WO1992017366A1 - Bateau rapide monocoque - Google Patents

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Publication number
WO1992017366A1
WO1992017366A1 PCT/US1992/002568 US9202568W WO9217366A1 WO 1992017366 A1 WO1992017366 A1 WO 1992017366A1 US 9202568 W US9202568 W US 9202568W WO 9217366 A1 WO9217366 A1 WO 9217366A1
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WO
WIPO (PCT)
Prior art keywords
ship
hull
waterjet
accordance
high pressure
Prior art date
Application number
PCT/US1992/002568
Other languages
English (en)
Inventor
David Laurent Giles
Original Assignee
Thornycroft, Giles & Co., Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/678,646 external-priority patent/US5129343A/en
Application filed by Thornycroft, Giles & Co., Inc. filed Critical Thornycroft, Giles & Co., Inc.
Priority to JP4510628A priority Critical patent/JPH06503290A/ja
Priority to KR1019930702962A priority patent/KR970006351B1/ko
Publication of WO1992017366A1 publication Critical patent/WO1992017366A1/fr
Priority to NO933510A priority patent/NO933510D0/no
Priority to FI934304A priority patent/FI934304A0/fi

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
    • B63B1/04—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H11/00—Marine propulsion by water jets
    • B63H11/02—Marine propulsion by water jets the propulsive medium being ambient water
    • B63H11/04—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps
    • B63H11/08—Marine propulsion by water jets the propulsive medium being ambient water by means of pumps of rotary type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H21/00—Use of propulsion power plant or units on vessels
    • B63H21/12—Use of propulsion power plant or units on vessels the vessels being motor-driven
    • B63H21/16—Use of propulsion power plant or units on vessels the vessels being motor-driven relating to gas turbines

