Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
  • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H1/00—Propulsive elements directly acting on water
  • B63H1/02—Propulsive elements directly acting on water of rotary type
  • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
  • B63H1/14—Propellers
  • B63H1/28—Other means for improving propeller efficiency
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
  • B63H25/06—Steering by rudders
  • B63H25/38—Rudders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
  • B63H25/06—Steering by rudders
  • B63H25/38—Rudders
  • B63H25/381—Rudders with flaps

Definitions

• the invention relates to a propulsion and steering unit for a vessel comprising an integrated propeller/torpedo/rudder arrangement, wherein the torpedo is a part of a rudder horn fixedly mounted in a ship, and where the maximum diameter ofthe torpedo is greater than the diameter ofthe propeller hub.
• the main objective of the present invention which relates to an integrated system consisting of rudder, torpedo and propeller, is to improve propulsion efficiency and manoeuvring characteristics in relation to ships having conventional systems with separate rudder and propeller.
• British Patent Application No. 762445 makes known different types of the traditional Costa bulb, which have greater maximum diameter than the propeller hub, and which are arranged on the rudder behind the propeller. In the case of the structures taught here, the water flow between the hub and the front edge of the bulb will take place in such manner that the resistance of the bulb will increase.
• the solutions described are designed according to the principle that contraction of the propeller slip stream is wholly or partly eliminated by locating the front edge of the bulb close to the after end of the propeller blades.
• British Patent Publication No. 385607 makes know ⁇ i bodies mounted behind the propeller hub in such manner that in the case of fixed propellers they represent an extension ofthe propeller hub. Forward of these propeller hub extensions are openings to receive the nut at the rear ofthe fixed propeller.
• the diameter of these propeller hub extensions is not greater than that ofthe hub and therefore they will not reduce the contraction ofthe propeller slip stream.
• the main objective of this known solution is to avoid energy loss caused by cavitation behind the hub.
• an integrated propeller/to ⁇ edo/rudder arrangement wherein the to ⁇ edo is a part of a rudder horn fixedly mounted in the ship, and where the largest diameter ofthe to ⁇ edo is greater than the diameter ofthe propeller hub, what characterises the invention being that the propeller hub, together with the to ⁇ edo, forms a uniform streamlined profile, the propeller hub being designed to have an increasing diameter in the region from the front edge and aftward.
• a streamlined body termed a to ⁇ edo, which has a greater maximum diameter than the propeller hub.
• the propeller hub and to ⁇ edo are designed so that together they form an optimised streamlined profile, i.e., a continuous profile from the front edge ofthe propeller hub to the after end ofthe to ⁇ edo, broken only by a narrow gap.
• the to ⁇ edo is mounted fixedly relative to the ship in that it is rigidly secured to the rudder horn.
• the roots ofthe blades are inco ⁇ orated into the streamlined profile.
• one or both surfaces in the rotation gap are coated with a tear-proof bearing material.
• the after part ofthe to ⁇ edo ends behind the axis of the rudder stock, and cuts into the rudder blade, which has a notch corresponding to the outline ofthe to ⁇ edo. A small clearing is included in this notch so that the rudder blade can swing unimpeded whilst the pressure leakage through the gap is minimal on small rudder deflections.
• the whole system consisting of propeller blades, propeller hub, to ⁇ edo, rudder horn, rudder blade, optional flaps and optional fins is integrated and optimised with a view to optimal propulsion efficiency and manoeuvring characteristics.
• the forward part ofthe bulb profiles is located behind the propeller centre.
• the forward part ofthe bulbs is designed so that the form resistance ofthe bulb increases and/or is located on a moveable rudder so that the bulb's resistance, and thus the necessary engine output, increase on the small rudder deflections which are necessary to keep the vessel on the planned course.
• the propulsion and steering unit according to the present invention is designed so that the to ⁇ edo and propeller hub form an uninterrupted streamlined profile. This is done to eliminate more efficiently contraction ofthe propeller slip stream, and also to recover more ofthe energy loss which is caused by vortex shedding and cavitation behind the propeller hub.
• the propeller hub together with the to ⁇ edo according to the present invention, constitutes a uniform streamlined profile, it is also possible to increase propulsion efficiency by increasing the load along the propeller blades.
• the transition between the propeller hub, to ⁇ edo and rudder has been designed such that it is not possible to achieve any appreciable recovery of this increased energy loss caused by more powerful quarter- hollow vortices and shedding behind the propeller hub.
• Radial fins mounted on the surface ofthe to ⁇ edo can, in certain cases, be used to recover more ofthe rotation energy in the propeller slip stream.
• Tests with models have shown that in relation to the known conventional arrangements with rudder bulbs, the new integrated system according to the invention provides a considerably higher degree of propulsion efficiency and thus reduced necessary engine output. The desired effects of using a continuous streamlined profile and to ⁇ edo/rudder combination are thus achieved.
• Tests carried out with models show that in contrast to the previously known bulbs this integrated system gives increased gain on increasing ship speed.
• the length/breadth ratio of the hull has been steadily reduced. This has resulted in a number of vessels having poor straight line and course stability.
