EP0033322B1 - A rudder arrangement for boats and ships - Google Patents

A rudder arrangement for boats and ships Download PDF

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Publication number
EP0033322B1
EP0033322B1 EP80901451A EP80901451A EP0033322B1 EP 0033322 B1 EP0033322 B1 EP 0033322B1 EP 80901451 A EP80901451 A EP 80901451A EP 80901451 A EP80901451 A EP 80901451A EP 0033322 B1 EP0033322 B1 EP 0033322B1
Authority
EP
European Patent Office
Prior art keywords
rudder
tunnel
boats
boat
plane
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
EP80901451A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0033322A1 (en
Inventor
Odd Braa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0033322A1 publication Critical patent/EP0033322A1/en
Application granted granted Critical
Publication of EP0033322B1 publication Critical patent/EP0033322B1/en
Expired legal-status Critical Current

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Classifications

    • 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

Definitions

  • the present invention relates to a rudder arrangement for boats and ships according to the preamble of claim 1.
  • the effect of a boat rudder is to deflect the flow of water relative to the longitudinal direction of the boat, whether this flow results from the speed of the boat or from water which has been set in motion by the screw.
  • the propeller flow is far from laminar, and it therefore has a relatively bad effect on the steering of the boat. Therefore, a boat travelling at slow speed will have poorer steering than the same boat travelling at higher speeds.
  • the screw will reduce the steering properties of the boat. This is particularly true when reversing, because the laminar flow of water which moves along the hull of the boat will be broken up by the propeller, which has poor screw properties when reversing, the blades of a propeller being constructed first and foremost with forward propulsion in mind. On boats which have poor steering capabilities in reverse, therefore, one must often set the boat in motion backwards and then cut out the propeller before the rudder will have any steering effect.
  • a rudder arrangement of the type defined in the preamble of claim 1 is previously known from DE-C-345 785.
  • This known arrangement is primarily adapted for controlling the speed of and enabling backwards movement of a vessel which cannot be caused to move astern by reversing the rotational direction of its propeller. It comprises a tunnel formed by two tunnel sections which are rotatable both individually and in unison about a substantially vertical axis and which require a complicated control device. The forward portions of the tunnel sections are normally located like a shield outside the propeller blades and adversely interfere with the action of the propeller.
  • a modification on a rudder is known from NO-A-59 795, in which plates that are parallel with the rudder surface are provided on each side of the rudder, the leading edge of the plates projecting forward of the middle leading edge of the rudder.
  • the primary object of this modification is to balance the rudder, in that one thereby obtains steering surfaces which lie in front of the rudder shaft.
  • a similar modification is known from US-A-3 181 492.
  • the object of the present invention is to provide a rudder arrangement for boats and ships which improves the steering properties of the boat both when reversing and during forward propulsion.
  • the rudder configuration according to the present invention provides quite superior steering properties, especially when reversing. This is very important, as reversing with boats having a pointed bottom configuration, such as the Norwegian "snekke" fishing boat, has always been problematic. With a rudder having the configuration defined above, such a boat will answer the helm equally well in both directions, while it would normally answer the helm only in the direction of rotation for the propeller. The steering properties of the boat will also be improved in the forward direction, especially when moving forward at very slow speeds.
  • a practical embodiment of the invention is characterized in that the tongues constitute approximately one-half of the total length of the tunnel in the longitudinal direction. Conveniently, the ratio of the total length of the tunnel to the diameter of the tunnel lies between 3:4 and 3:6.
  • a circular, tunnel- or channel- shaped rudder 1 is provided between the stern 2 of the boat and a lower rudder support 3.
  • the rearwardly-projecting support 3 is the most common construction on small boats, but one also finds types of boats in which this support is not present, in which case the rudder is supported solely by the rudder post 4.
  • the boat illustrated in this example is driven by a three-blade screw with reversible directions of rotation.
  • the rudder shaft 4 is attached to the channel 1 forward of the middle of the total length L of the channel.
  • Two V-shaped notches have been cut into the tunnel at its rearward end, the tip of each V lying in the central vertical plane through the channel 1. In this manner, respective arch-shaped tongues 7, 8 are formed on each side of said plane, the total length a of the tongues in the longitudinal direction of the channel being approximately equal to one-half the total length L of the channel.
  • Figure 3 shows an embodiment which is well suited for rebuilding the rudder of a boat which is already equipped with a conventional plate rudder 9, placed between the stern 2 of the boat and the lower support 3.
  • the boat is driven by a three-blade screw 5 with reversible directions of rotation.
  • the rudder is rotated by means of a rudder shaft 4, which is placed a distance behind the leading edge of the rudder plate 9 in order to obtain a certain balancing effect.
  • Attached to both flat sides of the rudder 9 are arched guide plates 11 and 12.
  • the curvature of the plates is in accordance with a circular line in the crosswise direction of the boat, such that the two plates 11, 12 together form a circular-shaped channel.
  • the lateral marginal edges 13 of the plates 11, 12 are parallel with one another and with the rudder surface on the plate rudder 9.
  • the plates 11 and 12 are attached at their upper and lower edges 14 and 15 to the respective upper and lower edges of the rudder surface.
  • the forward edge 16 on the plates 11, 12 is disposed somewhat astern of the rudder shaft 4.
  • the plates 11, 12 have a curved rearward edge 16, such that the outer marginal edges 13 of the plate project somewhat astern of the plate parts, which are attached to the rudder at 14 and 15. In this way, tongues or overhangs 17 are formed.
  • the diameter of the channel which is formed by the two plates 11 and 12 is larger than the screw diameter of the propeller 5.
  • the length a of the overhang 17 is approximately equal to the remaining length b of the total length L (see Figure 5), i.e., the length a of the overhang 17 is approximately equal to one-half of the total length of the plates 11 or 12.
  • a rudder modification in accordance with the exemplified embodiments was tested on a small fishing boat which had extremely poor steering properties, especially when reversing. At slow speeds, this "snekke" boat did not answer the helm at all in one direction during a reversing operation. The boat's berth was situated such that the sea and wind often blew toward land, and it often happened that the owner could not take his boat out for the sole reason that it was not sufficiently manoeverable, as it was impossible to steer the boat in reverse. After the modification according to the invention was installed, the owner claimed that the boat was as easy to steer as an automobile, and that it answered the helm when driven in reverse both at slow speeds and at full speed. In addition, the turn radius during forward propulsion had also become substantially smaller.
  • Another effect of the modification according to the invention is that it also prevents or greatly reduces the downward drag on the stern end of boats of this type. This is a common phenomenon, and it reduces speed or increases fuel consumption rather significantly. In order to prevent this, some boats have a hull built with an expensive support plane or support-fins in the region of the screw. Such hull modifications can be rendered unnecessary with the use of the invention, and the price of the hull correspondingly reduced.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Traffic Control Systems (AREA)
  • Toys (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
EP80901451A 1979-08-10 1981-03-24 A rudder arrangement for boats and ships Expired EP0033322B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NO792611 1979-08-10
NO792611A NO144737C (no) 1979-08-10 1979-08-10 Anordning ved ror for baater og skip.
NO800746 1980-03-14
NO800746 1980-03-14

