I've been investigating chafe protection and Amsteel as it relates to lifeline replacement. Certainly, wire cable is the gold standard. But now I'm not so sure....
After an hour of sawing back-and-forth through a 10mm hole in SS tubing, it had eaten a nice groove and built a corresponding burr on the inside:
After 1 hour.
And though the wire did not look very worn, when we flexed just a bit there was a different story....
Also 1 hour. The damage was not apparent until flexed. Most of the broken wires were inside.
How did Amsteel fare, in the same hole? Before the wire created the burr? Much better with very little wear in an hour. Afterwards, no as well, but still the damage was little more serious than that to the stainless cable. Given that I plan to use 1/4 Amsteel, which is nearly twice as strong as the cable to start with, I'm feeling OK. 1/4-inch it is sufficiently strong that even after 10 years in the Chesapeake sun (not so strong as the desert southwest or tropics) it should have equivalent strength, and with proper chafe guards, the strength loss in the holes should be less than wire. Protected from the sun, the pass-troughs may be the strongest part by then.
How does Amsteel like the new hole? Not so bad as you might think and about the same as it like the raw hole, just after I drilled it without deburring. By way of comparison, after the hole was deburred it showed ~ 1/3 this much wear, and if coated with Spinlock RP25, no wear after 2 hours (840 cycles).
After 1 hour on the wire cable gouged hole. About the same as a raw drilled hole, yet much worse than a polished hole.
Alternatively, I tried a dyneema anti-chafe sleeve floating for 3 hours. It could have run for 100 hours without showing wear.
A floating dyneema cover reduces wear to zero.
By way of comparison, this hole wore a polyester line through the cover in 20 seconds and in half in 5 minutes. Amsteel is tough stuff.
Thursday, May 15, 2014
Over at Sail Delmarva Drew puts the test equipment he has built to work investigating the ability of various recommended lifeline materials to resist chafe thru the stanchions...