CASE STUDIES

PowerSeat® Ascender Used to Move Heavy Loads of Wood in Challenging Terrains

Business Segment: Arborist

Location: Brevard, North Carolina, United States

Project Description: An age-old question: If a tree falls, and there is no one around to hear it, does it make a noise?

The answer is more than a simple, ‘yes’.  If you were to get to know Aaron Bailey, a furniture maker based in Brevard, North Carolina, you would begin to understand that certain trees command more attention than just listening when their time comes to an end.

Recently, Aaron was contacted about removing an exemplary black walnut tree from very challenging terrain. The tree was located one-third of a mile from road access, with a vertical gain in elevation of nearly 183 m (600′) through a storm-damaged valley, covered with flowing springs and downed trees.

Aaron, a rigger and certified rope-access technician, took the challenge head-on, knowing that the right rigging tools would do the job. Heavy machinery was not an option because of the water flow and environmental damage it would cause. A team of horses was considered, but safety in such steep terrain was a concern.

The goal was to have two men, using rope-rigging techniques, move multiple sections of .91 m (36")-diameter logs to road access, where they could be reached with a crane truck and hauled to the mill. Each log averaged 3 m (10') in length, for an estimated weight of 1134-1361 kg (2500-3000 lb).

Solution/Equipment Used: The Harken Industrial PowerSeat was used as a fixed-point hauling system and mechanical advantage was added to the system with a variety of Harken Industrial™ pulleys. A Black Magic® 125 mm Air® pulley, with industrial Snatch pulleys, and a IN1540 Midrange block was used as the basis for the mechanical advantage system.

A Sampson True Blue all-polyester 12-strand, single-braid rope was tested. Some slippage on the winch drum was expected with this type of rope, but the winch has plenty of purchase once the rope compresses under tension. A series of ‘leap frogging’ maneuvers was used, going from tree-to-tree, anchor-to-anchor, changing the mechanical advantage along the way. The PowerSeat haul line was used, with 2:1, 3:1, and 4:1 MA (mechanical advantage) systems. The systems worked repeatedly and as desired, with a functional smoothness that had the crew eyeing the crags for other large valuable timber.

Summary: The PowerSeat performed admirably while being used as a portable powered winch to haul lumber through tough terrain.

These Harken Industrial products were featured in the case study above: PWRS-G, IN3256, IN1540