insertion tool 38 shown in fig5 a the leader end of the 100 percent polyolefin yarn is looped through the eye 38a of insertion tool 38 the tool 38 is pulled through the strand being formed within the tubular member 40 by looping the new yarn through the eye 38a of tool 38 and pulling the tool through the strand the new yarn is introduced into the strand without a knot this method insures both a substantially constant diameter and constant strength for the strand and thereby provides a rope of constant strength all of the blended yarns chosen to be replaced with the 100 percent polyolefin yarn are exchanged in a staggered fashion preferably over a twenty foot length of strand to maintain rope strength and diameter uniform throughout the transition region between the floating and sinking portions the transition section thus gradually moves from negative buoyancy to positive with no discernible change in its diameter this is accomplished by employment of the staggered method and further by forming the blended yarns and the 100 percent polyolefin yarn of substantially the same diameter and twisting the yarns forming the strand in one preferred embodiment the floating and sinking rope sections are made easily distinguishable to the eye by utilizing polyolefin yarns of a first color which replace the white blended yarns employed in the sinking portion of the rope thus aiding in a simple differentiation of the sinking and floating rope portions when the proper number of blended yarns have been replaced by 100 percent polyolefin yarns the ratio of blended to polyolefin yarns is maintained throughout the remaining length of the rope typically a floating sinking rope has a sinking rope.