It looks like from your picture that is a "hose like material" used for chafe guard. If you are using synthetic line than heat dissipation is more of a concern for failure than being cut. In other words more failures from melting than wearing through. So porous leather or canvas that lets rain/seawater through is superior to hose that restricts water and keeps heat in. Perhaps you already know all that and I am misinterpreting your picture but the effect of heat on failed mooring or dock lines was a surprise to me and as storm season gets into full swing I thought I would mention it.