Before you can ever gaff a tuna you have to fool one into biting, and for many anglers the initial step will be building a spreader bar. When it comes to offshore trolling there are only two basic food groups: natural, and artificial. And one lure - the spreader bar - stands out as a staple. There are many different sizes and variations of spreader bars, not to mention different colors. But the charter fleet is partial to one in particular. Any spreader bar can catch fish, but if you construct the following bar, you will be dragging exactly what a large portion of the professionals have behind the transom.

tuna spreader bar lure
A 36-inch bar is used for construction, along with 14 six-inch “psycho” colored squid bodies and a Green Machine for the hook-bait. The measurements shown on photo are in inches and are measured from the bar to the top of the squid. The left and right sides of spreader bar mirror each other in dimensions.

These bars are generally pulled from a short rigger. Often, boats will have two spreader bars of differing colors in the water at once, one to either side. When the same bar gets multipel hits, number-two gets swapped out for the color of the day.

spreader bars for tuna trolling
The main leader is a single piece of 200-pound monofilament. This allows fish to be caught on a solid piece of line attached to the fishing line's swivel. The spreader bar is crimped to the main line with a short piece of 200-pound mono.
plastic squid lures
Using more of that 200-pound monofilament, construct squid lines by using crimps and beads (some mates use corks in place of beads; both work). The bead stops the squid body from sliding down the line and the crimp stops the bead. Measure carefully, so your squid are spaced according to the photo.​​​​​

In recent years many anglers have gravitated towards using corks instead of beads. The thought is that the additional buoyancy helps the bar stay on the surface, where you want it.

trolling lures for tuna
Once the squid lines are constructed, attach them to the spreader bar with crimps.
building a spreader bar
The last squid on the main line hides a snap swivel. Any artificial lure with a hook can be attached here, but a Green Machine is considered standard and is attached 95-percent of the time.

Editor's note: since this article was originally published the original Green Machine has gone in and out of production a couple of times. Today you'll see several very similar lures which include "Green" or "Machine" in the name and on occasion you can even find the original from someone who stockpiled them. Bottom line, as long as it's similar it still works just fine.

green machine tuna lure
The Green Machine (or other hook-bait) leader is 25-inches in length, from the snap swivel to the top of the Green Machine.
spreader bar for tuna trolling
Drag these spreader bars from your short riggers, far enough back that the squid are all in the water but the bar itself rides just above the water’s surface. You won't be disappointed!

Note that since this article was written, "Sidewinder" style bars have vastly increased in popularity and have replaced spreader bars on many boats. These track out to either side and can create more room in the spread behind your boat. However, they also can be quite finicky. Some roll under the surface with frustrating regularity, especially in rough water. Others tangle more often than regular spreader bars.

side tracking spreader bar for tuna
Bars that track to one side, like this Strike Point Outbound Rudder Bar available at Alltackle, have grown in popularity in recent years.

Another option is to pull splash bars, which have birds at the front to kick up a commotion. All of these can prove effective though some days one might out-catch the others. As for tactics and tips for fishing these lures, check out Spreader Bars for Tuna.

By John Unkart, the author of Offshore Pursuit and Saltwater Tales.

Editor's note: This article was originally published in January of 2018 and was last updated in August of 2024.