Tug barge lightering connection system

Abstract

A lightering connection system is provided for coupling a tug boat to a barge, where the connection permits relative vertical movement between the tug and barge while maintaining horizontal movement control between the vessels. The tug boat has port and starboard retractable rams having coupler heads which engage the barge along inboard port and starboard vertical receiver channels. The coupler heads and vertical receiver channels are provided with waveform surfaces to permit interlocking engagement between the tug boat and barge. The waveform surfaces also permit smooth relative movement of the surfaces as the ram disengages in performing the lightering operation. The coupler heads and vertical channel receivers have a mating angular construction to maintain horizontal movement control between the tug and barge during the lightering operation.

1 . A coupler and receiver assembly for connecting a pusher vessel within a stern notch of a barge, the assembly comprising: 
 a pair of rams provided on lateral sides of the pusher vessel, a coupler head attached to each of the rams,    receiver channels for receiving each coupler head provided on the barge,    each receiver channel comprising first and second generally opposed sidewalls,    each of the coupler heads comprising lateral edges, at least one of the lateral edges of each coupler head having a primary waveform surface with a plurality of rounded, non-angular projections, at least one of the first and second sidewalls of each of the receiver channels having similar secondary waveform surfaces adapted to mate with the lateral edge of the coupler heads having the primary waveform surface.    
   
   
       2 . The coupler and receiver assembly of  claim 1  in which the pusher vessel is adapted for engagement with the barge when the primary waveform surfaces of the lateral edges of the coupler heads mate with the secondary waveform surfaces of the receiver channels such that crests of a wave of a first waveform surface lie completely within troughs of an opposing second waveform surface.  
   
   
       3 . The coupler and receiver assembly of  claim 1  in which the sidewalls of the receiver channels are angularly disposed towards each other such that longitudinal planes in which the sidewalls lie diverge outwardly each from each other, and the lateral edges of the coupler heads are angularly disposed towards each other such that longitudinal planes in which the lateral edges lie diverge towards each other towards a front of the coupler head.  
   
   
       4 . The coupler and receiver assembly of  claim 1  in which the rams are adapted for automated extension and retraction to effect engagement and disengagement of the pusher vessel with and from the barge, respectively.  
   
   
       5 . The coupler and receiver assembly of  claim 3  in which the rams are adapted for extension and retraction to effect engagement and disengagement of the pusher vessel with and from the barge, respectively, the amplitudes of waves of the primary and secondary waveform surfaces having a combined value less than a distance equal to that necessary for the coupler heads to be completely withdrawn from the receiver channels.  
   
   
       6 . The coupler and receiver assembly of  claim 5  in which relative vertical movement between the pusher vessel and barge is enabled when the crests of waves are completely withdrawn from troughs of opposing waveform surfaces.  
   
   
       7 . The coupler and receiver assembly of  claim 6  in which relative horizontal movement of the pusher vessel is limited when the coupler heads are at least partially within the receiver channels.  
   
   
       8 . The coupler and receiver assembly of  claim 7  in which the primary waveform surface is provided on both lateral edges of the coupler heads, and the secondary waveform surfaces are provided on both the first and second sidewalls of the receiver channels.  
   
   
       9 . The coupler and receiver assembly of  claim 1  in which the respective waveform surfaces of the lateral edges of the coupler heads and the sidewalls of the receiver channels have an amplitude greater than zero, but less than a value representing a distance of a pitch of the waveform.  
   
   
       10 . The coupler and receiver assembly of  claim 9  in which a ratio of the amplitude to pitch is 1:7.  
   