Definitions

  • the present invention relates to a fast ship whose hull design in combina1y.on with a waterjet propulsion 5 system permits, -for ships of about 25,000 to 30,000 tons displacement with a cargo carrying capacity of up to 10,000 tons, transoceanic transit speeds of up to 37 to 50 knots in high or adverse sea states, speeds heretofore not achievable in ships of such size without 10 impairment of stability or cargo capacity or constructed at such prohibitive cost as to render them commercially or militarily unviable.
  • a major limitation of present day 30 displacement hulls is that, for a given size (in terms of displacement or volume) , their seaworthiness and stability are reduced as they are "stretched" to a greater length in order to increase maximum practical speed.
  • Traditional hull designs inherently limit the speed with which large cargo ships can traverse the ocean because of the drag rise which occurs at the "threshold speed". This is a speed (in knots) which is about equal to the square root of the ship's length (in feet) .
  • a mid-size cargo ship at about 600 feet length has an economical operating speed of about 20 knots or some 4 knots below its design threshold speed.
  • Dr. Froude first accurately measured and defined the phenomenon by which increased length is required for higher ship speeds because of the prohibitive drag rise which occurs at a threshold speed corresponding to a length Froude Number of 0.3.
  • the length Froude Number is defined by the relationship 0.298 times the speed length ratio I N L J , where V is the speed of the ship in knots and L is the waterline length of the ship in feet.
  • a Froude number of 0.298 equates to a speed length ratio of 1.0.
  • Froude*s teaching to go faster for the same volume the ship must be made longer, thus pushing the onset of this drag rise up to a higher speed.
  • the power required for a 300 foot planing frigate to achieve its minimum practical speed (60 knots) would be about half a million horsepower; but currently such horsepower cannot be installed, let alone delivered in a ship of such small size and low displacement.
  • the ensuing ride on this 300 foot ship would cause material fatigue as its large flat hull surfaces would be slammed at continuously high speed into the ocean waves inasmuch as it would be too slow to plane or "fly" across the waves as a much smaller planing craft would do.
  • the planing hull incorporates, typically, a combination of very high power, flat or concave “vee'd” bottom sections, often incorporating warped surfaces, with an angular section or “chine” at the conjunction of the sides and bottom portion, necessary for clean flow separation giving enhanced aquaplaning capabilities and imparting higher stability at very high speeds. It also characteristically features an extremely lightweight structure of wood, aluminum or fiberglass.
  • U.S. Patent 2,185,430 ( . Starling Burgess) describes one of many interpretations of this type of hull, of which the inventor claims "one and a principal object ...
  • Hull designs using the concept of hydrodynamic lift are known with regard to smaller ships, e.g. below 200 feet or 600 tons powered by conventional propeller drives as shown in U.S. Patent No. 2,242,707.
  • the shape of this hull is such that high pressure is induced under the hull in an area having a specific shape to provide hydrodynamic lift.
  • the monohull fast ship develops hydrodynamic lift above a certain threshold speed as a result of the presence of high pressure under the aft part of the hull and also in the upper surfaces of the inlet pipes for the waterjets shown in Fig. 16.
  • Such a hull reduces the residuary resistance of the hull in water as shown in Figs. 11 and 14 described below. Therefore, power and fuel requirements are decreased.
  • hydrodynamic lift increases as the square of the velocity, a lifting hull allows higher speeds to be achieved than a traditional hull which tends to "squat" or sink at speeds above a Froude number of 0.42 or a speed length ratio of 1.4.
  • Troyer Since Troyer teaches no information concerning size, proportions, displacement, speed or power, or their interrelationship, the size or type of craft or purpose of his craft cannot be determined. However, he does teach a "specific form of stern design" for a “boat” with “pointed bow and stern portions”.
  • the Troyer stern has, characteristically, a rounded or pointed plan-form, a chine or sharp angle at the conjunction of the bottom portion and sides below the waterline; and angles of deadrise at the stern which are greater than 10°. In these important features it diverges from the design features set out for the present invention as discussed below.
  • the major feature of Diry's teaching is: "a high speed displacement hull in which a substantial portion of length comprises a parallel midbody of constant and full section.”
  • the characteristics of the hull shape contribute to seakeeping qualities as well as the reduced resistance of the hull at high speed. 6. Wherein sufficient power can be delivered using existing marine gas-turbine machinery coupled with waterjet propulsors based on those which, increasingly, are proving efficient and practicable in smaller high speed craft today. 7. Wherein the weight and cost of the structure, powerplants, propulsors, gearboxes, fuel and outfit are not so high as to prohibit the operation of a commercially viable transoceanic service carrying a combination of containerized and/or Roll-on/Roll-off cargo.
  • the MFS generic design of the present invention is operating in the most difficult speed regime, in which hull-form is important in achieving the foregoing characteristics of the present invention.
  • the speed is insufficient to enable the ship fully to aquaplane, or "fly".
  • the speed is too high to allow proven design techniques for traditional displacement hulls to be employed.
  • Such techniques necessary to reduce frictional resistance and delay the onset of prohibitive residuary or "wavemaking" resistance, are in fact quite contrary to the requirements of both hull and waterjet efficiency within and beyond the defined “threshold" speed. This particularly applies in a ship with the low length beam ratio, wide transom and high displacement ratio of the present invention.
  • this intermediate speed regime such as between 40 to 50 knots features of the hull-form are significant to the technological and commercial viability of the invention.
  • the present invention overcomes the problems and limitations encountered in prior art hull designs and propulsion systems for fast commercial ships in excess of 2000 tons and pleasure craft in excess of 600 tons.
  • the present invention provides of a fast yet large commercial ship such as a cargo ship or vehicle ferry in excess of 2000 tons which, by high speed without prohibitive power attains a greater turnover on investment to offset the higher capital and operating costs.
  • the present invention achieves a seaworthiness in open ocean conditions superior to that of current commercial ship and pleasure craft designs.
  • the present invention provides a greater frequency of service per ship and less need to visit several ports on each side of an ocean crossing to increase the cargo loaded onto a ship of sufficient length and size necessary to achieve the high speed required to reduce crossing time significantly.
  • the present invention attains a wider operating speed envelope which allows more flexible scheduling and greater on-time dependability.
  • the present invention provides a commercial ship with smaller or shallow harbor access and greater maneuverability than the prior art of similar tonnage, thanks to having waterjets and a built-in trimming or fuel transfer system rather than conventional underwater appendages such as rudders or propellers.
