in the art.
Mounted in the channel 85 is a turbine pump or thrust producing unit as shown at 94 which may preferably be of the type shown in FIG. 2. It is to be understood how ever that other types of thrust reaction units might be utilized in the channel S5.
The form of the invention as shown in FIGS. 4 and 5 is useful to provide the required maneuverability in small channels, locks or harbors. Such steering qualities are very important for war ships in dangerous areas. Tests have shown that the type of channel as shown in FIGS. 4 and 5 performs highly successfully. Speed control of the turbine or the like and a variable pitch propeller may be utilized as discussed in connection with the previous ern bodiments. The channel 85 may also be curved downward or toward or against the ow direction that is the ow of water passing the ship. Very useful and surprising steering qualities can be achieved with a straight channel as shown in FIGS. 4 and 5 when operating at high speed. The auxiliary propeller operates heavily loaded during low speeds of advance. Preferably the propeller or propellers used are of a type combining a pump and propeller concept to operate efficiently at lower speeds. The principle of the invention however and its actual practical application are fully illustrated in FIGS. 4 and 5 taken with the herein description.
FIGS. 6 to ll illustrate the useful and surprising steering qualities that can be realized with the channel as shown in FIGS. 4 and 5 when operating at high speed.
FIG. 7 illustrates diagrammatically the bow of a ship 86 having a straight transverse channel 85 with a unit 94 therein which may for example be of the type shown in FIG. 2. FIG. 7 illustrates the flow of water past the ship and the flow of water through the channel when the ship or vessel is moving at a relatively low velocity V. The velocity of the water through the channel 85 is indicated by v. The ilow of water through the channel is indicated by the arrow and the direction of the thrust which produces steering moment is indicated by T. FIG. 7 also indicates the general direction of movement of water entering and leaving the channel 85. These conditions as represented are for relatively low velocities of the ship.
FIG. 6 is a chart or graph of velocity of the ship versus thrust produced by the unit 94 as shown in FIG. 7. As may be seen in FIG. 6 as the velocity of the ship increases at a given power of the unit 94 the thrust at a certain point as shown drops off rather abruptly and in fact will drop to zero `as shown. This effect has been discovered in actual test and it is a part of this invention, knowing this condition to reverse the direction of iiow through the channel 85 at or substantially at the zero point as illustrated in FIG. 8 and as further illustrated in the graph FIG. 6. As shown in FIG. 8 the flow of water through the channel 85 has been reversed the ship 86 now moving at a relatively higher velocity. The effect now is that the water leaving the channel 85 jets out into the sea and actually has the effect of a steering member being thrust out in that direction. In other words the thrust T remains in the direction shown in FIG. 8 after reversing the direction of flow through the channel 85. The reversal of the direction of ow may of course be achieved by reversing the direction of rotation of the unit 94.
FIGS. 9 and l0 illustrate diagrammatically the surface of the water as respects the bow of the ship when the ship is moving at relatively low speed as shown in FIG. 9 and at relatively higher speed as shown in FIG. l0. As shown in FIG. l0 at the higher speeds the surface of the Water has the general shape shown tending to form a depression or cavity aft of the channel S5. From this the effect described in FIG. 8 can be understood.
It may of course be desirable to not allow the thrust T or steering moment drop all the way to zero. This may be accomplished of course with reference to FIG. 7 by for example speeding up the unit 94 before the zero thrust point is reached as is illustrated in the chart or graph of FIG. ll. Thus as shown the thrust is not allowed to drop to `zero but rather the curve has a horizontal low portion as shown in the figure.
In regard to FIGS. 6 to ll different types of units may of course be used in the channel 85 and the desired control effects may be achieved by reversals in direction of rotation, changes in speed or changing the pitch of the propeller or propellers of the unit 94. The ends of the channel 85 may be controlled by flaps or louvers 92 as shown in connection with FIG. 5.
From the foregoing those skilled in the art will observe that the forms of the invention disclosed are practical embodiments thereof which in the manner explained achieve and realize the results, objectives and advantages heretofore outlined. The invention solves a problem and meets a need which has not heretofore been practically or adequately met.
The foregoing disclosure is representative of preferred forms of the invention and is to be interpreted in an illustrative rather than a limiting sense. Various modifications and alternatives may occur to and be adopted by those skilled in the art, all within the realm and spirit of the invention, which is to be accorded the full scope of the claims appended hereto.
What is claimed is:
l. In combination with a propeller and steering member attached to a ship, an auxiliary steering and propulsion unit comprising a uid powered axial 110W turbine carried by the steering member and a propeller driven by the turbine, positioned to have the turbine discharge through it.
2. The combination of claim 1 wherein the said auxiliary unit is mounted on the steering member in a position such that in mid-position of the steering member the auxiliary unit is directly astern of and aligned with the driving propeller of the ship.
3. The :combination of claim 1 including nozzle means positioned around the said propeller driven by the turbine.
4. The combination of claim 1 including means for varying the pitch of the propeller driven by the said turbine. l
References Cited in the le of this patent UNITED STATES PATENTS Pratt May 19, 1931 Cogswell Oct. 13, 1942 Briggs Sept. 28, 1943 Katcher et al Nov. 21, 1944 Frasure Oct. 27, 1953 Waterval Oct. 16, 1956 SWan Sept. 2, 1958 OTHER REFERENCES The British Motor Ship, September 1952, page 239.