Patent Publication Number: US-5025742-A

Title: Turret mooring for an oil tanker

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a turret type mooring system for a seagoing vessel, such as an oil tanker. 
     2. Description of the Prior Art 
     The use of a turret type mooring for mooring all types of vessels, especially oil tankers, is now becoming more widespread. These types of moorings are typically employed to allow oil to be pumped to and from an oil tanker off-shore, and include a fluid swivel joint which allows an oil pipe on the tanker to rotate relative to a supply or discharge pipe so that excess strain will not be imposed upon the joint by motion of the tanker relative to the mooring. In prior art moorings of this type, a turret support structure is attached externally to the bow of the vessel. As a result, all of the mechanisms of the turret mooring including the fluid swivel joints, flexible piping connections, bearings, etc. are external to the vessel and below the waterline thus making maintenance, repairs and monitoring of the turret mooring and associated equipment difficult or impossible while the mooring is in use. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to provide a turret type mooring for all types of vessels which permits maintenance, repairs and monitoring of the turret mooring and associated equipment to be easily carried out while a vessel is moored and in any loading condition. 
     This and other objects of the invention are achieved through use of a turret mooring which is attached to a vessel so that direct access may be had to the mooring mechanisms from inside the vesel. In a preferred embodiment of the invention, one or more fluid swivel joints, flexible piping connections and main turret bearings are housed within a small compartment in the bow structure of the vessel which can be accessed from within the vessel through a watertight door. As a result, maintenance, repair and monitoring of these parts of the turret mooring can be easily accomplished. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features and advantages of the present invention will become apparent from the following detailed description thereof taking in conjunction with the accompanying drawings in which: 
     FIG. 1 is a side elevation of a vessel with a prior art vessel turret mooring; 
     FIG. 2 is a side elevation of a vessel with a vessel turret mooring constructed in accordance with the present invention, with the various elements of the turret mooring shown in phantom; and 
     FIG. 3 is a partially sectioned side elevation of a vessel showing the turret mooring of FIG. 2 in greater detail. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to a more detailed consideration of the invention, there is illustrated in FIG. 1, a prior art vessel mooring system 10 for a vessel 11 which includes a turret mooring 12. The mooring 12 is mounted externally of a hull 13 of the vessel 11 adjacent a bow 14 by means of a turret support structure 16. The turret mooring 12 includes a fluid swivel joint 18 and a spider 20 to which are attached a plurality of anchor pendants 22 and a flexible hose or pipe 24 for connection to a fluid source or receiver (not shown). The fluid swivel joint 18 rotatably connects the flexible hose or pipe 24 to a length of flexible piping 26 that is attached externally to the vessel structure and leads to oil receiving compartments therein (not shown). Access to the piping 26, swivel joint 18 and associated mechanisms and bearings must be achieved below the waterline external to the vessel 11 for maintenance, repair or monitoring. This is undesireable because it requires either that a diver be employed or that the vessel be put in dry dock to service or monitor the turret mooring 12. 
     The present invention remedies this drawback and a preferred embodiment thereof is illustrated in FIGS. 2 and 3. With specific reference to those figures, it can be seen that the fluid swivel 18, piping 26 and associated mechanisms are all positioned within the bow 14 of the vessel hull 13 below the waterline. An additional bulkhead 30 is built into the front of the bow 14 to form a compartment 32 for reception of the turret mooring assembly 12. The piping 26, fluid swivel joint 18 and associated connections and bearings can be accessed through a watertight door 34 that is formed in the bulkhead 30. An additional access opening 36 is provided to allow access to be gained to the turret mooring assembly 12 externally as illustrated in FIG. 3. A notch 38 is removed from the bow 14 to make room for the spider 20. Thus, the present invention enables the turret mooring 12 to be serviced or monitored from within the vessel hull 13 without taking the vessel 11 or turret mooring 12 out of operation. 
     Although the invention has been disclosed in terms of a preferred embodiment, it will be understood that numerous modification and variations could be made thereto without departing from the true spirit and scope of the invention as set forth in the following claims. For example, although the vessel 11 illustrated in FIGS. 2 and 3 is shown as having a bulbous bow 14 in which is formed the watertight compartment 32, a similar watertight compartment could be formed in a vessel having any other type of bow construction as well. Further, it is not necessary that the mooring assembly 12 be mounted in the bow of the vessel and it will be understood that it could be mounted in any other portion of the hull of the vessel if desired.