US3911850A - Device for displacing the engagement point of a hawser - Google Patents

Abstract

A device for displacing the engagement point of a hawser extending from the stern of a towing ship includes a rocker arm pivotally mounted on an axis in the plane of the longitudinal axis of the vessel and positioned sternwardly of a pivot point at which the hawser extends from the ship. There is a hawser opening on the end of the arm and the arm is pivotable in a vertical plane between abutments located on both sides of the longitudinal plane.

Description

1 14-253 OR 3 9 l 1 850 SR 1 1 z a m a United States Patent [1 1 [111 3,911,850

Baer et a1. Oct. 14, 1975 [54] DEVICE FOR DISPLACING THE 2,972,325 2/1961 Beltmann et al 114/235 ws ENGAGEIVIENT POINT OF A HAWSER Inventors: Wolfgang Baer; Ulrich Sturmhiifel, both of I-Ieidenheim (Brenz); Karl Blickle, Bolheim, all of Germany J. M. Voith, GmbH, I-Ieidenheim (Brenz), Germany Filed: June 6, 1974 Appl. No.: 476,947

Assignee:

Foreign Application Priority Data June 9, 1973 Germany 2329633 US. Cl 114/235 A Int. Cl. B63B 21/56 Field of Search 114/235 R, 235 B, 235 WS,

References Cited UNITED STATES PATENTS 7/1934 Taylor 114/236 FOREIGN PATENTS OR APPLICATIONS 1,272,302 8/1961 France 114/235 R 573,091 3/1933 Germany l14/235 R Primary ExaminerTrygve M. Blix Assistant Examiner-Gregory W. OConnor Attorney, Agent, or FirmEdmund M. Jaskiewicz ABSIRACT A device for displacing the engagement point of a hawser extending from the stern of a towing ship includes a rocker arm pivotally mounted on an axis in the plane of the longitudinal axis of the vessel and positioned stemwardly of a pivot point at which the hawser extends from the ship. There is a hawser opening on the end of the arm and the arm is pivotable in a vertical plane between abutments located on both sides of the longitudinal plane.

6 Claims, 10 Drawing Figures US. Patent Oct. 14,1975 Sheetlof4 3,911,850

U.S. Patent Oct. 14, 1975 Sheet 2 of4 3,911,850

U.S. Patent Oct. 14, 1975 Sheet 4 of 4 3,911,850

Fig.9

DEVICE FOR DISPLACING THE ENGAGEIVIENT POINT OF A HAWSER The present invention relates to a ship towing arrangement using a hawser extending from the stern of a ship, more particularly, to displacing the point of engagement of the hawser with a portion of the ship.

A ship which is particularly constructed for towing of a ship or the like, such as a tug boat, is generally provided with a hawser extending sternwardly of the towing ship and pivotally attached to the ship. One or more abutments are positioned sternwardly of the hawser pivotal connection on either side of the plane of the longitudinal axis of the ship to guide the hawser between the abutments. The point at which the two hawser engages a portion of the ship has a significant effect on the performance and operation of the towing ship during the towing operation. The safety of the towing ship with respect to exceeding its transverse stability because of forces exerted by the hawser in a transverse direction similarly substantially depends on the position of the point of engagement of the hawser.

In a tug boat which is driven and steered from the how, the point of engagement for the towing hawser is located in approximately the rear third of the ship. The further to the rear that the point of engagement is located the more stable will be the play of forces between the propeller thrust and the hawser thrust and also there will be greater safety against capsizing when the hawser extends transversely.

When a tug boat is to be used primarily for long distance towing it is undesirable to locate the point of engagement near the stern since such a location would require excessive power for steering of a train of barges toned by the tub boat. Consequently, a point of engagement position which is somewhat less stabilizing but which requires small steering forces is more economical in the case of long distance towing. On the other hand, when the tub boat is employed in a port for short range operation such as docking or brakingthen it is desirable to provide as much safety as possible against capsizing and a point of engagement is desirable which is strongly stabilizing. In practice this means that the point of engagement should be located approximately on the first section of the ships hull which is approximately one tenth of the length of the ship. In the case of long distance operations the optimal point of engagement is located approximately on the body sec tions 2V2-3 which correspond approximately to onefourth of the ships length.