  • the present invention may be configured in a commercial ship having a waterline length (L) of about 680 feet, an overall beam (B) of about 115 feet, and a full load displacement of about 25,000 to 30,000 tons.
  • L waterline length
  • B overall beam
  • a full load displacement of about 25,000 to 30,000 tons is generally applicable to pleasure craft in excess of 600 tons and 200 feet and commercial ships in excess of 2000 tons.
  • a system employing wing waterjets may be used.
  • the wing waterjets can incorporate a reversing system. As a result, a ship utilizing my inventive concept will be maneuverable at standstill.
  • the present invention utilizes a known MFS design with inherent hydrodynamic lift and low le ⁇ gth-to-beam ( /B) ratio but in a heretofore unknown combination with gas turbine power and waterjet propulsion which requires, for best efficiency, high pressure at the inlet of the waterjets which corresponds to the stern area of the MFS where high pressure is generated to lift the hull.
  • An advantage of a waterjet propulsion system in the MFS hull is its ability to deliver large amounts of power at high propulsive efficiency at speeds of over 30 knots and yet decelerate the ship to a stop very quickly.
  • the system also largely eliminates the major problems of propeller vibration, noise and cavitation.
  • a principal advantage of the integrated MFS and waterjet system is that the shape and lift characteristics of the hull are ideal for the intakes and propulsive efficiency of the waterjet system, while the accelerated flow at the intakes also produces higher pressure and greater lift to reduce drag on the hull even further.
  • the MFS hull is ideally suited for waterjet propulsion.
  • a highly efficient propulsion system, combined with gas turbine main engines, can be provided to meet the higher power levels required for large, high speed ships.
  • the low length-to-beam ratio of the present invention provides for greater usable cargo weight and space and improved stability.
  • the waterjet propulsion system provides greater maneuverability than with propellers due to the directional thrust of the wing waterjets and the application of high maneuvering power without forward speed.
  • the waterjet propulsion units or pumps driven by marine gas turbine units of the present invention produce an axial or mixed flow of substantial power without the size, cavitation and vibration problems inherent in propeller drives.
  • Reduced radiated noise and wake signatures are produced by the invention due to the novel hull design and waterjet propulsion system.
  • the MFS hull may be economically produced in available commercial shipyards.
  • Marine gas turbine engines which are used by the present invention presently produce, or are being developed, to produce greater power for a lower proportional weight, volume, cost and specific fuel consumption than has been available with diesel or steam powered propeller drives.
  • the MFS hull underwater shape avoids the traditional drag rise in merchant ships. Due to the
  • the stern of the ship begins to lift (thereby reducing trim) at a speed where the stern of a conventional hull begins to squat or sink.
  • the present invention combines the power and weight efficiencies of marine gas turbines, the propulsive efficiency of waterjets, and the hydrodynamic efficiency of a MFS hull shaped to lift at speeds where traditional hulls squat.
  • the present invention finds particular utility for maritime industry vessels in excess of approximately 200 feet overall length, approximately 28 feet beam and 15 feet draft and approximately 600 tons displacement.
  • a merchant ship would utilize eight conventional marine gas turbines of the type currently manufactured by General Electric under the designation LM 5000 or LM 6000 and four waterjets of the general type currently manufactured by Riva Calzoni or KaMeWa.
  • the waterjet propulsion system has pump impellers mounted at the transom and water ducted to the impellers from under the stern through inlets in the hull bottom just forward of the transom.
  • the inlets are disposed in an area of high pressure to increase the propulsive efficiency of the waterjet system.
  • the acceleration of flow created by the pumps within the inlet pipes produces additional dynamic lift which also increases the efficiency of the hull.
  • the result is an improvement in overall propulsive efficiency compared to a hull with a conventional propeller propulsion system, with the most improvement in propulsion efficiency beginning at speeds of about 30 knots.
  • Maneuvering is accomplished with two wing waterjets, each wing jet being fitted with a horizontally pivoting nozzle to provide angled thrust for steering.
  • a deflector plate directs the jet thrust forward to provide stopping and slowing control.
  • Steering and reversing mechanisms are operated by hydraulic cylinders positioned on the jet units behind the transom. Alternatively, conventional rudders can be used.
  • a ship in accordance with the present invention will be able to transport up to 10,000 tons of cargo at an average speed of 37 to 45 knots across the Atlantic Ocean in about 3 to 4 days in sea states up to 5, with a 10% reserve fuel capacity.
  • An integrated control system may be provided to control gas turbine fuel flow and power turbine speed, and gas turbine acceleration and deceleration, to monitor and control gas turbine output torque, and to control the waterjet steering angle, the rate of change of that angle, and the waterjet reversing mechanism for optimum stopping performance.
  • Such a system may use as inputs parameters which include ship speed, shaft speed, gas turbine power output (or torque) .
  • the foregoing control system will allow full steering angles at applied gas turbine power corresponding to a ship speed of about 20 knots. It will progressively reduce the applied steering angle automatically at higher power and ship speeds and further allow full reversing of the waterjet thrust deflector at applied gas turbine power corresponding to a ship speed of around 20 knots. Moreover, the control system will automatically limit waterjet reversing deflector movement and rate of movement at higher power and control the gas turbine power and speed to be most effective at high ship speeds.
  • the present invention has the following advantages:
  • a length-to-beam ratio (the waterline length in feet divided by the maximum waterline width, or beam, in feet, expressed as L/B) of between 5 and 7.5.
  • a specific power (the shaft horsepower divided by the product of the displacement in long tons and the speed in knots, expressed as SHP/DxV) of less than 1.0.
  • the bottom portion of the hull having a longitudinal profile which is non-convex relative to the center of the ship, the contour of which depends on the normal operating speed and displacement of the ship, rising from a point of maximum depth forward of the longitudinal center of the hull to a point of minimum depth at the transverse stern or transom, such minimum depth being less than 60% of the maximum depth.
  • the transom width at the datum waterline being at least 85% of the maximum width of the hull at the datum waterline.
  • transverse sections of the hull from about 30% of the ship's length aft of the forward perpendicular (or conjunction of the stem with the datum waterline) to the stern, being rounded at their conjunction with the sides of the hull and being non-concave in section on each side of the keel or centerline, except for those of about the forward 25% of the ship's length, which are concave and meet the sides of the hull in a "knuckle".
