AU726885B2 - Mooring system - Google Patents

Description

S F Ref: 379155

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Phillip Charles Heaney Sara Street Toronto New South Wales 2283

AUSTRALIA

Phillip Charles Heaney Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Mooring System ASSOCIATED PROVISIONAL APPLICATION DETAILS [311 Application No(s) [331 Country P01497

AU

[32] Application Date 7 August 1996 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815 MOORING SYSTEM Technical Field The present invention relates to mooring systems for vessels.

Background of the Invention Conventional mooring systems, as shown in Figure 1, typically comprise a heavy concrete mooring block 1 located on the waterway floor 2 with a heavy ground chain 3 fixed thereto. A lighter riser chain 4 is fixed to the distal end of the heavy ground chain 3 and a rope 5 is further attached to the riser chain 4 via a swivel 6. A mooring buoy 7 is attached to the distal end of the rope 5 to allow the same to be 10 retrieved from the water surface 9 and fastened to a vessel 8. In this conventional .o arrangement, the various mooring line components 3,4 and 5 are sized in length to allow for variations in the level of the water surface 9 as the tide ebbs and flows and S•such that at least the heavy ground chain 3 tends to lie on the waterway floor 2 in all but heavy conditions to reduce and dampen the direct load on the mooring block 1.

15 The interaction of varying tidal flow and wind conditions act on the vessel 8 to swing the same about the mooring block 1, dragging at least the heavy ground chain 3 along the waterway floor and damaging the same and vegetation growing thereon. This destroys the habitat and food supply for fish in the immediate area, reducing fish stocks for local fishing industries. The excess length of mooring line 3,4 and 5 required to allow for tidal variations and laying of heavy ground chain 3 along the waterway floor 2 results in a large swing radius about the mooring block 1 through which the vessel 8 travels, limiting the number of vessels that can safely be moored in a given area and thereby creating a demand for mooring spaces far exceeding supply in prime areas. Any reduction in length of the mooring line components 3,4 or 5 will result in reduced damping and increased load acting directly on the mooring block 1, with a consequential increase in possible fatigue damage to fittings.

[n:\libl]00492:GJG Object of the Invention It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

Summary of the Invention There is disclosed herein a mooring system for securing a vessel in a waterway comprising: a mooring block to be located on a floor of said waterway at a mooring site; a line attached at a first end thereof to said mooring block and adapted at a second end thereof to be secured to said vessel; a first buoy attached to said second end of said line, adapted to be retrieved from a surface of said waterway from said vessel; and a floating second buoy attached to said line between said first and second ends such that said line is substantially suspended above said waterway floor throughout a maximum tidal range at said mooring site when said second end is attached to said vessel; wherein a portion of said line, bounded by said first and second buoys, is suspended freely between said buoys.

Preferably a length of said line between said first end and said second buoy is approximately equal to the depth of said waterway at said mooring site at a king tide.

Preferably, said line includes a first rope at said first end.

20 Preferably said line further includes a first chain attaching said first rope to said second buoy.

Preferably said first rope and said first chain are attached via swivel means.

Preferably said line further includes a second chain between said second buoy and said second end. Preferably said second chain is of heavier gauge than said first chain.

Preferably said line further includes a second rope at said second end.

Preferably said first rope has a length within 25% of said maximum tidal range.

Preferably said second chain has a length within 25% of the depth of said waterway at said mooring site at dead low tide.

Preferably said second buoy includes means for attaching said second end thereto whilst said vessel is away from said mooring site.

[TI:\DAYIB\IBLL] 10025.do:e [I.\DAYLI1B\LIBLL] l0025.doc:eaa Brief Description of the Drawings A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a schematic elevational view of a conventional mooring system.

Figure 2 is a schematic elevational view of a mooring system according to the invention.

Detailed Description of the Preferred Embodiment A conventional concrete mooring block 11 is provided on the waterway floor 2 at the mooring site of the vessel 8. A float rope 12, preferably made from heavy silver rope, is attached to the mooring block 11, and in the preferred embodiment is sized in length to be approximately equal to the maximum tidal range at the mooring site. A swivel 13 attaches the float rope 12 to a riser chain 14, which is preferably of a length approximately equal to the depth of the waterway at the mooring site at dead low tide, such that the float rope 12 and riser chain 14 combined length is approximately and at least equal to the depth at a king tide. A support buoy 15 is attached to the end of the riser chain 14 and floats on the waterway surface 9, supporting the weight of the float rope 12 and riser chain 14. As the combined length of the float rope 12 and riser chain 14 is minimised, the support buoy 15 remains generally above the mooring block 11 in all but extreme conditions (as explained below). A heavy chain 16 is attached to the 20 support buoy 15 and also to the riser chain 14 so that, if the support buoy inadvertently breaks free, the heavy chain 16 will still be secured (indirectly) to the mooring block 11. The heavy chain 16 should have a length approximately equal to the depth at the mooring site at low tide. The chains 14,16 and the swivel 13 are preferably made from galvanised steel. A second rope 17, preferably silver rope, is attached at one end to the end of the heavy chain 16, and at the other end to a conventional mooring buoy 18. The second rope 17 has a length of the same order as that of the heavy chain 16.

