Some recent developments of rope technologies - Further enhancements of high performance ropes

Abstract

Synthetic ropes manufactured from high modulus synthetic fibers have been successfully replacing wire cables in various marine applications, such as mooring, tug and fishing for over 25 years. While there was initial resistance to these high performance synthetic ropes from users of wire rope based on reliability, appearance when used, and initial higher capital cost, experience has shown that synthetic lines provide excellent values in three main areas - safety, quality, and total cost of ownership. The substantial benefits afforded by lightweight, flexible alternatives to wire rope are becoming globally recognized by important advisories such as OCIMF (Oil Company International Marine Forum) and others. As these high performance synthetic lines expand into specialty applications, new technical challenges start to demand the rope manufacturers to advance their rope technologies to the next level. In this paper, we will discuss new technologies developed recently to overcome high levels of technical difficulties and challenges, including the following two areas: 1 Requirements for a rope to perform in high temperature/fire environment; 2 Overcoming the low coefficient of friction nature of rope made with HMPE (High Modulus PolyEthylene) fibers. High Temperature/Fire Environment The use of Aramid fibers in high temperature applications has been popular since their inception. With specially designed passive high temperature resistance coating, the thermal and flame resistance of the Aramid fiber rope can be further enhanced significantly. We will discuss the development, design and testing of this coating technology. High Coefficient of Friction (COF) HMPE The use of High Modulus PolyEthylene (HMPE) fiber is gaining popularity in the cordage industry due to such excellent properties as high strength, low weight, fatigue resistance, and UV resistance. However, the low Coefficient Of Friction (COF) of HMPE fiber presents a challenge when used on winches, capstans, H-bitts and other types of hardware that rely on friction for proper performance. A blended yarn, DPX, was developed to change the surface characteristics of traditional HMPE ropes. DPX is a unique blend of Dyneemareg fiber and polyester that provides a pre-fuzzed appearance and grips better than any HMPE fiber. We will discuss the characteristics and performance improvements achieved using DPX fiber, the supporting lab data and field evaluation results.