  • the maximum angle of deadrise (the angle between the upward slope of the bottom transverse sections and horizontal) at the transom being less than 10°.
  • the present invention would require less than one-half of the power disclosed for the Burgess hull at the same scaled speed.
  • the Burgess hull would only exhibit a maximum displacement of 14,136 tons but still require some 3,000,000 Shaft H.P. for its minimum design speed of 65 knots, assuming the same specific power as in the earlier example.
  • the present invention achieves a speed well within its intended performance regime, whilst carrying the necessary commercial cargo.
  • the present invention shows an underbody rising from a point of maximum depth to a point of minimum depth, at the transom, which is only some 20% of the maximum.
  • Burgess teaches an almost level underbody profile - which may be derived from the necessity of maintaining a longitudinal center of buoyancy far aft of amidships, as is necessary at very high speed and as discussed in his text.
  • transom width is a major physical requirement of the present invention in providing the desired speed of operation such as 40 to 50 knots since transom width limits the size and hence power of both waterjets and propellers. Since Burgess teaches a considerably narrower transom relative to his maximum hull width, yet requires considerably more power at speeds within the regime of the present invention, his hull is unsuitable for waterjet propulsion at any size above small craft.
  • the transverse sections of the Burgess hull differ from those of the present invention, as expected from a hull which is intended for a much higher proportional operating speed or speed length ratio. His sections have a hard chine throughout the underwater section, combined with concave bottom sections on either side of the keel. His waterline in plan-form, at datum, exhibits a concavity, or "wasp-like waist" as he describes it.
  • the deadrise angle at the stern of the Burgess hull is about twice that of the present invention.
  • the Burgess hull is, in physical terms as in operational terms, different than from that of the present invention in that his hull is intended to be used for a totally different purpose, at smaller scale, and at much higher proportional speed than the present invention.
  • Diry's hull is contrary to the hull of the present invention, which features a hull of continually changing section; indeed, no portion of length of the hull is constant in section at any point. Diry also teaches that the entry of the vessel is formed in a particularly unique manner. It is defined by a ramp sloping upwardly from the centerline of the hull bottom toward the waterline at the bow. The slope of this ramp is preferable between 1:16 and 1:12. The ramp extends over at least one-half the length of the entry section.
  • Diry's teaching is a convex curve in profile relative to the longitudinal center line of the ship.
  • the bow sections of the present invention are concave relative to the longitudinal center line of the ship and sharply pointed at the keel - rather than convex and flat at the keel, as in Diry's Fig. 5 - in the area about 30% of the ship's length aft of the forward perpendicular, which is similar in proportion to Diry's "entry length”.
  • Diry's hull and the present invention are divergent in these three important aspects.
  • Diry teaches that his hulls are intended to operate in the Froude number range of 0.6 to 1.20.
  • Fig. 11 shows a shaft horsepower comparison between an MFS frigate (curve A with the circle data points) and a traditional frigate hull (curve B with the triangular data points) of the same length/beam ratio and 3400 tons displacement. Between about 15 and approximately 29 knots both ships require similar power. From 38 up to 60 knots the MFS would operate within the area of its greatest efficiency and benefit increasingly from hydrodynamic lift. This speed range would be largely beyond the practicability for a traditional displacement hull unless the length of a displacement hull was increased substantially in order to reduce speed length ratio or the length to beam ratios were substantially increased.
  • Hydrodynamic lift in an MFS design is a gentler process which is more akin to a high speed performance sailing boat than the planing hull which is raised onto the plane largely by brute force.
  • An MFS does not fully plane and thereby avoids the problem of slamming against waves at high speeds.
  • Fig. 13 shows a continuum of sizes of semi-planing hulls, small to very large.
  • the MFS is similar in hull form to that which is widely used today in small craft because it offers the possibility of using a displacement length ratio approaching that of displacement hulls and maximum speeds approaching that of planing hulls.
  • the present invention does not employ the arrangement taught by Kobayashi because of the impossibility of achieving a balanced flow into each pipe when two or more inlet pipes are disposed in tandem. Furthermore, the heel angle of a ship of the size of the present invention is very moderate, compared with such a small boat as Kobayashi teaches; and the high water pressure under the stern and at the outboard inlets will further reduce such a possibility of ventilation.
  • the waterjet inlet pipes are disposed alongside each other, in parallel at the most favorable point in the high pressure area generated under the aft portion of the ship. Due to the inherent wide beam or low length beam ratio, and the wide transom design, there is more space available for implementing this arrangement, thus increasing the proportional limiting maximum power which can be delivered by the waterjets. This is a significant feature of the present invention.
  • the tandem inlet arrangement taught by Kobayashi is not applicable to the present invention.
  • Fig. 1 is a side elevational or profile view of the starboard side of a ship in accordance with the present invention
  • Fig. 2 is a top plan view of the ship shown in Fig.l;
  • Fig. 3 is a front elevational view viewed from the bow, of the ship shown in Fig. 1;
  • Fig. 4 is a presentation of the sections of the hull showing different contour lines at stations along the length of the hull shown in Fig. 1, half from the bow section and half from the stern section;
  • Fig. 5 is a cross-sectional view of the midship section of the hull shown in Fig. 1 to show the arrangement of the decks;
  • Figs. 6 and 7 are respectively schematic side elevational and top views showing the arrangement of the water propulsion/gas turbine units within the ship shown in Fig. 1;
  • Figs. 8A through 8D are schematic plan views similar to Fig. 7 showing alternative embodiments of the gas turbines and gear boxes;
  • Fig. 9 is a graph showing the relationship between displacement and speed with about 380,000 delivered horsepower (DHP) ;
  • Fig. 10 is a graph showing the relationship between ship speed and delivered horsepower (DHP) for the MFS described hereinbelow;
  • Fig. 11 is a graph showing a comparison of shaft horsepower/speed characteristics between the frigate ship of the present invention and a conventional frigate;
  • Fig. 12 is a graph comparing the specific power per ton/knot of conventional vessels in terms of their length with that of the present invention
  • Fig. 14 is a graph of specific residuary resistance in relation to ship speed demonstrating that a 679 foot waterline length MFS of the present invention provides reduced drag at increased absolute speed, speed length ratio and Froude Number, compared with conventional displacement hulls of the Taylor Standard Series of the same length, beam and displacement;
