Double braid polyester is used in numerous applications as well. 3/4" is a larger diameter and often used in the rigging, towing, secondary mooring lines, and tugging applications. There are many other uses for it as well, for even as simple things as barrier cord (although it is an overkill for strength). A double braid rope is a braided rope, over another braided rope. This increases the strength of the rope. Often when used in the rigging or for winch line applications, a coating is put over top to increase the life of the rope and help with abrasion resistant properties. Polyester has increased abrasion resistant properties over polypropylene ropes. This particular rope has a tensile strength of approx. 17,000 lbs. Its a very strong rope with little stretch. Smaller diameters of this rope have numerous applications as well. Check other blogs for great information on smaller diameters of this rope. Thanks! The Knotty Girlz @ www.cbknot.com