GB2135261A

GB2135261A - All weather mooring systems

Info

Publication number: GB2135261A
Application number: GB08300824A
Authority: GB
Inventors: Barney Wikiriwhi
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-01-13
Filing date: 1983-01-13
Publication date: 1984-08-30
Also published as: GB8300824D0

Abstract

A floating mooring buoy 1 is guided by a structure 5,6 which allows the buoy 1 to move in a vertical direction only. All wave motion at the stern of a vessel moored to the buoy 1 is thus absorbed without having to pay out the stern mooring line. <IMAGE>

Description

SPECIFICATION All weather mooring system The present invention relates to mooring systems for mooring supply boats and other craft to offshore marine installations such as oil rig platforms located in situations where seas may be rough and weather adverse.

In the normal mooring procedure, supply boats drop anchor off the bow or tie up to an existing buoy away from the platform, opposite the loading/ unloading facility and approximately at right angles to it. The vessel then comes astern to the facility, where the conventional mooring system attaches by passing lines with the platform crane. When weather conditions are bad and it is necessary to pay out the stern mooring line, rough water may cause heaving lines which represent a serious threat to personnel, who may have to "go below" and catch them. The invention seeks to remove this danger, and this is done by providing a floating mooring buoy secured to the platform and free to move in a vertical direction only with movement of the waves.

In order that the invention may be clearly understood, a preferred embodiment thereof will now be described by way of example only with reference to the accompanying drawing, in which: Figure 1 is a schematic side view of the mooring system, and Figure 2 is a top plan view of the floating buoy with its mooring shackle, constrained to move in contact with vertical pipes secured to the platform.

The mooring system incorporates a floating mooring buoy comprised of a buoyancy tank 1 to which is affixed a conventional mooring shackle 2. The mooring buoy can move freely in a vertical direction, using specially constructed sheaves 3 and 4 secured to the buoyancy tank 1. Three pairs of sheaves 3 travel along two reinforced vertical pipes 5 to hold the forward section of the mooring buoy, while two sheaves 4 at the rear section travel along a pipe 6 which acts as a guide. The pipes 5 and 6 form a reinforced sliding race for the mooring buoy.

These forward and rear pipes 5,6 are held together outside the mooring area of the buoy by means not shown in the drawing, so as to constitute a reinforced structure which is fixed to the platform.

A platform leg 8 is shown in Figure 1, together with a platform jetty 9; the structure including pipes 5 and 6 is fixed to the platform so as to be set slightly behind the face of existing platform jetties such as jetty 9. In this way, shackle 2 will extend a little beyond the face of the jetty to allow easy access.

By extending the guide pipes 5, 6, the mooring buoy can be lifted clear of the sea when not in use.

This permits servicing and painting or sandblasting whenever necessary.

The tank 1 need have only sufficient buoyancy to keep the mooring buoy afloat, since the moored vessel will tend to pull the buoy under the water in accordance with movement of the waves and may possibly lift the buoy clear of the water as well. By use of this system, all wave motion at the stern of the vessel is absorbed, and distance and positioning are governed by how much is hauled in or paid out on the bow line.

CLAIMS (filed on 21/3/83) 1. A mooring system comprising a floating mooring buoy and a buoy guiding structure which allows the buoy to move in a vertical direction only.

2. A mooring system as claimed in claim 1, in which the buoy guiding structure comprises a plurality of vertical guide members, the buoy carrying sheaves which run along the guide members.

3. A mooring system as claimed in claim 2, in which a projection on the buoy extends between two adjacent vertical guide members and carries a shackle.

4. A mooring system as claimed in claim 2 or 3, in which the vertical guide members are constituted by pipes.

5. A mooring system as claimed in any preceding claim, in which the guiding structure is fixed to an offshore marine installation.

6. A mooring system substantially as described with reference to, and as shown in, the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION All weather mooring system The present invention relates to mooring systems for mooring supply boats and other craft to offshore marine installations such as oil rig platforms located in situations where seas may be rough and weather adverse. In the normal mooring procedure, supply boats drop anchor off the bow or tie up to an existing buoy away from the platform, opposite the loading/ unloading facility and approximately at right angles to it. The vessel then comes astern to the facility, where the conventional mooring system attaches by passing lines with the platform crane. When weather conditions are bad and it is necessary to pay out the stern mooring line, rough water may cause heaving lines which represent a serious threat to personnel, who may have to "go below" and catch them. The invention seeks to remove this danger, and this is done by providing a floating mooring buoy secured to the platform and free to move in a vertical direction only with movement of the waves. In order that the invention may be clearly understood, a preferred embodiment thereof will now be described by way of example only with reference to the accompanying drawing, in which: Figure 1 is a schematic side view of the mooring system, and Figure 2 is a top plan view of the floating buoy with its mooring shackle, constrained to move in contact with vertical pipes secured to the platform. The mooring system incorporates a floating mooring buoy comprised of a buoyancy tank 1 to which is affixed a conventional mooring shackle 2. The mooring buoy can move freely in a vertical direction, using specially constructed sheaves 3 and 4 secured to the buoyancy tank 1. Three pairs of sheaves 3 travel along two reinforced vertical pipes 5 to hold the forward section of the mooring buoy, while two sheaves 4 at the rear section travel along a pipe 6 which acts as a guide. The pipes 5 and 6 form a reinforced sliding race for the mooring buoy. These forward and rear pipes 5,6 are held together outside the mooring area of the buoy by means not shown in the drawing, so as to constitute a reinforced structure which is fixed to the platform. A platform leg 8 is shown in Figure 1, together with a platform jetty 9; the structure including pipes 5 and 6 is fixed to the platform so as to be set slightly behind the face of existing platform jetties such as jetty 9. In this way, shackle 2 will extend a little beyond the face of the jetty to allow easy access. By extending the guide pipes 5, 6, the mooring buoy can be lifted clear of the sea when not in use. This permits servicing and painting or sandblasting whenever necessary. The tank 1 need have only sufficient buoyancy to keep the mooring buoy afloat, since the moored vessel will tend to pull the buoy under the water in accordance with movement of the waves and may possibly lift the buoy clear of the water as well. By use of this system, all wave motion at the stern of the vessel is absorbed, and distance and positioning are governed by how much is hauled in or paid out on the bow line. CLAIMS (filed on 21/3/83)

1. A mooring system comprising a floating mooring buoy and a buoy guiding structure which allows the buoy to move in a vertical direction only.