  • Fig. 15 is a schematic view showing the waterjet propulsion system used in the ship depicted in Figs. 1-3;
  • Fig. 16 is a schematic view similar to Fig. 6 but showing a modified gas turbine/electric motor drive for the waterjet propulsion system
  • Fig. 17 is a graph based on actual scale model tank tests of a 90 meter, MFS hull of 2870 tons displacement showing how the trim of that hull is optimized by moving the longitudinal center of gravity (L.C.G.) in units of feet forward and aft of midships (station 5 of Fig. 4) designated by the numeral "0" on the abscissa "to minimize effective horsepower (E.H.P.) absorbed at different ship speeds;
  • L.C.G. longitudinal center of gravity
  • E.H.P. effective horsepower
  • Fig. 18 is a graph based on actual scale model tank tests of the 90 meter, MFS hull of the present invention of 2870 tons displacement referred to above showing the reduction in E.H.P. absorbed where optimized trim is employed;
  • Fig. 19 is a schematic diagram of an embodiment of a fuel transfer system for optimizing trim in the MFS according to the present invention.
  • a ship designated generally by the numeral 10, having a semi-displacement or semi-planing round bilge, low length beam ratio (L/B) hull form utilizing hydrodynamic lift at high payloads, e.g. up to 10,000 tons for transatlantic operation at speeds in the range of 40 to 50 knots.
  • the L/B ratio is preferably between about 5.0 and 7.5.
  • the ship has a waterline length over 215 feet and, as illustrated in Fig. 4, a datum waterline length of 679 feet and a displacement length ratio between 60 and 150.
  • the ship 10 has a hull 11 known as a semi-planing round-bilge type with a weather deck 12.
  • a pilot house superstructure 13 is located aft of amidships to provide a large forward deck for cargo and/or helicopter landing, and contains accommodations, living space and the controls for the ship as well as other equipment as will be hereinafter described.
  • the superstructure 13 is positioned so as not to adversely affect the longitudinal center of gravity.
  • a commercial vessel is depicted in the form of a cargo ship in excess of 2000 tons displacement such as but not limited to 20-30 thousand tons, the present invention is also applicable to pleasure craft in excess of 600 tons.
  • the longitudinal profile of the hull 11 is shown in Fig. 1, while the body plan is shown in Fig. 4.
  • a base line 14 shown in dashed lines in Fig. 1 depicts how the bottom 15 of the hull 11 rises from a point of maximum depth towards the stern 17 and flattens out at the transom 30.
  • the bottom 15 of the hull has a non- convex longitudinal profile with respect to the baseline 14 from the point of maximum depth 66 to the point of minimum depth 67.
  • This contour is also illustrated in sectional form in Fig. 4 and runs from a maximum depth (Fig. 4 ref. 66) to a point of minimum depth at the transom (Fig. 4 ref. 67) which is less than 60% of the depth at point 66, in order to provide the necessary high pressure for exceeding the threshold speed without incurring prohibitive transom drag at lower length Froude Numbers.
  • Fig. 4 is a presentation of the sections of the MFS hull form of 679 feet datum waterline length with the right side showing the configuration at the forward section of the ship and the left side showing the configuration at the aft section.
  • the drawing describes the cross-section of the MFS hull in terms of meters from the beam center line and also in tenths of the ship's length from the forward perpendicular 68 to the aft perpendicular 75.
  • the MFS hull has a traditional displacement hull shape with a keel in the forward section and a flattened bottom in the aft section. In smaller vessels, a centerline vertical keel or skeg 65 shown in phantom lines in Fig.
  • the distance between the ship's centerline (68) and its conjunction with the ship's side (69) is at least 85% of the distance between the centerline (68) and the point of maximum beam (70) .
  • Station or Contour lines numbered 0-2 in Fig. 4 show the non-convex form of hull shape with associated "knuckle" in the bow section 16 viewed from right to left in Fig. 1, whereas the station or contour lines numbered 3-10 show how the bilge in the stern section 17 becomes progressively convex and flattened as also viewed from right to left in Fig. 1.
  • the acute angle between the countour line 10 (transom) at the point of intersection with a horizontal transverse datum line is a maximum of 10".
  • the ship, as illustrated in Fig. 4, has a maximum operating speed of above 34.5 knots and has a maximum displacement of over 600 tons.
  • the round-bilge hull 11 thus has a "lifting" transom stern 17 which, as is known, is produced by the hydrodynamic force resulting from the hull form which is generally characterized by straight entrance waterlines, rounded afterbody sections typically rounded at the turn of the bilge and non-convex aft buttock lines terminating sharply at the transom.
  • This type of hull is not a planing hull.
  • the hull 11 is also provided with an access ramp 18 amidship on the starboard side and a stern roll-on/roll-off ramp 19 so that cargo stored at the three internal decks 21, 22, 23 below the weather deck 12, as illustrated on the midship section shown in Fig. 5, having interconnecting lifts (not shown) can be accessed simultaneously for loading and unloading.
  • Other access ramps can be strategically located such as a ramp 20 provided on the starboard side aft.
  • the hull will achieve required structural strength with greater ease than a long, slender ship for a given displacement.
  • the shape which produces hydrodynamic lift in the MFS hull is well known and its dimensions can be determined by requirements of payload, speed, available power and propulsor configuration.
  • a three-dimensional hull modeling computer program of a commercially available type can generate the basic MFS form with the foregoing requirements as inputs.
  • an estimate of the displacement can be made using, for example, two-digit analysis with weight codings from the standard Shipwork Breakdown Structure Reference 0900-Lp-039-9010.
  • the shorter hull produces a higher natural frequency which makes the hull stiffer and less prone to failure due to dynamic stress caused by waves. while allowing, in combination with the propulsion system hereinafter described, achievement of speeds in the 40 to 50 knot range.
  • Figs. 6 and 7 illustrate schematically one embodiment of the waterjet/gas turbine propulsion system. In particular, four waterjet propulsors 26, 27, 28, 29 (one of which is illustrated in Fig.
  • the two outermost waterjets 26, 27 are wing waterjets for maneuvering and ahead thrust.
  • Each of the wing waterjets 26, 27 is provided with a horizontally pivoting nozzle 34, 35, respectively, which provides angled thrust for steering.
  • a deflector plate (not shown) directs the jet thrust forward to provide for stopping, slowing control and reversing in a known manner.
  • Steering and reversing mechanisms are operated by hydraulic cylinders (not shown) or the like positioned on the jet units behind the transom.
  • the hydraulic cylinders can be powered by electrical power packs provided elsewhere in the ship.
  • the waterjet propulsion and steering system allows the vessel to be maneuvered at a standstill and also to be decelerated very rapidly.
  • General Electric*s LM 5000 require no more than two turbines, each rated at 51,440 HP in 80° F ambient conditions, per shaft line through a conventional combining gearing installation.