• the invention with the fixedly mounted to ⁇ edo in the propeller slip stream together with the rudder horn, will impart to the vessels improved straight line and course stability. In particular in the case of vessels which operate on long runs, the invention will reduce necessary rudder use to maintain course and thus reduce fuel consumption further.
• the integrated system according to the invention will moreover eliminate hub vortices/shedding behind the hub, and will thus contribute towards a considerable reduction in propeller-induced subsea noise.
• Fig. l is a lateral view of an example of the invention.
• Fig. 2 shows an example ofthe invention where an unbalanced rudder is used
• Fig. 3 is a section through the to ⁇ edo arrangement in Fig. 1 ;
• Fig. 4 shows two rings which form a part ofthe to ⁇ edo
• Fig. 5 is a perspective view of an embodiment ofthe invention.
• Fig. 1 the main components can be seen: a variable pitch propeller 1 , a to ⁇ edo 2, rudder horn with rudder case 3, and a semi-balanced rudder 4.
• the propeller and rudder are positioned as on traditional ships.
• the propeller 1 is shown as a variable pitch propeller, but may also have fixed pitch.
• the illustrated outer contour 5 ofthe propeller hub 6 may either be cast in a single piece with the hub or be a screwed-on or shrunk-on adapter ring having a correct outer contour, adapted to an existing hub.
• the to ⁇ edo 2 which has its greatest diameter approximately forward ofthe rudder horn 3, is located in the extension ofthe propeller hub 6 and is flanged (screwed) 7 into place on the rudder horn 3.
• the horn bearing 8 is built into the after end ofthe to ⁇ edo 2.
• the rudder 4 has a notch 9 which accommodates the after end ofthe to ⁇ edo 2.
• Fig. 2 shows an example of the invention where an unbalanced rudder 10 is used.
• the rudder horn 1 1 here is extended down to the lower edge ofthe rudder blade 10, and the hom bearing 12 is located at the very bottom.
• the rudder hom 11 is split by a horizontal flange 13 above the to ⁇ edo 14 (for dismounting purposes) and the lower part of the rudder hom is integrated with the to ⁇ edo.
• the rudder blade can be equipped with flaps, if so desired.
• Fig. 3 shows a section through the to ⁇ edo arrangement in Fig. 1.
• the propeller hub 6 has a conventional outer contour which has been modified and adapted to the streamlined shape ofthe to ⁇ edo 2 by means of a screwed-on transition ring 5, the after end of which forms one side of the rotation gap 15.
• the rotation gap 15, as shown in the detailed section, is designed to be conical with the greatest diameter facing abaft. This is to improve the flow conditions over the gap, and also to reduce the effect of any axial deviations between the propeller and to ⁇ edo.
• the to ⁇ edo 2 is divided into three parts, a fixed after part 16 which is designed to have a flange 17 on the upper side for attachment to the rudder hom 3 by means of flange connection 7, and two detachable concentric rings 18, 19 which are held in place by a dog bolt 20. Forward ofthe foremost ring 19 there is a shoulder tuming upon which a ring 21 of tear-resistant material is placed. This ring, as is apparent from the detailed section, is adapted to the rotation gap 15.
• the hom bearing boss 22 in the lower hom bearing 8 (Fig. 1) is suspended in a bracket 23 which is structurally integrated into the to ⁇ edo 2, i.e., in the to ⁇ edo's fixed after part 16.
• the to ⁇ edo may to advantage include two rings 18, 19 which are designed to have eccentrically displaced end surfaces, as is shown in Fig. 4, where the eccentricities are indicated with the letter e.
• the design ofthe to ⁇ edo has been modified relative to that shown in Figs.
• the part ofthe to ⁇ edo 2 which is in front ofthe rudder hom 3 consists of two semi ⁇ cylindrical cover plates 25, 26 (shown drawn apart from one another), whose side edges are flanged so that they can be screwed together in a vertical plane running through the axis ofthe propulsion system, and the after end 27 of which (only shown for one cover plate 26) is flanged so that it can be screwed to a corresponding flange in the front edge ofthe after part ofthe to ⁇ edo, and the front edge of which is designed to be the after part ofthe rotation gap 15 and forms one ofthe defining surfaces thereof.
• rudder ho and the rudder case 3 have the same extemal profile as the rudder blade 4, and that the rudder horn/rudder case 3 is constmcted with a constant cross-section through the skin plate 28 ofthe ship and is secured (welded) thereto and also to the deck 29 in the ship's steering engine room and to vertical braces 30.
• the to ⁇ edo may have reaction fins.
• reaction fins are known, for example, from NO 154262.
• the invention provides an integrated system for the propulsion and steering of a ship.
• a to ⁇ edo is used which is suspended in the rudder hom and cannot be swung relative to the ship.
• the outer form ofthe to ⁇ edo is such that, together with the specially designed propeller hub, it forms an optimised streamlined rotary body. All components in the system interact hydrodynamically and are optimised as a combined unit with a view to propulsion efficiency and manoeuvrability.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Toys (AREA)
• Mixers Of The Rotary Stirring Type (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Bridges Or Land Bridges (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19898613

Family Applications (1)

Country Status (8)

Cited By (14)

Families Citing this family (1)

Citations (3)

• 1995
  • 1995-09-29 NO NO953871A patent/NO302515B1/no not_active IP Right Cessation
• 1996
  • 1996-09-27 PL PL96325870A patent/PL181883B1/pl not_active IP Right Cessation
  • 1996-09-27 WO PCT/NO1996/000231 patent/WO1997011878A1/en active IP Right Grant
  • 1996-09-27 DE DE69619388T patent/DE69619388T2/de not_active Expired - Lifetime
  • 1996-09-27 AU AU72306/96A patent/AU7230696A/en not_active Abandoned
  • 1996-09-27 EP EP96933671A patent/EP0852551B1/en not_active Expired - Lifetime
  • 1996-09-27 DK DK96933671T patent/DK0852551T3/da active
  • 1996-09-27 ES ES96933671T patent/ES2170873T3/es not_active Expired - Lifetime

Patent Citations (3)

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