A New Spin on Dependable Crimps and Splices


A New Spin on Dependable Crimps and Splices

Our test focused primarily on the small-wire connections tensile strength, with and without solder, but we also looked at their durability under tough environmental conditions. We tested the pull-out strength without solder and the pull-out strength of soldered connections at 400 degrees by heating the connections in an oven to simulate overheating conditions. We tested fatigue by spinning a 6-inch length of splice wire at 650 RPM in a simple device that we called the wire-fatigue whirligig. Finally, testers soaked all samples for four months in salt water to accelerate corrosion, and then, we repeated the fatigue test.

Ordinarily, it would be good practice to cover all wire splices with heat-shrink tubing. Soldered splices definitely require heat shrink for insulation. However, for corrosion testing, we left them bare. We wanted to judge the connection, not whether the shrink seal failed. Heat-shrink tubing-adhesive lined for damp locations-is always good practice.

Testers also left the wire nuts bare; on land, where wire nuts are permitted, taping them is required when vibration is expected (motors, industrial settings), and some suggest filling the nuts with sealant on a boat. We doubt either method is fully dependable in a marine environment. We did use heat shrink in some of the fatigue tests, and in those cases, we used plain heat-shrink tubing.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. 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.


  1. Great research and write up. I always thought dielectric grease was good to use around a wrap before crimping, thereby filling all spaces to prevent corrosion. Can you comment about the use of dielectric grease?

    Ron W.
    Everett WA