  • Eight paired conventional marine gas turbines 36/37, 38/39, 40/41, 42/43 power the waterjet propulsion units 26, 28, 29, 27, respectively, through combined gear boxes 44, 45, 46, 47 and cardan shafts 48, 49, 50, 51.
  • Four air intakes (only two of which 52, 53 are shown in Figs. 1 and 6) are provided for the turbines 36 through 43 and rise vertically above the main weather deck and open laterally to starboard and port in the superstructure 13 provided in the aft section.
  • Eight vertical exhaust funnels 54, 55, 56, 57, 58, 59, 60, 61 (Figs. 2 and 6) for each gas turbine also extend through the pilot house superstructure 13 and discharge upwardly into the atmosphere so as to minimize re-entrainment of exhaust gases.
  • the exhaust funnels can be constructed of stainless steel and have air fed therearound through spaces in the superstructure 13 underneath the wheelhouse.
  • the gas turbine arrangement can take several forms to achieve different design criteria.
  • the parts in Figs. 8A-8D which are similar to those shown in Fig. 7 are designated by the same numerals but are primed.
  • Fig. 8A shows one embodiment where only four pairs of in-line gas turbines to obtain smaller installation width.
  • a gear box is provided intermediate each pair of in-line turbines. This arrangement results in a somewhat greater installation length and a higher combined gear box and thrust bearing weight for each shaft.
  • Fig. 8B is an embodiment which reduces the installation length where installation width is not deemed essential.
  • Combined gear box and thrust bearing weight per shaft is also reduced to a minimum and to a like amount as the embodiment of Fig. 8D where installation width is somewhere between the embodiments of Figs. 8A and 8C.
  • the embodiment of Fig. 8C has the gas turbines in two separate rooms to reduce vulnerability.
  • Fig. 9 demonstrates the relationship between ship speed in knots and displacement in tons. At constant DHP and waterjet efficiency, speed increases as displacement falls.
  • Fig. 10 shows, however, that a linear relationship exists at speeds above 35 knots between delivered horsepower for a vessel of 22,000 tons displacement and ship speed, assuming a certain percentage of negative thrust deductions at certain speeds. For example, to achieve a ship speed of 41 knots, required delivered horsepower will be about 380,000 according to present tank tests.
  • the prior art of Burgess teaches a specific power of 3.0 at a defined minimum speed of 65 knots at the same scale as the 679 feet MFS of the present invention. This is some seven times the specific power of the present invention at 45 knots, or ten times the specific power of accepted modern naval hulls of the same size at 30 knots.
  • Fig. 13 demonstrates the difference between the minimum Froude Number (3) for which the present invention is optimized and the minimum Froude Numbers taught by Burgess (1) and Diry (2) .
  • the optimum speed range of the MFS is of a lower Froude Number which poses very different problems such as the relationship of hydrodynamic lift to transom drag, displacement length ratio versus length beam ratio and other questions which are not addressed by the prior art.
  • the MFS in accordance with my invention also incorporates a fuel system which enables the ship to operate at optimum trim or longitudinal center of gravity (L.C.G.) to obtain minimum hull resistance in terms of absorbed E.H.P. according to speed and displacement.
  • L.C.G. longitudinal center of gravity
  • This is achieved either by the arrangement of the fuel tanks in such a way that, as fuel is burned off and speed consequently increased, the LCG progressively moves aft or by a fuel transfer system operated by a monitor with displacement and speed inputs as shown schematically in Fig. 19 in which fuel is pumped forward or aft of midships (station 5 in Fig. 4) by a fuel transfer system of conventional construction to adjust the LCG according to the ship's speed and displacement.
  • This fuel transfer is more readily achieved with gas turbine machinery due to the lighter distillate fuels employed which reduce the need for fuel heating prior to being transferred and is particularly useful in vessels which encounter a variety of speed conditions during normal operation.
  • Fig. 17 demonstrates in general how optimization of trim by moving the longitudinal center of gravity
  • curve B shows that a speed of 20.88 knots the optimum trim occurs when the LCG is about 13 feet forward so that E.H.P. is at about 8750
  • curve C shows that at a speed of 16.59 knots the optimum trim occurs when the L.C.G. is about 17 to 18 feet forward
  • curves D and E show that at respective speeds of 11.69 knots and 8.18 knots the optimum trim occurs when the L.C.G. is about 20 feet forward of midships.
  • optimum trim will occur when the L.C.G. is moved aft of midships to prevent the stern from lifting excessively and thus forcing the bow section down into the water so as to increase resistance.
  • Fig. 18 illustrates how with a vessel of the foregoing type, which has an L/B ratio of about 5.2, optimum trim can result in considerable E.H.P. savings particularly at lower speeds.
  • the dot dash curve designated by the letter E shows the E.H.P. needed for the vessel having a fixed L.C.G. of 13.62 feet aft of midships, as would be optimum for a speed of 40 knots, over a speed range from about 7.5 knots to about 27.50 knots
  • the solid curve designated by the letter F shows the E.H.P. needed when the trim is optimized by moving the L.C.G. forward and aft according to speed and displacement in the manner shown in Fig. 17.
  • Fig. 18 will not be as high as with a ship of the same waterline length and L/B ratio but with lower displacement. Optimization of trim according to changes in vessel speed and displacement is also useful in ensuring optimum immersion of the waterjet pipes which require the point of maximum diameter of their outlet pipes to be level with the waterline when they are started with the ship at a standstill for proper pump priming. There are also several operational advantages of such a trim optimization system, particularly when using shallow water harbors.
  • the hull in accordance with the present invention has a length-to-beam ratio of between about 5 to 1 and 7.5 to l to achieve a ship design having excellent seakeeping and stability while providing high payload carrying capability.
  • Tank tests suggest that this new vessel design will have a correlation, or (1 + x) , factor of less than one.
  • a correlation factor is usually in excess of one for conventional hulls (see curves A and B in Fig. 14), normally a value of 1.06 to 1.11 being recommended. This is added to tank resistance results to approximate the actual resistance in a full scale vessel.
  • a correlation factor of less than one coupled with the hydrodynamic lift is anticipated to result in about a 25% decrease in resistance in the vessel at 45 knots according to my invention as shown by curves C and D in Fig. 14.
  • a ship constructed in accordance with the principles of the present invention will have the following types of characteristics:
  • the endurance is 3500 nautical miles with a 10% reserve margin.
  • Fig. 16 depicts an embodiment where the gas turbines 60 driving one or more generators 61 serve as the primary electrical power source and are carried h.igher in the vessel than in the Fig. 6 embodiment.
  • the electric power generated by the turbines 60 via the generator or generators 61 is used to turn motors 62 which, with or without gearboxes 46, 47, drive the waterjets 26', 27', 28', 29' which are otherwise identical to the waterjets described with respect to Figs. 6, 7 and 15.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)