Publications (2)

Publication Number Publication Date
EP0033322A1 EP0033322A1 (en) 1981-08-12
EP0033322B1 true EP0033322B1 (en) 1984-12-12

Family

ID=26647678

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80901451A Expired EP0033322B1 (en) 1979-08-10 1981-03-24 A rudder arrangement for boats and ships

Country Status (7)

Country Link
EP (1) EP0033322B1 (no)
JP (1) JPS56501005A (no)
DE (1) DE3069796D1 (no)
DK (1) DK160481A (no)
FI (1) FI63904C (no)
NO (1) NO144737C (no)
WO (1) WO1981000389A1 (no)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06219391A (ja) * 1993-01-25 1994-08-09 Tokyo Eng:Kk 船舶等の舵装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE345785C (de) * 1914-02-07 1921-12-17 Gordon Henry Fraser Vorrichtung zur Regelung der Geschwindigkeit und der Fahrtrichtung von Schiffen, Booten o. dgl.
GB251314A (en) * 1924-10-30 1926-04-30 Kitchen S Reversing Rudder Com Improvements relating to reversing rudders
US2328041A (en) * 1942-09-11 1943-08-31 Charles M Wellons Steering device for boats
US3181492A (en) * 1962-08-27 1965-05-04 Leiter W Hockett Rudder for marine vessels

Also Published As

Publication number Publication date
FI63904B (fi) 1983-05-31
EP0033322A1 (en) 1981-08-12
JPS56501005A (no) 1981-07-23
WO1981000389A1 (en) 1981-02-19
NO144737B (no) 1981-07-20
FI802492A (fi) 1981-02-11
NO144737C (no) 1981-10-28
NO792611L (no) 1981-02-11
FI63904C (fi) 1983-09-12
DE3069796D1 (en) 1985-01-24
DK160481A (da) 1981-04-09

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