GB2130540A

GB2130540A - Drive and control gear protection means in a propeller-driven watercraft

Info

Publication number: GB2130540A
Application number: GB08330024A
Authority: GB
Inventors: Fritz Petersen
Original assignee: Howaldtswerke Deutsche Werft GmbH
Current assignee: ThyssenKrupp Marine Systems GmbH
Priority date: 1982-11-16
Filing date: 1983-11-10
Publication date: 1984-06-06
Also published as: DE3242290A1; GB8330024D0; GB2130540B; DE3242290C2; SE8306255D0; SE8306255L

Abstract

Deflectors for drive and control gear of a ship, particularly a submarine, comprise straight, flexible, rod- shaped or wire-shaped deflector elements (6, 7). The deflector elements (6, 7) are each tensioned, in an arrangement approximately surrounding the flow of water to the propeller, between respective fixed points (A, B, C, D) at the immovable fins and retaining parts firmly connected to the stern (1) of the ship. The elements (6, 7) include a screw shackle (9) and a spring cartridge (14). <IMAGE>

Description

SPECIFICATION Drive and control gear protection means in a propeller-driven watercraft The present invention relates to propellerdriven watercraft and has particular reference to drive and control gear protection means in such watercraft, especially a submarine.

Deflectors for ship drive and control gear are used for protection thereof from ropes and hawsers fastened to the ship, especially for the protection of control and supply lines leading to probes, measuring devices or similar which extend from the ship or to divers cooperating with the ship. Such lines are present, for example, in the use of submarines for the monitoring equipment for underwater conveying of mineral oil and natural gas and in the use of similar floating bodies which are movable underwater and from which operations can be performed at the sea bed. Lines of that kind can easily be drawn in by the propeller and destroyed unless this is prevented by the deflector.

DE-PS 305 1 32 shows rod or wire cable deflector elements which extend substantially tangentially at an elevator rudder of a submarine and are fastened to the hull before or behind the axis of a rudder. They are movably mounted at their ends so that they can adapt themselves to the setting of the rudder.

US-PS 973 227 shows a pivotable arm for the protection of diving planes during surface travel. Wire ropes can be fastened at the arm and serve as deflectors when the arm is pivoted over the planes. Both known arrangments are provided only for the protection of the front and rear edges of the planes or rudders. They can also keep away vertically hanging or floating ropes as well as other objects from the planes or rudders. However, they are not suitable to prevent ropes or similar, which float loosely in the water alongside a submarine, from being sucked in by the propeller.

In the case of ships' propellers which are arranged in orifices or tubes, their entry edge acts like a deflector when the lines are relatively thick and stiff. However, thin lines cannot be kept with sufficiently safety away from the water flowing into the orifice. Moreover, many ships' propellers are constructed without orifices of that kind and disturbance of the current to the propeller by deflecting elements is undesired.

There is thus a need for deflector elements to prevent ropes and lines floating beside a ship from being drawn in by the current to the propeller and to the rudders, such deflector elements preferably having a long operating life in spite of the current forces acting at them.

According to the present invention there is provided a propeller-driven watercraft provided at its stern with resiliently flexible rectilinear and rod-like deflector elements arranged generally around the path of suction water flow to the propeller and connected under tension between respective fixed points at immovable means firmly connected to the stern of the craft, the immovable means comprising at least one of fins and retaining means.

In a preferred embodiment rectilinear, flexible deflector elements are resiliently tensioned, in an arrangement surrounding the current to the propeller, between several fixed points. The deflector elements can consist of wire ropes. It has, however, been found that the deflector elements are exposed to strong deformation loadings by the propeller current and particularly also by the current at the control rudders during normal and rapid travel of the ship, leading to creation of tension and bending forces as well as oscillations which can lead to permanent extension and even to the fracture of, for example, wire ropes.

Preferably, therefore, the deflector elements are high strength rods of a flexible material, for example alloyed steel of high tensile strength.

Expediently, a spring cartridge, which is so constructed that it makes possible the setting of a bias and a transient resilient deformation of spring elements disposed therein, is arranged at at least one end of each deflector element. The deflector elements and the spring cartridges are arranged to be movable to all sides at the fixed points. In addition, the deflector elements are expediently provided with a cladding having a streamlined profile.