Abstract

Un bateau (10) comprend une coque (11) à bouchain arrondi, à semi-déplacement ou semi-aplani, qui se caractérise par un faible rapport longueur/largeur maximale (entre 5,0 et 7,5 environ) et utilisant une poussée hydrodynamique. Le fond (15) de la coque (11) s'élève vers la poupe (17) et s'aplatit au niveau de l'arcasse (30). Quatre unités de propulsion à jet d'eau (26, 27, 28, 29) sont montées sur l'arcasse (30), des orifices d'entrée (31) étant disposés sur le fond (15) de la coque juste à l'avant de l'arcasse (30) dans une région soumise à une pression élevée. De l'eau sous haute pression est dirigée jusqu'aux pompes (32) à partir des orifices d'entrée (31). Huit turbines à gaz marines, disposées par paires (36/37, 38/39, 40/41, 42/43) commandent les unités de propulsion à jet d'eau (26, 27, 28, 29) par l'intermédiaire de boîtes d'engrenages (44, 45, 46, 47) et d'arbres de transmission (48, 49, 50, 51).
PCT/US1992/002568 1991-04-01 1992-03-30 Bateau rapide monocoque WO1992017366A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP4510628A JPH06503290A (ja) 1991-04-01 1992-03-30 単胴高速船
KR1019930702962A KR970006351B1 (ko) 1991-04-01 1992-03-30 단선체 쾌속선
NO933510A NO933510D0 (no) 1991-04-01 1993-09-30 Hurtiggaaende skip med enkeltskrog
FI934304A FI934304A0 (fi) 1991-04-01 1993-09-30 Snabbgaoende fartyg med enkelt skrov

