During the quarter-finals of our last competition our Pilot looked out over the field and noted that 3 of the teams of the field were using our climbing ropes, one of which was on the opposing alliance. After seeing so many posts about ropes failing in competition, 2363 has decided to share our method for making ropes with the FRC community.
Materials:
Solid braided rope from West Marine, 5/8" diameter.
3mm Spectra Speargun line
Plain backed loop side velcro
Upholstery thread
tape
Tools:
Scissors
long, pointy stick
sewing machine
Instructions:
Watch the instructional video we put together last night.
The length of the spectra rope will be specific to each team’s robot and climber. We use three knots in our rope: the figure 8 knot in the spectra, that keeps the core from pulling through the big knot; the big figure 8 knot, that rests on the davit fingers; and a slip knot just above the velcro patches, that allows a couple wraps around the climber shaft before starting to climb. Each of these knots consumes a surprising amount of rope length. You can figure out how much for yourselves, experimentally. If you are using some other type of loop knot at the bottom of your rope, be sure to use a version that’s suitable for spectra rope. Spectra is very slippery, and knots that work with other types of rope will pull out of spectra rope. As noted in the video, the only failure of our rope was one match where the spectra rope pulled through the big figure 8 knot. After that we added the stopper knot to the spectra above the big knot.