Looks can be deceiving. Take the nylon lines you've been using as an anchor rode or to tie up at the dock. They are not new and they look a bit beat, with chafing where the lines left the chocks or tied to the cleats.
But they still hold. Or do they?
Practical Sailor and BoatU.S. put such line to a test. It didn't do well.
"We always knew used nylon line wasn't as strong as new," says Bob Adriance, technical director at BoatUS "All of the older lines had lost between 50 and 75 percent of their rated strength over new lines.
"That's incredible."
In real-life terms, that means a 1-inch line securing a boat – far larger than most of us use – now has the strength of a ½-inch or ¼-inch line. But, Adriance says, it gets even worse.
Compression takes away half of nylon's strength. Lots of back and forth, during a storm for example, creates heat that can cause nylon line to fail internally. Putting PVC around the line only makes things worse during a storm, because water won't reach the line to cool it down.
And the test involved dry, weathered, three-stand nylon that was 12 to 15 years old. Wet nylon loses even more of its strength.
"It can't handle the stresses," Adriance says. "If I was going to tie my boat up (for a storm) I would want new line, whether it is at a dock or in a mooring."
Pam - This is really great stuff! When they were doing all the line testing, did they include braided as well as stranded lines? I'm just curious about how all sorts of different lines would fare.