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/678,646 US5129343A (en) 1989-10-11 1991-04-01 Monohull fast ship
US678,646 1991-04-01

Publications (1)

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WO1992017366A1 true WO1992017366A1 (fr) 1992-10-15

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PCT/US1992/002568 WO1992017366A1 (fr) 1991-04-01 1992-03-30 Bateau rapide monocoque

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JP (1) JPH06503290A (fr)
KR (1) KR970006351B1 (fr)
AU (1) AU1788292A (fr)
FI (1) FI934304A0 (fr)
WO (1) WO1992017366A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2764264A1 (fr) * 1997-06-05 1998-12-11 Blohm Voss Ag Installation d'entrainement pour des navires, de preference des navires de la marine
US6116180A (en) * 1993-12-16 2000-09-12 Paragon Mann Limited Boat
EP1104739A1 (fr) * 1998-07-15 2001-06-06 Zakrytoe Aktsionernoe Obschestvo" Otdelenie Morskikh sistem okb im. p.o. Sukhogo" Hydroglisseur
ITMI20081240A1 (it) * 2008-07-09 2010-01-10 Ferretti Spa Scafo per imbarcazione con caratteristiche di scafo dislocante e di scafo planante
WO2016042527A1 (fr) * 2014-09-18 2016-03-24 Cantiere Navale Vittoria S.P.A. Coque pour bateaux pour vitesses élevées dans des conditions de mer irrégulières

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2757032A1 (fr) * 2013-01-18 2014-07-23 Technische Universiteit Delft Bateau rapide

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1270134A (en) * 1916-04-05 1918-06-18 Gen Electric Ship propulsion.
US2185431A (en) * 1938-02-03 1940-01-02 Aluminum Co Of America High speed displacement type hull
US2249958A (en) * 1939-08-24 1941-07-22 Inwood John Walter Boat hull
US2342707A (en) * 1941-01-17 1944-02-29 Troyer Nelson Boat
US3826218A (en) * 1972-02-08 1974-07-30 Mannesmann Meer Ag Combination drive for ships
US4079688A (en) * 1976-08-12 1978-03-21 Diry George L Displacement hull
US4276035A (en) * 1976-07-05 1981-06-30 Yamaha Hatsudoki Kabushiki Kaisha Duct systems for water jet propulsion boats
US4843993A (en) * 1986-09-12 1989-07-04 Sulzer Brothers Limited Ship having a stern screw and a method of operating the ship

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1270134A (en) * 1916-04-05 1918-06-18 Gen Electric Ship propulsion.
US2185431A (en) * 1938-02-03 1940-01-02 Aluminum Co Of America High speed displacement type hull
US2249958A (en) * 1939-08-24 1941-07-22 Inwood John Walter Boat hull
US2342707A (en) * 1941-01-17 1944-02-29 Troyer Nelson Boat
US3826218A (en) * 1972-02-08 1974-07-30 Mannesmann Meer Ag Combination drive for ships
US4276035A (en) * 1976-07-05 1981-06-30 Yamaha Hatsudoki Kabushiki Kaisha Duct systems for water jet propulsion boats
US4079688A (en) * 1976-08-12 1978-03-21 Diry George L Displacement hull
US4843993A (en) * 1986-09-12 1989-07-04 Sulzer Brothers Limited Ship having a stern screw and a method of operating the ship

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6116180A (en) * 1993-12-16 2000-09-12 Paragon Mann Limited Boat
FR2764264A1 (fr) * 1997-06-05 1998-12-11 Blohm Voss Ag Installation d'entrainement pour des navires, de preference des navires de la marine
EP1104739A1 (fr) * 1998-07-15 2001-06-06 Zakrytoe Aktsionernoe Obschestvo" Otdelenie Morskikh sistem okb im. p.o. Sukhogo" Hydroglisseur
EP1104739A4 (fr) * 1998-07-15 2002-11-27 Zakrytoe Aktsionernoe Obschest Hydroglisseur
ITMI20081240A1 (it) * 2008-07-09 2010-01-10 Ferretti Spa Scafo per imbarcazione con caratteristiche di scafo dislocante e di scafo planante
WO2016042527A1 (fr) * 2014-09-18 2016-03-24 Cantiere Navale Vittoria S.P.A. Coque pour bateaux pour vitesses élevées dans des conditions de mer irrégulières

Also Published As

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JPH06503290A (ja) 1994-04-14
FI934304A0 (fi) 1993-09-30
AU1788292A (en) 1992-11-02
KR970006351B1 (ko) 1997-04-25

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