A proposal for improving the operations of a tug in both port and long distance operations has been advanced in the periodical Schiff und Hafen (Ship and Port), volume 8, August, 1971, pages 649-652. This proposal included mounting a towing hook in the customary location on section three of the hull. A pair of bollards are positioned sternwardly of the pivot to act as lateral abutments for pivoting movement of the hawser. When the tub boat is traveling in the forward direction during a long distance towing operation the hawser is passed freely over the bollards by means of a bar. When the tub boat is to be used in port, an operator opens a flap on a bollard and the hawser is placed between the bollards. The bollards will then define the lateral movement of the hawser. Should the hawser become oriented in the transverse direction, the point of engagement of the hawser is displaced from the pivot sternwardly with the increasing lateral angle of the hawser until at a hawser angle of the hawser is located practically in the plane of the limiting bollards. A stabilizing engagement point or hook position is thus obtained.

This arrangement has the disadvantage in that the displacement of the point' of engagement of the hawser is dependant upon an operator. Should the operator for some reason fail to position the hawser between the bollards, there is then a considerable risk of capsizing during operations in a'port.

It has also been proposed to pass the hawser under a towing bitt which is provided with wider lateral abutments. However, this arrangement has the disadvantage of producing undesirable friction from the hawser rubbing on the upper spar of the bollards and thus it is not possible to guarantee the pivoting of the hawser in this particular angular range.

It is therefore the principal object of the present invention to provide a novel and improved device for displacing the point of engagement of a hawser extending from the stern of a towing ship.

It is another object of the present invention to provide a device which reliably and consistently displaces the point of engagement of the hawser while at the same time protects the hawser from undue wear.

According to one aspect of the present invention a device for displacing the point of engagement of a hawser with a portion of a ship wherein a hawser extends from the stern of a towing ship may comprise means defining a point on the ship at which a hawser pivotally extends therefrom. Stemwardly of the pivot point there is provided means to define a pivot axis in the plane of the longitudinal axis of the ship. A rocker arm is pivotally mounted on the pivot axis and has a hawser opening on its end. Abutment means are provided on both sides of the axis plane so as to be engagable by the rocker arm to limit the range of pivoting.

In a modification, abutment means are mounted sternwardly of the pivot point on both sides of the plane passing through the longitudinal axis of the ship. An intermediate element which may be a link or a chain is pivotally mounted at the pivot point and pivots between the abutment means. A tow hook is pivotally mounted on the end of an intermediate element. A transverse member which may be curved interconnects the abutment means to guide the pivoting movement of the intermediate member. Roller means may be provided on the intermediate element to facilitate and guide the movement .of the intermediate element with respect to the transverse member.

The hawser is thus protected by being guided through a hawser opening which avoids to a considerable extent any rubbing of the hawser. In addition, the displacement of the point of engagement of the hawser is performed automatically in accordance with the type of use. For long distance operations, the hawser is freely moveable and the point of engagement is situated in the optimal position for such a towing operation. However, in the event the hawser should exceed a certain angle it immediately contacts the abutments which has the effect of displacing the point of engagement of the hawser sternwardly. The result is to increase the safety conditions of the towing vessel with respect to capsizing.

Other objects and advantages of the present invention will be apparent on reference to the accompanying description when taken in conjunction with the following drawings, which are exemplary, wherein;

FIG. 1 is a top plan view of a displacing device in accordance with the present invention;

FIG. 2 is a front elevational view of the device of FIG. 1;

FIGS. 3 and 4- show a modification comprising a displacable hawser opening with FIG. 3 being a front elevational view with FIG. 4 being a vertical sectional view taken along the line 4l 4 of FIG. 3;

FIG. 5 is a perspective view looking rearwardly at a further modification of a displacing device according to the present invention;

FIGS. 6, 7 and 8 are vertical sectional views through the end of the intermediate element and the transverse member showing profiles thereof and the mounting of rollers for guiding the intermediate member upon the transverse member;

FIG. 9 is a top plan view of a modification of a displacing device wherein the transverse member is provided with a variable radius; and

FIG. 10 is a side elevational view of the device of FIG. 9.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views a specific embodiment and modifications of the present invention will be described in detail.

In FIGS. l and 2 there is shown a device for displacing the point of engagement of a hawser comprising a pivot I with a towing hook 2 located approximately at section 2 /2 of a towing ship. Located sternwardly of the pivot point 1 and approximately on section 1 of the hull there is mounted a hawser opening frame 3 disposed on the outer or free end of a rocker arm 4. It is mounted between bearings 5 and 6 for pivotal movement about an axis which is in the plane of the longitudinal plane of the ship. The bearings 5 and 6 are mounted on the deck of the ship so that the rocker arm is pivotable therefrom. Abutments '7 and 8 are positioned at an angle of about to the longitudinal axis of the ship and are engagable by the rocker arm. A hawser 9 is led through an opening I0 in the hawser opening frame 3.

