Slicing, Dicing Abrasion Data

0

stanchion hole

Photos by Drew Frye

For testing, we used the same abrasion rig we used to test sewn eyes and rope (see PS March 2015). A modified wood lathe sawed line samples back and forth (a 3/4-inch stroke) at seven cycles per second through a 10-millimeter test stanchion hole. We tested each sample to failure, effectively condensing months or years of wear into just minutes.

During some trials, we held the chafe guards stationary in the hole, allowing the line to slide inside the guard; this provided the best protection against wear. We also tested each sample against a medium-grit, aluminum oxide grindstone hole, simulating a worst-case scenario. We compared these results with our experiences with polyester line and steel cable.

To test each rope or chafe materials resistance to side-to-side cutting, we passed each material sample through a saw-cut piece of stainless steel so that it exited at a 30-degree angle; then we attached a 100-pound weight to the end. To produce the sawing motion, we swung the weight like a pendulum through 30-degree arcs.

We tested three styles of stanchion hole: rough drilled with no finishing, finished with a counter sink and polished with emery cloth, and a hole that had been finished, but then grooved by running a rigging wire though it on an oscillating abrasion machine for 20 minutes.

In both cases, the holes were prepared fresh for each sample. Typically, most of the damage came early in the test, since the hole became smoother as testing progressed.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at darrellnicholson.com.