as metal or plastic referring now to fig6 in another embodiment the stiffening mechanism is the fibers 24 which comprise the outer surface of the rope being stiffened this can be accomplished by impregnating the fibers with an adhesive if the rope is made from a synthetic heat sensitive material a segment of the rope can be stiffened by applying heat and possibly a compressive force to the segment in another embodiment fig8 the entire collar 16 is squeezed with a crimping tool to where its outer diameter is close to the outer diameter of the rope 10 this allows the stiffened segment to have essentially the same diameter as the rest of the rope in fig9 the collar 26 has a smaller diameter and is placed between the outer sheath 28 and inner core 30 of the rope while the various types of stiffening mechanisms are described separately multiple stiffening devices could be used together for example a collar could be attached both by crimping and by an adhesive in any event once the stiffening mechanism has been applied to the rope the rope is used in the normal manner when someone is descending the rope the stiffened segment will warn them as they approach the bottom of the rope if the rope is being used in conjunction with a.