With this structure, the hawser is freely moveable for long distance towing which occurs when the tow ship is traveling in substantially a straight line. The point of engagement of the hawser is located at pivot I. In the event the direction of the hawser should exceed an angle of 20 in the case of transverse thrust the hawser opening frame 3 will contact one of the abutments 7 or 8 as a result of which the point of engagement of the hawser will be displaced sternwardly from pivot 1 as the transverse position of the hawser increases until the hawser opening frame 3 contacts abutment 7 or 8.

In order to avoid hard or excessive impacts or shocks against the abutments a fluid pressure lifting cylinder 11 may be pivotally connected to the rocker arm 4 so as to function as a shock absorber. The lifting cylinder 3 is provided with a pressure equalization line 32 and a control valve 33. The cylinder llll may also be connected to a source of pressure through a line 34 to enable the desired portion of line 32 to be supplied with fluid under pressure by suitable control of valve 33. As a result, pressure will be applied to the desire piston surface of the piston with the cylinder llI. Also, the cylinder II can function to retain the rocker arm 4 firmly in an intermediate position so that the hawser is bent at a smaller pivoting angle.

The pivot axis of the rocker arm 4 of fulcrum is located below the hawser opening frame 3 and preferably perpendicularly below the frame 3. This results in locating the point of engagement of the hawser at a lower level during transverse movement of the hawser and this improves considerably the stability conditions.

By setting the cylinder in an intermediate position the displacement of the point of engagement of the hawser will occur at a smaller angle with respect to the longitudinal axis of the ship that would be the case when the rocker arm is stopped by one of the abutments 7 or 8. Thus, when the piston of the cylinder is in its upper or lower end position, the hawser will be bent during further transverse movement thereof and the point of engagement will be displaced sternwardly.

The embodiments and modifications of FIGS. 1-4- provide for the possibility of towing by means of a hook or by means of a winch mounted on the towing vessel. This is particularly shown in FIG. 4 wherein the hawser indicated at 9 leads to the tow hook and the hawser portion indicated at 9 leads to the winch.

In the embodiment of FIGS. 3 and 4 a hawser opening frame 13 is in the form of a slidable ring and can be displaced transversely between a pair of vertically spaced cross braces 14, and 15. A pair of vertical longitudinal braces 16 support the cross braces I4 and I5 and are arranged on both sides of the longitudinal axis of the ship so that an angle of 20 is formed with respect to the longitudinal axis of the ship between the pivot l and the hawser opening frame 13 positioned sternwardly of the pivot l. The vertical members 16 thus limit the transverse movement of the hawser frame 13. A resilient element 14 may be provided against each of the vertical supports 16 to dampen the impact of the frame 13 against the vertical supports.

In the modification of FIGS. 5410, the towing hook is no longer arranged at the pivot l but is located sternwardly thereof approximately on body section one. As can be seen in FIG. 5, a tow hook 2 is connected to pivot l by means of an intermediate element 17 in the form of a rigid link or beam. The intermediate element may also comprise a chain as shown in FIGS. 9 and 10 or some other flexible structure. Lateral pivoting movement of the intermediate link 17 is limited by a pair of abutment or stop members 18 and 19 positioned on both sides of the longitudinal axis of the ship and inter connected by a transverse member 20 which is curved as can be seen in FIG. 5 and which provides a guide path for the intermediate element T7 or for the tow hook 2. The tow hook 2' is pivotally mounted on a pin 31 on the intermediate element 17 and is thus pivotable in the plane of pivoting of the intermediate element.

The transverse member 20 may be provided with a profiled section in the form of an Ibeam as shown in FIG. 6. The inner surfaces of the flanges provide running surfaces for rollers 21 mounted in a bracket 24 secured to the outer end of intermediate element 17. By guiding the end of the intermediate element in this manner vertical movement of this intermediate element is prevented.

In FIG. 7, there is shown a transverse member 20' in the form of a hollow or box structure within which are guided rollers 22 mounted on the end of the intermediate element 17. The member 20 is provided with side walls 23 upon which rollers 25 are journalled in brackets 24. The rollers 25 will thus guide the intermediate element 17 horizontally at the instant that the tow hook is bent with respect to the intermediate element.

