Crimping on Mono and Cable

The art and science of crimped connections

December 3, 2015
crimping tactics

Crimping Insights

Crimping insights Zach Stovall

A professional crimping job decides whether you and the crew celebrate an incredible catch or partake in a long, depressing ride back to the dock — and we’ve all been on both sides of that coin. As basic as crimping seems, the “art” is anything but elementary. ­Selecting the correct sleeve and material, sizing it to the leader and properly executing the connection are crucial. To keep you and your next big fish from parting ways unexpectedly, heed the insights that follow.

Hand swagers stow easily and handle a variety of crimping chores on mono and cable. File Photo


The objective of ­crimping, beyond forming loops and attaching hooks, is to compress a leader and meld it with the sleeve ­without damaging it. Read: zero slippage. Hence, it is critical to size the sleeve diameter to the leader.

Rick Mola, noted canyon angler and head of ­Fisherman’s World in Norwalk, Connecticut, says it’s impossible for sleeve manufacturers to offer a precise sleeve for mono or fluorocarbon leader in every specific pound-test due to their differing diameters. Therefore, sleeves are grouped into broader categories, such as ­1.3-millimeter sleeves for 150- to 200-pound-test mono and ­1.6-millimeter sleeves for 220- to 250-pound-test.

hook for fishing
Thimbles and plastic tubing, commonly used as buffers to prevent wear from the leader rubbing against the hook eye or the snap swivel, may just save you a large fish. Without anti-chafing gear, Mola says a hook may literally “melt” off the leader due to intense friction during the long, sustained run of powerful fish such as tuna. Tim Barker

Mola recommends the smallest diameter sleeve through which the leader can pass, albeit tightly, versus a sleeve that is slightly larger and easier for the line to navigate. The latter has more ­slippage potential. When purchasing sleeves, Mola suggests bringing in your leader material (if not purchasing it at the same time), opening a pack of sleeves rated for that pound-test leader ​and actually fitting the leader into the sleeve. Sometimes a recommended sleeve size doesn’t fit ­precisely. It’s like trying on a pair of shoes before you buy.

“Sometimes the diameter of your leader falls between two sleeve sizes,” Mola says. “If your 200-pound mono has a diameter of ­­1.48 millimeters, a ­1.3-millimeter sleeve will be too small for that line. You’ll have to move up to the next size; in this example, ​a ­1.6-millimeter sleeve. Then the proper crimping ­procedure becomes even more ­important.”

crimped connections
Working a mono or fluoro leader through the correct-size sleeve can be challenging due to the tight fit. By cutting the leader at an angle to reduce its initial diameter and then moistening it with saliva, it should penetrate the sleeve easily. Prior to crimping, leave a short tag end. After crimping, heat the tag end with a lighter and blunt the end. In case of slippage, extra width in the tag end will jam against the sleeve. Tim Barker


The best-selling ­saltwater sleeves are the oval, ­double-barrel designs. Round sleeves are less ­reliable on heavier leaders.


With a double-barrel sleeve, popular for monofilament and fluorocarbon ­leaders, each leader strand rests snugly within its own chamber. The chance of the leader laying over itself is eliminated (ditto with related damage). Scarring of the leader during the ­crimping process is also greatly reduced, providing it’s done correctly.

Double-barrel sleeves are also popular with cable rigs due to the exceptional bite the two metals generate. More on specific cable sleeves in a bit.

Oval sleeves are ideal for fluorocarbon leaders because fluorocarbon is more oval-shaped than round in diameter. Ovals often get the nod for heavier fluorocarbon as well as rounder nylon mono leaders used for big-game fishing (large marlin, swordfish, tunas and sharks), but they also serve well for lighter leaders for small game.


One caution with oval sleeves: Make certain the leader does not lay over itself prior to crimping.

fishing knot
When crimping multistrand wire or cable leaders, opt for zinc-plated brass sleeves and always bury the tag end inside the sleeve. Tim Barker


According to Jack Butts from Rosco Terminal Tackle, there are only two metals used for crimps: ­aluminum and brass. “Nickel, zinc and black oxide are plated finishes ­applied to brass sleeves,” Butts explains. “These two metals are favored over stainless steel because they are softer and less likely to damage the leader. Brass and aluminum will not react with the salt water and, therefore, won’t pit or corrode.”

Big-game angler Jeffrey Liederman of Capt. Harry’s Fishing Supply opts for zinc-plated sleeves versus aluminum with cable leaders to prevent electrolysis from the two metals like a zinc anode does on an outboard. For mono and fluoro, both Liederman and Mola are proponents of aluminum ­because it shapes best to those materials and provides the snuggest fit.

double-sleeving on crimp
Double-sleeving is like an insurance policy, but is it worth the effort? If a crimp fails, that backup sleeve could very well save the day. Double-sleeving is also useful for putting space between a hook eye and a lure, like a trolling feather. When creating space this way, add a plastic bead between the lure head and the sleeve closest to the lure. This slight bit of extra space between the sleeve and lure prevents binding, plus itallows the hook to lay properly. Tim Barker


Oval and double-barrel crimping tools are designed with round dies for multiple sleeve sizes. Crimpers with a notch are designed for round sleeves. Mono up to 200-pound-test is easily crimped with a hand swage, whereas a bench swage is more precise for leaders over 200 pounds. Avoid crimping near a sleeve edge. The end of a properly crimped sleeve flares, whereas crimping at the edge crushes the metal into the leader, weakening it. Based on the length of the sleeve, more than one ­compression can be applied for extra insurance.

On cable, ­crimping the bitter end of a sleeve ­prevents slippage. ­Liederman compresses the tag end and flares the end facing the hook.

sleeves on crimp
Long, thick-walled sleeves are intended for the heaviest tackle. When light-tackle trolling for white marlin, sailfish or dolphin, select short, thin-walled sleeves. They’re unobtrusive and also help preserve the action of small baits and lures. Tim Barker


Mola won’t let any crimped system out of his store without a final test: a heavy-duty screw affixed to a desk. He simply attaches the con­nection to the screw and applies pressure. Any weakness reveals itself at this stage. Better here than when slugging it out with a heavyweight fish. After all, everyone enjoys a festive boat ride back in, especially when there’s a big fish laying in the cockpit or a release flag flying from one of the outriggers.

blue marlin caught in Brazil
Big-game tackle demands reliable connections in the terminal rig. George Poveromo
blue marlin caught in brazil
Extreme pressures during the end game put leader connections to the test. George Poveromo

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