WO2017069673A1 - Coque de bateau - Google Patents

Coque de bateau Download PDF

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Publication number
WO2017069673A1
WO2017069673A1 PCT/SE2016/000059 SE2016000059W WO2017069673A1 WO 2017069673 A1 WO2017069673 A1 WO 2017069673A1 SE 2016000059 W SE2016000059 W SE 2016000059W WO 2017069673 A1 WO2017069673 A1 WO 2017069673A1
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WO
WIPO (PCT)
Prior art keywords
aft
hull
planing
strake
angle
Prior art date
Application number
PCT/SE2016/000059
Other languages
English (en)
Inventor
Johan ÅSTRÖM
Original Assignee
Åström Johan
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
Application filed by Åström Johan filed Critical Åström Johan
Publication of WO2017069673A1 publication Critical patent/WO2017069673A1/fr

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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
    • B63B1/16—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces
    • B63B1/18—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type
    • B63B1/20—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type having more than one planing surface
    • 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
    • B63B1/16—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces
    • B63B1/18—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type
    • B63B1/20—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type having more than one planing surface
    • B63B2001/201—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type having more than one planing surface divided by longitudinal chines
    • 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
    • B63B1/16—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces
    • B63B1/18—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type
    • B63B1/20—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type having more than one planing surface
    • B63B2001/202—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving additional lift from hydrodynamic forces of hydroplane type having more than one planing surface divided by transverse steps

