Double Line Deconstructed

Rigging with reliable knots is a vital lesson every fisherman learns early on in their angling career. Sadly, most learn the lesson of poorly tied knots the hard way. If you think about it, of the many variables that we have zero control over while fishing, tying strong and reliable knots is one key to success that literally rests at the tip of our very own fingers. Nowhere is this lesson more important than in the pursuit of top tier blue water pelagics. Billfish and tuna are powerful predators capable of tremendous bursts of speed and are notorious for exploiting any weak link. The solution? Rig like a pro and don’t allow tackle failure to ruin your big day.


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Steve Dougherty

Double lines—which essentially increase the strength of the working end of any running line—are just one of the many crucial connections that play an important role in big game rigging applications. Among the numerous benefits, including increased knot strength and chafe protection, double lines enable anglers to fish streamlined wind-on leaders, which greatly simplify dangerous wiring duties. But which double line knot maintains maximum breaking strength when it matters most? Is it the popular Bimini twist that is consistently used in the ‘pit by big game crews worldwide? Is it the 10-second spider hitch, or the simple surgeon’s knot?

What we witnessed with our own eyes and recorded on paper actually proved what we suspected all along.

Using Diamond Hi-Catch 50 lb. monofilament—which consistently over-tested and broke just above 70 pounds of pulling power—and a calibrated line testing machine courtesy of Pompano Beach’s Lindgren-Pitman, a global leader in commercial fishing equipment, we put three popular double line knots to the test. While we didn’t calculate precise scientific measurements using computer generated formulas and military spec micrometers, the entire testing protocol was consistent across the board with results averaged from an identical number of independent tests utilizing the same criteria. What we witnessed with our own eyes and recorded on paper actually proved what we suspected all along.

I don’t want to bore you with the details, but I will tell you that the spider hitch performed above the line’s rated breaking strength, although it consistently failed at an average of 54 pounds of pulling power prior to the running line parting. The surgeon’s knot had the worst showing of the three and broke at an average of 32 pounds of pulling power, far below the line’s rated breaking strength. The results speak for themselves and with either of these double line connections, the first component to fail was the knot.

On the other end of the spectrum, the 20-turn Bimini twist exceeded our expectations. The famed Bimini twist trusted by blue water anglers in all of the world’s oceans was the only double line connection that consistently surpassed the line every time! To be clear, the 50 lb. test mono broke at over 70 pounds prior to the knot failing. That was enough data to convince me that when it comes to reliable offshore double line connections, it’s the Bimini twist or bust!