Aw geeze. I guess, there are no U.S. Navy veterans or sailors here. The navy classifies "rope" as that made from wire. They classify line made from fiber as "line." Really big line can be as big as several inches in diameter, when it becomes known as a "howser."
Enough for history. For extended outdoor use, especially in sun, the polypropylene line has a lot of drawbacks. It deteriorates from UV light, slowly loosing it's strength until it is very weak. The good thing about it for water use is that it floats. Many times it is easier to splice it than to make a good knot that can be easily untied. Once a knot has been in place, it is hard to get the mis-shapen area out of the polypropylene.
Nylon makes a great outdoor rope with a very long life, and it has great shock resistance. It is relatively soft. Knots are easy.
Polyester is one of the nicest. It is soft and very flexible. It is impervious to UV and most chemicals. It it one of the easiest for holding and removing knots.
Good knots,
Ken
