Despite continuing mechanization, harvesting timber places high demands on lumberjacks and materials. This also applies to the ropes used in hauling and winching the timber, leading fibre manufacturer Dyneema reports.
In Austria, both the Archbishop office of Vienna and Ernsthof Forstverwaltung are among a growing number of forest owners who rely on fibre as opposed to steel wire ropes for reasons of ergonomics and safety.
Between them, the two harvest around 25.000 m3 of timber annually and both are recipients of the prestigious State Award of Role Model Forest Management, granted by Austria’s Federal Ministry of Agriculture, Forestry, Environment and Water Management.
For hauling the logs, both forest holders have been using advanced winch ropes made with Dyneema® for more than five years. Dyneema® is DSM’s brandname for its extremely tear and splice resistant fiber of high-modulus polyethylene (HMPE). The typical application comprises a tractor with fixed hauling equipment, including a rope winch providing a traction force of up to 10 tons.
The patented forestry ropes are manufactured by Teufelberger Company and marketed under the STRATOS® Winch Pro brand. To avoid the core rope that bears the traction force becoming frayed, particularly on rocky terrain, Teufelberger covers the Dyneema® core of its STRATOS® winch ropes with an especially tight Dyneema® braid. With this rope design, even the medium-sized 15 mm diameter STRATOS® Winch Pro rope (12 mm core + 3 mm mantle) is rated for a minimum break load of 160 kN and a splice resistance of 150 kN.
STRATOS® Winch Pro ropes have proven to be an extremely rugged, lighter and safer alternative to conventional steel wire ropes. A key argument is their lower weight: “It makes a big difference in time and labor, whether two or three lumberjacks must pull a 100 kg steel rope uphill, or whether the same work can be done with a fiber rope that weighs only 12 kg.” says Alfred Steiner from the Feistritzwald district management of the Vienna Archbishopric.
With these fiber ropes, research shows timber can be harvested up to 20% faster, increasing productivity. Furthermore, forest engineer Martin Exenberger from Ernsthof Forstverwaltung emphasizes the higher safety in case a rope should unexpectedly fissure: “Steel ropes, when torn apart, will snap out of control, whereas the synthetic rope will simply fall down without any spiky or broken wire strands. The risk of injury is significantly reduced.” Moreover, experience has shown that the winch ropes with Dyneema® last two or three times as long as the former steel ropes.
Erich Rührnößl, development engineer at Teufelberger in Wels, Austria, highlights the company’s many years of collaboration with DSM Dyneema onseveral rope projects. “Before introducing STRATOS® to the market, we executed comprehensive abrasion, breakage and tensile strength tests in order to make sure the fiber ropes will at least provide the same performance that our customers expect from wire ropes – however at significantly lower weight.“
Teufelberger supports its forestry customers with tailor-made accessories, such as special rope end bonds that prevent the winch rope from being pushed off by twitch hooks, thus effectively protecting the rope cover along the entire length of the rope. Patented splice end bonds permit fast on-site repairs, which is of major importance particularly at low temperatures in winter. For its STRATOS® Anchor guyline rope developed for yarders, the company was honored with Austria’s State Award for Innovation.
Dyneema® is 15 times stronger by weight than quality steel and up to 40 percent stronger than aramid fibers. Its minimum break load excels that of steel wire and other synthetic fibers. Dyneema® floats on water, is resistant to moisture, UV irradiation and chemicals, and has been OEKO-TEX® certified. Its application potential is therefore more or less unlimited, including but not limited to: fine yarns for sporting goods as well as light body armor, winches and nautical ropes.