As may be seen in FIG. 8, the transverse member 20" is provided with rounded or curved sides in section and the rounded surfaces provide the running surfaces for correspondingly shaped rollers 26 journalled in the bracket 24" which is mounted on the end of the intermediate element 17.

In the modification of FIGS. 9 and 10 a transverse member 27 interconnecting the abutments l8 and 19 has a circular cross section and has a smaller radius of curvature at the ends thereof than in the remaining portion of the member. A roller 28 is mounted on pin 31 which is carried in the bracket at the end of intermediate element 17' which is in the form of a chain whose other end is pivotally connected to the ship at 1". The tow hook 2 is provided with a slot 29 within which is received the transverse member 27. An additional curved bracket 30 is provided to function as a bearing surface for the two hook 2. The decreasing radii of curvature at the ends of bracket 27 provides for a gradual displacement of the point of engagement from the hawser sternwardly of the abutments 18 and 19. When the hawser begins to move transversely outwardly of the angle of about 25 as shown in FIG. 9 the tow hook 2 will contact either of the abutments 18 or 19. The tow hook is pivotally mounted on pin 31 of the intermediate element 17. As the hawser becomes oriented transversely and the intermediate element 17' contacts abutment 18 or 19 or rollers 28 rolls onto the end portions of transverse member 27 the tow hook 2 can be pivoted further about pin 31 during further transverse movement of the hawser. The intermediate element 17 and the tow hook 2" thus no longer comprise a single unit with respect to the direction of forces. As the transverse orientation of tow hook 2 increases, the point of engagement of the hawser is therefore displaced from pivot l sternwardly to the corresponding abutment 18 or 19.

It is therefore apparent that the intermediate element can be either a rigid member of a flexible member such as a chain and that the tow hook and intermediate member will function as a unit only until the lateral abutments are contacted by the towing hook. As soon as the towing hook contacts either abutment the hook is pivoted and the point of engagement of the hawser is displaced further and further sternwardly as the angle of pivoting of the tow hook increases until the point of displacement is located on one of the abutments in its end position. The various modifications of the present invention all eliminate rubbing or undue friction forces upon the hawser. By decreasing the radius of curvature at the ends of the transverse member 27 there is provided a gradual transition between the two points of engagement of the hawser.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. A device for displacing the point of engagement of a hawser on a ship wherein the hawser extends from the stern of a towing ship comprising means defining a point on substantially the rear quarter of the length of the ship at which a hawser pivotally extends therefrom, means sternwardly from said pivot point between the stern and said pivot point for defining a pivot axis in the vertical plane of the longitudinal axis of the ship, a rocker arm pivotally mounted on said pivot axis and having a hawser opening on the end thereof, and abutment means on both sides of said longitudinal axis vertical plane sternwardly of said pivot point and engageable by said rocker arm to limit the range of pivoting thereof.

2. A device as claimed in claim 1 wherein said pivot axis is below said rocker arm hawser opening.

3. A device as claimed in claim 2 wherein said pivot axis is perpendicular to said rocker arm hawser opening.

4. A device as claimed in claim 1 and comprising a fluid pressure cylinder operatively connected to said rocker arm to pivot said arm.

5. A device as claimed in claim 4 wherein said cylinder comprises one of said abutment means.

6. A device as claimed in claim 4 wherein said cylinder comprises means for absorbing shocks from said

Claims (6)

1. A device for displacing the point of engagement of a hawser on a ship wherein the hawser extends from the stern of a towing ship comprising means defining a point on substantially the rear quarter of the length of the ship at which a hawser pivotally extends therefrom, means sternwardly from said pivot point between the stern and said pivot point for defining a pivot axis in the vertical plane of the longitudinal axis of the ship, a rocker arm pivotally mounted on said pivot axis and having a hawser opening on the end thereof, and abutment means on both sides of said longitudinal axis vertical plane sternwardly of said pivot point and engageable by said rocker arm to limit the range of pivoting thereof.

2. A device as claimed in claim 1 wherein said pivot axis is below said rocker arm hawser opening.

3. A device as claimed in claim 2 wherein said pivot axis is perpendicular to said rocker arm hawser opening.

4. A device as claimed in claim 1 and comprising a fluid pressure cylinder operatively connected to said rocker arm to pivot said arm.

5. A device as claimed in claim 4 wherein said cylinder comprises one of said abutment means.

6. A device as claimed in claim 4 wherein said cylinder comprises means for absorbing shocks from said rocker arm.

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