replacing shock cord loop on standsrd Hobie sail

Hi,
I need to replace the cord loop that holds down the bottom of the standard hobie sail t the mast. I have new 1/4" cord. My question is how do I complete the loop. The existing loop is joined very smoothly under a plastic sleeve. Its almost the same thickness as the cord, dont know what kind of knot could be so thin. Suppose I could cut open the plastic to see what is there. Thank you for any advice.