70′ Zip Line from Free-standing Platform
September 22nd, 2009
Our launch platform is free-standing and constructed of pressure treated lumber (2 x 8’s, 6’s and 4’s) using galvanized fasteners (16d twist nails and heavy lag screws). The zip line uses a classic arresting block and 1/2 inch marine-grade shock cord anchored to a third tree (tangentially) to the main cable at around the 55-60 foot mark. We use separate shock cords for “kids” and “adults”. There is no landing platform as the arresting block and cable actually return the seat and rider to almost the initial contact point and riders simply hop off the seat. We are working on a seat return system as the next feature. Following a ride, we currently clip a line to the seat and walk it back up to the launch platform. Speed is good at maybe 15 or so mph. Despite the relatively short length the ride is exciting and pre-flight safety checks keep riders (the “thrillbillies”) healthy.
The zip line statistics are as follows:
Top anchor height: 12.5 feet
Lower anchor height: 8.5 feet
Cable length: 70 feet
The top anchor uses an 8 foot cable sling, pressure treated blocks on the circumference of the tree, galvanized fasteners, a 12 inch turnbuckle, and safety chain. The lower anchor uses the same blocks and cable clamps only.
Here are few photos and a sketch of the zip line:






