The resilient tensioning of the deflector elements and the selected material of the rods to a limited degree permits deformations which are unavoidable due to the current, but prevents stretching and then oscillation of the elements in the propeller current. The streamlined cladding not only reduces the flow resistance of the deflector elements but also reduces the risk of oscillation.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the stern of a submarine embodying the present invention; Figure 2 is a plan view of the stern of the submarine; Figure 3 is an end view of part of the stern; Figure 4 is a sectional view, to an enlarged scale, of deflector elements at the stern; and Figure 5 is a cross-section of one such deflector element.

Referring now to the drawings, there is shown the stern section 1 of a submarine, a propeller 2 being provided at the stern. Fixed horizontal fins 3 and movable diving planes 4 and rudders 5 and 8 are mounted on the submarine hull in front of the propeller 2. A deflector element 6 extends from a fixed point A at the top at the rotational axis of the upper rudder 5 to a fixed point 8 on each fixed horizontal fin 3. A further deflector element 7 extends from a fixed point C at the underside of each fin 3 to a fixed point D at a fixed fin 8a in front of the lower rudder 8.

As Fig. 4 clearly shows, the deflector element 6 or 7 comprises a rod 61 or 71 of a flexible material of high tensile strength. The rod is provided over the greater part of its length with a flow cladding 62 of synthetic, for example plastics, material.

Each upper deflector element 6 is fastened at its upper end by a screw shackle 9 and Cardan joint halves 10 and 11 at the fixed point A on a holder 12, which is mounted on a spigot 1 3 at the top at the upper rudder 5.

The lower end of the deflector element 6 is fastened to a spring cartridge 14, which is mounted by further Cardan joint halves 10 and 11 at the fixed point B on one of the fins 3.

The spring cartridge 14 contains a number of deformable rubber discs 15, between which individual metal discs 1 6 are arranged.

A portion 63 of the rod 61 is fastened to the innermost metal disc 1 6a and guided in a flange 1 7 of the cartridge 14. On tensioning of the rod 61, the discs 1 6 are compressed in the cartridge 14 in accordance with the magnitude of loading.

Each lower deflector element 7 is mounted at a retaining part 1 8 on the underside of one of the fins 3 at the fixed point C and extends to the fixed point D at a retaining part 1 9 on the fin 8a. A screw shackle 9 and a spring cartridge 14 of the afore-described kind are also disposed connected to each lower deflector element 7.

According to the kind of the ship, a greater or lesser number of the deflector elements 6 and 7 illustrated in the drawings can be used in order to prevent entrainment, by the water flowing towards the propeller, of ropes or lines which could be damaged by the propeller or get caught in the propeller or on the movable planes and rudders and impair manoeuvrability. If the propeller is arranged in front of the rudders in a ship, the deflector elements should be mounted in suitable manner in front of the propeller and several deflector elements can be provided one behind the other so that the flow cross-section to the propeller is not restricted. The streamlined cladding 62 of each high strength rod 61 or 71 can be adapted to the current direction.

The cladding reduces the resistance of the deflector element, which is thereby loaded less in bending.

The spring cartridges 14 illustrated in the drawings show only a preferred construction.

Other spring devices are possible provided they are resistant to sea water and, if so required, remain capable of functioning at depth.

Claims

1. A propeller-driven watercraft provided at its stern-with resiliently flexible rectilinear and rod-like deflector elements arranged generally around the path of suction water flow to the propeller and connected under tension between respective fixed points at immovable means firmly connected to the stern of the craft, the immovable means comprising at least one of fins and retaining means.

2. A watercraft as claimed in claim 1, wherein each of the deflector elements comprises a rod of flexible material having a high tensile strength.

3. A watercraft as claimed in claim 2, wherein the rod of each deflector element has a streamlined cladding.

4. A watercraft as claimed in either claim 1 or claim 2, wherein each of the deflector elements is connected at one end thereof to a respective spring cartridge supplying the resilient component of the deflector element flexure and the tension in the deflector element connection between the respective fixed points.

5. A watercraft as claimed in claim 4, wherein each of the cartridges comprises alternately arranged metallic discs and rubber discs.

6. A watercraft as claimed in either claim 3 or claim 4, wherein the deflector elements and cartridges are connected to the immovable means by universal joints.

7. A watercraft as claimed in any one of the preceding claims, the watercraft being a submarine.

8. A propeller-driven watercraft substantially as hereinbefore described with reference to the accompanying drawings.