The field of the invention pertains to pick-up trucks and the retention of cargo placed in the cargo bed.  In particular, the invention pertains to devices for retaining cargo in the cargo bed where the cargo is much longer than the length the cargo bed. 
Frequently it is necessary to carry lengthy ladders, pipe, lumber, plastic siding and other construction materials that are typically two to four times the length of the cargo bed of the pick-up truck, even with the tailgate down.  In such cases, the cargo is typically tied down with rope and weighted with cement blocks or other heavy objects.  Such methods of retaining the cargo are inconvenient, time consuming and potentially very unsafe in the event the cargo drops from the truck to the highway. 
A variety of devices have been used to retain a cargo in a truck.  One example is the device shown in U.S. Pat.  No.  4,702,653 wherein horizontal bars are mounted on horizontal tracks to retain stacks of boxes in position inside the truck.  U.S. Pat.  No.  5,028,184 discloses a horizontal bar positionable vertically on cut-to-fit wooden posts, the wooden posts in turn positionable on vertical tracks formed in the truck sidewalls. 
Cargo bed liners for pickup trucks have been modified to retain items in cargo beds such as the cargo beds disclosed in U.S. Pat.  No.  4,887,947 and U.S. Pat.  No.  4,958,876.  These bed liners, however, only retain items with partitions within the bed to prevent sliding around in the bed.  There are no features directed to retaining long objects that extend well beyond the bed.