If you use crimped connections in monofilament line or leader, you may be in for a shock. When I started using mono instead of wire for my trolling leaders almost 30 years ago, I tested some mono against wire to see which was stronger. What I discovered went beyond the arguments about which leader material to use; my tests revealed how difficult it is to make good crimped connections.
When I tested several brands of line and a variety of sleeves and crimping tools, what appeared to be good, solid connections failed at a mere 40 percent of the leader's breaking strength. Recently, I did more extensive testing, which proved even further just how precise you must be to make the perfect crimp.
How important is that? If your leader is much heavier than your line, even a 40-percent crimp may be good enough. The line usually will break before the leader snaps or the crimp fails. However, when mates wire a fish at the boat and greater strain is placed on the leader, that crimp connection becomes more vital. Similarly, if you lighten up on your terminal tackle for leader-shy fish, anything less than a 90-percent crimp may mean an instant break-off.
Hold Tight and Pull
In 1975, Capt. Jim Hunter and I sat down at his house in Kona, Hawaii, with a six-pack of beer, a small stainless-steel shackle, a metal ring about 2 inches in diameter and a huge screwdriver. We also had coils of 250- and 300-pound-test monofilament leader and a variety of sleeves. Our crimping tool was an old one, the one-size-fits-all type with a semicircular notch in one jaw and a blade on the other, which compressed the sleeve around two strands of line.
We sat on Hunter's floor and anchored our leader at the base of a wall to test a variety of crimped connections. With straight legs and back, we could pull hard enough to break the 300-pound leader and even some 0.035-inch-diameter wire -- both stainless-steel (240-pound test) and tinned music wire (330- to 350-pound test). We used the large screwdriver as a handle to pull on a loop in the leader material. (Pulling with the leader wrapped around gloved hands was too painful to make multiple tests!)
We never knew the exact breaking strength in pounds, but we could generate some conclusions by how hard we strained to break the test sample. We could compare two different sleeve sizes, our individual crimping techniques, or even the strength of piano wire versus monofilament. We attached pieces of each leader to the metal ring and pulled at opposite ends.
The simplest test involved crimping a loop at either end of a 2-foot piece of mono. We shackled one loop to the wall and pulled on the other loop with the screwdriver until something gave way.
Our comparison test demonstrated three outcomes:
- A sleeve would slip, and the line would either slide free or would slide and then break because the sleeve was not crimped tightly enough.
- The line would break inside one of the sleeves because it was overcrimped.
- The line would break outside the sleeves, indicating two perfect crimps.
Hunter and I used the same crimping tool, but for several hours Hunter's crimping technique beat me every time. ''You have to squeeze until [the crimp] feels hard, but not too hard or the line breaks inside the sleeve where it gets damaged,'' he would tell me.
Hunter would occasionally achieve the perfect crimp, but I never really did. Especially in the beginning, mine either slipped or broke in the crimp. Once I began to get the feel for how hard to squeeze the crimping tool, it took a lot more strain to break the line. But getting a feel for proper crimping pressure is not something quickly and easily taught to a new mate.