Definitions

  • This invention relates to hydroplaning non-ventilated stepped hulls for high-speed multipurpose vessels, eg. SROV, Surveying and Rescue Operational Vessels.
  • Aerodynamic drag affect the performance above 35 knots, but hydrodynamic drag and boat mass affect the performance at all times and can be reduced not only by better streamlining the hull to minimize areas of turbulence and thus wasted energy, but also by reducing the wetted surface area of the hull as well as reducing the weight. Stepped hulls will reduce the drag, as will hydrofoils mounted on the hull, which reduce the drag but only at planing conditions.
  • US 6,666,160 shows a non-ventilated stepped hull having a front part with a first deadrise of 20 degrees, and a second deadrise of 16 degrees, i.e., a twisted front part, and having a aft part with a first deadrise of 20 degrees and a second deadrise of 16 degrees, i.e., a twisted aft part.
  • This hull does not perform well at planing speed but will twist heavily in the water.
  • stepped hulls Another problem with stepped hulls is that they often create a vacuum behind the step. This vacuum increase drag and reduce efficiency.
  • One common way to overcome this problem is to build steps that direct air into the region behind the step. These hulls are referred to as “ventilated” or “aerated” hulls, but then the hull sinks further down in water at planing speed.
  • This invention provides such a boat hull.
  • the hydrodynamic drag has been considerably reduced and it has turned out that the energy consumption, i.e., the gasoline or diesel consumption has been highly reduced.
  • the present hull provides for a more flattened energy consumption curve, i.e., the fuel consumption is only minimally increased from low speed to high speed.
  • the invention provides an unventilated hydroplaning V24 boat hull that has: a forward portion; an aft portion; one midship step separating the forward and aft portions; a forward planing surface that extends transversely immediately forward of the midship step and has a forward angle al of attack being 2.5-4.0 degrees; and an aft planing surface portion that extends transversely and forward of an aft edge of the hull and has an aft angle al of attack being 2.5-4.0 degrees.
  • the forward and aft angles al of attack is 2.5-4.0 degrees, and when the hull is moving at least at a minimum planing speed, the forward and aft planing surfaces constitute two separated wetted surfaces.
  • the interval of angles al of attack depends of the intended working speed of the boat, the faster the lower angle al of attack.
  • each planing surface has a deadrise of 24 degrees. Both the aft and forward portions have the same deadrise angle at the keel line leading edge forward.
  • the longitudinal location of the midship step also affects performance.
  • the midship step is preferably located longitudinally at 0.55-0.65 times L, measured forward from a forward-most point of the aft/transom.
  • L is the length of the hull excluding any protruding constructions at the stem, or at the aft, such as a bow sprit.
  • An important aspect is to provide enough planing surface area compared to the mass of the vessel.
  • One square decimeter at an attack angle of 4.0 degrees has a lifting capacity of 40 kg at 40 knots and 2.5 degrees 20 kg at 40 knots. Therefore a manufacture technology that enhances light hull weight vessels combined with supportive internal bottom stringers that lead out all tensions directly into the strongpoints, aft or bow, is used. If the hull has a total of 2.5 square meters of wet planing surface at 40 knots, then the boat must not have a total mass exceeding 1 400 kg in order to reach 50 knots with 150 hps engine.
  • FIG. 1 is a side view of a stepped boat hull according to the invention
  • FIG. 2 is a bottom view of the boat hull according to the invention
  • FIG. 3 is a perspective bottom view of the boat hull according to the invention.
  • FIG.4 is a detailed part view of a cross-section of a strake across the longitudinal extension of a boat hull according to the invention.
  • FIG. 5 shows a cross-section of the boat hull according to the invention at the aft part of thereof showing stringer layout
  • FIG. 6 shows a cross-section of the boat hull according to the invention at the forward part of thereof showing stringer layout
  • FIG. 7 shows a top view of supportive hull strengthening stringers layout
  • FIG. 8 shows a graph over a comparative study related to fuel consumption as a function of speed.
  • the invention is a stepped, V24-bottomed boat hull for use in high-speed motorboats.
  • FIGS. 1 and 2 show a side and bottom view, respectively, of the hull according to the preferred embodiment of the invention;
  • FIG. 3 is a perspective view from a point below and behind the aft, starboard portion of the hull.
  • the hull may preferably be
  • Deadrise is the angle from horizontal plane to bottom strakes, up to a chine, i.e., the line between actual bottom and the sides of the boat.
  • FIGs. 1-2, 1 denotes a forward part having a deadrise of 24°, also nominated as a V24 in the claims, the forward part 1 being separated from the aft part 2 with a midship step 3.
  • the step 3 is somewhat inclined backwards from the lowest point up to the connection with the aft part 2. This inclination a2 is about 4 to 7°.
  • the actual bottom part 4 of the forward part 1 comprises four strake sections 5 running fore and aft on each side of the keel line 6.
  • the midship step 3 is further as a whole somewhat angled forward forming an apex angle of 160-170° indicated with cx3 equal to 5-10° at the keel line in order to avoid any air ventilation under the aft part 2 bottom.
  • the strake sections 5 are arranged with an angle al of attack of 2.5 to 4.0°.
  • the aft part 2 comprises a forward portion 7 provided with three strake sections 5, whereby this forward portion 7 has no angle of attack.
  • the length of this forward portion is partly depending on the angle of attack, and is partly depending on the total length of the hull.
  • the aft part 2 further an aft portion 8 provided with three strake sections 5, whereby the strake sections 5 of the forward portion 7 and aft portion 8 are fully aligned in the same way as the three strake sections 5 of the aft part 2 is fully aligned with the three outer strake sections 5 of the forward part 1.
  • the aft part 2 may have four strake sections 5 as well.
  • the strake sections 5, whereby one such section is shown in detail in FIG.3, comprises one horizontal wall part 9, an inclined wall part 10 being partly bent and a strake border guide or flange 11 pointing downwardly from the horizontal wall part 9 in the region of a next upper strake section 5.
  • the strake border guide or flange 11 being arranged at the outermost border of the respective strake section 5, is besides pointing downwardly as well somewhat inclined outwardly from the horizontal wall part 9.
