From an article by U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) Communications Staff
Marines at Camp Pendleton, California recently conducted field user evaluations to test the performance of a lightweight synthetic winch rope, which could represent a major shift in a business based for decades in chains and cables. Members of the U.S. Marine Corps’ (USMC’s) 1st Light Armored Reconnaissance battalion conducted the evaluation with the Light Armored Vehicle Recovery (LAV-R) variant and its new winch. The Marines responded positively to the winch rope’s light weight, ease of use, and readiness for fielding.
The high-performance winch rope was developed as part of a co-development project between Samson and Warn Industries of Clackamas, Oregon—manufacturer of vehicle winch systems. The goal was to develop a new lightweight vehicle winch system specifically for military recovery vehicles.
Wire winch cables currently mounted in recovery vehicles weigh around 200 pounds, require four to six people wearing protective gloves to move it to disabled vehicles, and are coated with a messy lubricant.
A 25-pound synthetic winch rope can be toted to the same disabled vehicle by one person in about 30 seconds, and the gloves are optional. Because the synthetic rope requires only one or two crew members for set-up, fewer people would be exposed to enemy fire during a vehicle rescue in combat areas.
"The current wire cable takes five guys about seven minutes to prepare a vehicle for towing,” commented Mark Weaver, Project Manager-LAV Sustainment. “With the synthetic rope, one Marine took 27.5 seconds with the same length of rope—about 165 feet. The regular cable has to be rolled back onto the drum [after rescuing a vehicle]. One man can throw the synthetic rope in the back of the vehicle and drive away—like a hose or an electric cord —if they have
to leave quickly.”
Members of a USMC LAV-R crew tried out the new rope during a User Jury at the Detroit Arsenal last fall and found it more effective to use in recovery missions. “It’s a lot lighter and easier to handle,” observed Gunnery Sgt. Chris Manning. “You don’t have to worry about frays or kinks, you don’t have to worry about keeping the dirt off it.”
The LAV-R winch performance specification document states that the system must be strong enough to recover a vehicle mired up to the middle of its wheels and weighing up to 38,000 pounds, but Weaver says the engineering team designed the winch and rope to pull up to 60,000 pounds (using a snatch block to achieve a 2:1 mechanical advantage).
“We know the new rope with the same diameter will withstand the force and we’re confident it can function beyond the capacity of the current cable,” Weaver noted.
In addition to the extreme light weight, ease-of-use, and strength benefits, the synthetic rope also offers unique safety advantages: It will not unwind and whip if it breaks, and broken strands do not form dangerous fish-hooks to injure handlers as wire cables do.
When wire cables part, the severed ends of the strands fly out from the break in a helix-like pattern. “A broken wire spinning like that could cut right through your hand. Our rope just drops if it’s broken. There are no spin tendencies in the synthetic rope and no similar risk of physical damage.” Weaver explained.
The synthetic rope is a jacketed 6-strand construction of 100% Dyneema® HMPE. The jacket protects the strength member from abrasion and adds firmness for better spooling on winch drums. It weighs approximately 85% less than an equivalent size of wire rope with the same strength.