A frame 19 including a hook 20 may be provided on the upper side of the support buoy 15 for placing the second rope 17 and mooring buoy 18 thereon whilst the [n:\libll]00492:GJG 4 vessel is away from the mooring, facilitating easy retrieval of the mooring buoy 18 by a person on the deck of the vessel 8 when mooring, and reducing the possibility of damage to the mooring buoy 18 and second rope 17 from other passing vessels when the vessel 8 is away from the mooring site.

During the mooring sequence the vessel 8 approaches the mooring, retrieves the mooring buoy 18 and secures the second rope 17 to the bow of the vessel 8 in the conventional manner, typically by securing a loop provided in the end of the second rope 17 to a bollard or cleat provided on the deck of the vessel 8. The heavy chain 16 acts as a catenary, the weight of which reacts, at least partially, loads applied to the mooring system as a result of tidal and wind forces on the vessel 8. The heavy chain 16 and support buoy 15 dampen loads transferred to the mooring block 11, preventing 4o snatching on the mooring block 11 and providing a safer moorage. As conditions become heavier, the catenary increases until the heavy chain 16 and second rope 17 straighten out, and under extreme conditions the support buoy is pulled under the 15 surface 9 to provide a direct line between the mooring block 11 and the vessel 8 via the float rope 12, chains 14,16 and second rope 17. As conditions ease the support buoy resurfaces.

The mooring system of the preferred embodiment prevents damage to vegetation on the waterway floor as the mooring line is substantially suspended above the floor.

The arrangement also results in a reduced swing radius about the mooring block 11, and hence a larger number of vessels can be safely moored in a restricted area.

The mooring system can readily replace a conventional mooring system, utilising the original mooring block 11 and mooring buoy 18, and possibly reusing some mooring line components, depending on condition. The mooring system can also be easily serviced as per a conventional system.

[n:\ibll]00492:GJG

Claims (9)

1. A mooring system for securing a vessel in a waterway comprising: a mooring block to be located on a floor of said waterway at a mooring site; a line attached at a first end thereof to said mooring block and adapted at a second end thereof to be secured to said vessel; a first buoy attached to said second end of said line, adapted to be retrieved from a surface of said waterway from said vessel; and a floating second buoy attached to said line between said first and second ends such that said line is substantially suspended above said waterway floor throughout a maximum tidal range at said mooring site when said second end is attached to said vessel; wherein a portion of said line, bounded by said first and second buoys, is suspended freely between said buoys.

2. The mooring system of claim 1 wherein said line includes a first rope at said first end.

3. The mooring system of claim 2 wherein said first rope has a length within 25% of said maximum tidal range.

4. The mooring system of either of claims 2 and 3 wherein said line further includes a first chain attaching said first rope to said second buoy.

5. The mooring system of claim 4 wherein said first rope and said first chain are attached via swivel means. oo*6. The mooring system of either of claims 4 and 5 wherein said line includes a second chain between said second buoy and said second end. The mooring system of claim 6 wherein said second chain has a length within 25% of the depth of said waterway at said mooring site at dead low tide.

8. The mooring system of either of claims 6 and 7 wherein said second chain is of heavier gauge than said first chain.

9. The mooring system of any one of claims 2 to 8 wherein said line o further includes a second rope at said second end. The mooring system of any one of claims 1 to 9 wherein a length of said line between said first end and said second buoy is approximately equal to the depth of said waterway at said mooring site at a king tide.

11. The mooring system of any one of claims 1 to 10 wherein said second buoy includes means for attaching said second end thereto whilst said vessel is away from said mooring site. [R:\LIBLL]0988 I.doc:MFF 6

12. A mooring system substantially as hereinbefore described with reference to Figure 2. Dated 13 September, 2000 Phillip Charles Heaney Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBLL]09881 .doc:MF