  • Such a strake border guide or flange 11 extends downwardly with a length of about 10% of the width of the horizontal wall part 9.
  • the strake border guide 11 must have a minimum height of 5 mm.
  • the strake border guide or flange 11 has an angle a4 of 120 to 135°, to the horizontal wall part 9.
  • the hull according to the invention is thus provided with horizontal lifting strake surfaces, which are longitudinal members or portions running fore and aft on the outside bottom of the hull in order to create lift and stabilize the V24-hull when at speed.
  • the main strake is located at the keel of the bottom. Then there are at least three levels of corresponding lifting strakes on each side and on the front part 1 and aft part 2.
  • the width of the horizontal walls 9 of the strakes 5 is about 100 mm and the projected width of the strakes 5 is about 200 mm on a boat having a width of 2.1 meter and a weight of about 1400 kg.
  • the longitudinal position of the midship step significantly affects the performance of the hull.
  • the outer end of midship step is therefore located longitudinally preferably at 0.55 to 0.65 times the projected water length Lwl, measured from the aftmost part of the stern 12, i.e., the edge of the wet surface at planing.
  • FIGs. 5-7 shows the placement of stringers inside the hull.
  • the stringers 21 and 22 are placed longitudinally above the next outermost strake section 5 on either side of the of the keel line 6.
  • FIG. 7 shows the stringers 21 and 22 meet at the front bow 23.
  • a cross-stringer 24 is placed above the midship step 3 as well as a stringer 25 is placed cross the hull at the transom stern 12.
  • the stringers 21, 22, 24 have the purpose of automatically leading out all tension from hull to bow or aft. Thus all impacts and other loads are absorbed by the different stringers 21, 22, 24.
  • a drag-inducing vortex is created at the outboard edges of each planing surface of a hydroplane hull.
  • This induced drag is usually the greatest drag force on a planing hull.
  • conventional planing hulls have a single, large, planing surface that widens as it goes aft. This large area has a correspondingly large turbulent edge.
  • a traditional, non-stepped planing hull will have a turbulent increased drag area about four times as large as of the hull of the invention. Ventilated hulls have two to three times more disturbed increased drag area due to their increased tip vortex.
  • the hull At a high planing speed, which, for boats having a length of 8.1, at the water line, means a speed in the range of 22-50 knots, the hull has 60% less total wetted area than that of a conventional V-bottom , and up to 50% less total wetted area than that of a so-called air- ventilated stepped hull.
  • the region between the wetted areas (the planing surfaces) is above the water at speed, and in contrasts to conservative straight, V-bottom hulls, in which the wetted area is a single, large, roughly triangular region extending from the stern to midship.
  • the hull according to the invention is self-adjusting, so that no motor trim is needed; this in turn keeps the propeller force horizontal, thus maximizing the driving force.
  • the hull according to the invention When the hull according to the invention is planing, it is “riding" on the two planing, wetted surfaces. As speed increases, the surface area of the wetted surfaces will decrease. The lateral surface, will remain to a large extent constant.
  • the hull according to the invention therefore has two dynamic centers, separated by the step, which each remains in the same position relative to the center of gravity of the hull at any given planing speed.
  • the boat is almost free of "galloping," or pounding, which is an occurrence known to increase drag by around 5% due to the increased wetted area when the nose "dips;” furthermore the up-down "pounding" motion itself creates an energy loss.
  • the portion of the trailing edge of the aft planing surface is located forward, by approximately 9-14% of the length from the stern to the step, relative to the edge portions outboard on either side.
  • the planing surface acts as a "catamaran” in that greater dynamic lift is built up on the outboard portions of the planing surface than near the keel line. This helps prevent chine walking ("swinging").
  • horizontal trimming plans on each side of the engine at the water surface, or at the surface on each side of the propeller in case of inboard motor.
  • the hull has an outboard engine or stern drive engine and a propeller mounted on a transom on the hull. Any propulsion system that can get the hull to a planing speed will benefit from the invention. Nonetheless, by method of illustration; a prototype, of the invention used a Evinrude E-TEC 150 horsepowers (hps) (2-stroke), gasoline-fueled, outboard engine driving a 14x26-inch (diameter ⁇ pitch) stainless propeller and raised 50 mm. The prototype boat was 8.1 x 2.1 (waterline length) meter, and tests were conducted with two adults, 2 x 80 kg and 40 liters of gasoline. The total weight of boat, engine, fuel, equipment and persons was 1480 kg.
  • the invention compared the performance of the hull, here called FFWD, according to the preferred embodiment of the invention with several other conventional hulls under essentially identical sea states and with the same two-person load.
  • the specifications of the embodiment of the invention used in the test are stated above with reference to the working prototype.
  • the results are summarized in Table 1 below. In Table 1 it is shown, for each tested hull, the make and model, length ⁇ width in meters (m), the mass (kg), the motor effect (in horsepower), the maximum achieved speed Vmax (knots).
  • a comparative study concerning the fuel economy has been made wherein data concerning different boats and motors have been compared with a fuel economy related to the present hull.
  • Data have been obtained from the Swedish Boat Magazine - VI BATAGARE - when it comes to other boats than the present one,l) herein called FFWD provided with a 150 hps outboard Evinrude engine.
  • the other hulls teste were 2) Anytec 750 hps having a 300 hps engine, 3) Buster Super Magnum having a 300 hps Hyundai engine, 4) Yamarin Cros 75BR having a 300 hps engine and 5) an XO 240RS Open having a 250 hps engine.
  • the hulls tested are conventional aluminium hulls. All gasoline fed.
  • the fuel consumption is about 1.8 litres per nautic mile at a speed of about 43 knots per hour for the boats 2) to 5) compared to 1.8 litres per nautic mile at a speed of 61 knots per hour for the present boat 1). Or, 0.9 litre per nautic mile at a speed of 45 knots per hour for the boat 1). It means that the present hull only needs less than 50% of fuel compared to that of a conventional hull.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Underground Or Underwater Handling Of Building Materials (AREA)
  • Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
  • Hydraulic Turbines (AREA)