   
       11 . A coupler and receiver assembly for maintaining a water level position of a pusher vessel within a stern notch of a barge during a lightering operation, the assembly comprising: 
 a pair of rams provided on lateral sides of the pusher vessel,    a coupler head attached to each of the rams, the coupler head having lateral edges angularly disposed towards each other at the front end of the coupler head,    receiver channels for receiving each coupler head provided on the barge,    each receiver channel comprising first and second generally opposed sidewalls, the sidewalls being angularly disposed away from each other at the longitudinal opening of the receiver channel, the angular disposition of the sidewalls being equal but opposite to the angular disposition of the lateral edges of the coupler head,    each of the coupler heads comprising lateral edges having a primary waveform surface with a plurality of rounded, non-angular projections, each of the first and second sidewalls having similar secondary waveform surfaces with a plurality of rounded, non-angular projections adapted to mate with the lateral edges of the coupler heads, the rams being adapted for extraction and retraction to maneuver the coupler heads into engagement with and disengagement from the receiver channels, whereby the primary waveform surfaces of the lateral edges of the coupler heads are capable of being brought into mating engagement with the secondary waveform surfaces of the first and second sidewalls of the receiver channels to secure the pusher vessel within the stern notch of the barge.    
   
   
       12 . The coupler and receiver assembly of  claim 11  in which the pusher vessel is restricted from relative vertical movement with respect to the barge when crests of a wave of a first waveform surface lie completely within troughs of an opposing second waveform surface.  
   
   
       13 . The coupler and receiver assembly of  claim 12  in which the barge is adapted for relative vertical movement with respect to the pusher vessel when the barge is subject to load variations, the rams being adapted for retraction to bring the crests of the wave of the first waveform surface out of engagement with the troughs of the opposing second waveform surface, the coupler heads and receiver channels being adapted to slide with respect to each other in a vertical direction when the crest of the first waveform surface is not overlapping the crest of the second waveform surface.  
   
   
       14 . The coupler and receiver assembly of  claim 13  in which relative horizontal movement of the pusher vessel is limited when the coupler heads are at least partially within the receiver channels.  
   
   
       15 . The coupler and receiver assembly of  claim 11  in which the respective waveform surfaces of the lateral edges and sidewalls have an amplitude greater than zero, but less than a value representing a distance of a pitch of the waveform.  
   
   
       16 . The coupler and receiver assembly of  claim 15  in which a ratio of the amplitude to pitch is 1:7.  
   
   
       17 . An assembly for coupling a first vessel with a second vessel, the assembly comprising: 
 a ram provided on the first vessel;    a coupler head attached to the ram; and    a receiver channel provided on the second vessel for receiving the coupler head, with the receiver channel including first and second sidewalls,    wherein the coupler head includes first and second lateral edges, with at least one of the lateral edges having a primary waveform surface presenting a plurality of curved, non-angular projections, and at least one of the first and second sidewalls of the receiver channel having a similar secondary waveform surface adapted to mate with the lateral edge of the coupler head having the primary waveform surface.    
   
   
       18 . In a system for selectively coupling a first vessel with a second vessel, wherein the system includes—
 a first ram including a first coupler head, the first ram being mounted on the first vessel so as to be selectively extendable outwardly from a first side of the first vessel;    a first receiver channel provided on a first side of a notch in the second vessel, oriented substantially vertically, and operable to receive the first coupler head when the first vessel is located within the notch and the first ram is extended;    a second ram including a second coupler head, the second ram being mounted on the first vessel so as to be selectively extendable outwardly from a second side of the first vessel; and    a second receiver channel provided on a second side of the notch in the second vessel, oriented substantially vertically, and operable to receive the second coupler head when the first vessel is located within the notch and the second ram is extended;    the improvement comprising:    the first and second coupler heads each having left and right sides, with each of the left and right sides including a coupler head surface presenting a first plurality of low amplitude, rounded projections; and    the first and second receiver channels each having left and right sides, with each of the left and right sides including a receiver channel surface presenting a second plurality of low amplitude, rounded projections,    wherein the first and second pluralities of low amplitude, rounded projections interact so as to allow for vertical sliding movement between each coupler head and its respective receiver channel without requiring full withdrawal of the coupler head from the receiver channel, thereby allowing for relative vertical movement between the first and second vessels while substantially eliminating other relative movement.