Abstract

La présente invention concerne une coque de bateau d'hydroplanage à emplanture, sans air qui comporte une emplanture de navire centrale. Deux surfaces de planage mouillées séparées sont établies ainsi : - une surface avant directement à l'avant de l'emplanture et une surface arrière directement à l'avant d'un bord arrière de la coque. Les angles d'attaque de chaque surface de planage sont de 2,5 à 4,5 degrés, et sont égaux. L'emplanture centrale est située longitudinalement à 0,55 à 0,65 fois la longueur de ligne d'eau projetée de la coque, mesurée vers l'arrière depuis un bord le plus à l'arrière d'une surface de planage arrière. La surface à emplanture comporte au moins trois niveaux de virures de levage horizontales mesurés longitudinalement depuis un point le plus à l'avant vers l'arrière.
PCT/SE2016/000059 2015-10-23 2016-10-20 Coque de bateau WO2017069673A1 (fr)

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Application Number Priority Date Filing Date Title
SE1500423A SE540477C2 (en) 2015-10-23 2015-10-23 Boat hull
SE1500423-7 2015-10-23

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108791694A (zh) * 2018-06-07 2018-11-13 中国船舶科学研究中心（中国船舶重工集团公司第七0二研究所） 一种大断阶高速滑行艇艇型

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2039586A (en) * 1935-05-23 1936-05-05 Eddy Planing boat
US3568617A (en) * 1969-03-11 1971-03-09 John V Yost Step-ramp v-hull
US5191853A (en) * 1991-05-24 1993-03-09 Adler Alan John Stepped hydroplane hull
US5456202A (en) * 1990-10-12 1995-10-10 Schoell; Harry L. Planing boat hull
US5588389A (en) * 1995-03-30 1996-12-31 Carter, Jr.; Jay Dual lift boat hull
US6425341B1 (en) * 1998-08-28 2002-07-30 Neville John Devin Boat hull
US6666160B1 (en) * 2000-03-15 2003-12-23 Oerneblad Sten High aspect dynamic lift boat hull
US20050160960A1 (en) * 2004-01-23 2005-07-28 Carmelo Batista Levitation and stabilizing hull system
DE602004009467T2 (de) * 2003-10-30 2008-07-24 Chantiers Beneteau S.A. Schiffsrumpf
US20100313808A1 (en) * 2009-06-16 2010-12-16 Safe Boats International L.L.C. Watercraft with stepped hull and outboard fins
SE537875C2 (sv) * 2013-06-11 2015-11-10 Petestep Ab Vattenfarkost med planande skrov

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2039586A (en) * 1935-05-23 1936-05-05 Eddy Planing boat
US3568617A (en) * 1969-03-11 1971-03-09 John V Yost Step-ramp v-hull
US5456202A (en) * 1990-10-12 1995-10-10 Schoell; Harry L. Planing boat hull
US5191853A (en) * 1991-05-24 1993-03-09 Adler Alan John Stepped hydroplane hull
US5588389A (en) * 1995-03-30 1996-12-31 Carter, Jr.; Jay Dual lift boat hull
US6425341B1 (en) * 1998-08-28 2002-07-30 Neville John Devin Boat hull
US6666160B1 (en) * 2000-03-15 2003-12-23 Oerneblad Sten High aspect dynamic lift boat hull
DE602004009467T2 (de) * 2003-10-30 2008-07-24 Chantiers Beneteau S.A. Schiffsrumpf
US20050160960A1 (en) * 2004-01-23 2005-07-28 Carmelo Batista Levitation and stabilizing hull system
US20100313808A1 (en) * 2009-06-16 2010-12-16 Safe Boats International L.L.C. Watercraft with stepped hull and outboard fins
SE537875C2 (sv) * 2013-06-11 2015-11-10 Petestep Ab Vattenfarkost med planande skrov

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108791694A (zh) * 2018-06-07 2018-11-13 中国船舶科学研究中心（中国船舶重工集团公司第七0二研究所） 一种大断阶高速滑行艇艇型
CN108791694B (zh) * 2018-06-07 2020-04-03 中国船舶科学研究中心（中国船舶重工集团公司第七0二研究所） 一种大断阶高速滑行艇艇型

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Publication number Publication date
SE540477C2 (en) 2018-09-25
SE1500423A1 (en) 2017-04-24

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