The VOSI revisited

Jacob Cormier with a Catfish Lake trout taken on a Clouser Minnow suspended under a VOSI.

Dealing with vertically-challenged fish? Float on!

With Thanksgiving Day approaching, I’m compiling a list of the many things to be thankful for.

Somewhere on that list are speckled trout and sac-a-lait. I love catching both on fly rod as much as my family enjoys them at the dinner table — and November is prime time for both.

One of the best methods of catching either this time of year is with a lure under a cork. For flyrodders, the “lure” is a weighted fly, while the “cork” is a VOSI.

Fishing a fly under a float brings out my inner-child. But it also brings home dinner.

Making VOSIs
Making VOSIs simply requires perch floats, a sharp knife and a Dremel cone. Halves can also be used for poppers.

SO What is a VOSI?

Twenty-five years ago, I conceived an idea based on Pete Cooper’s Perch Float Popper. Pete took a Styrofoam perch float, cut it in half, then scoured out a concave face on the fat end using a Dremmel cone. After making a slit, the float was glued to a hook and painted.

My idea was to use that “half perch float” as a flyrodder’s popping cork. Simply slip it up a leader with the fat end facing the fly line, and insert the pin on the back end to hold it in place.

At the time, anti-cork sentiment in the fly fishing community ran high. So I named my creation the “Vertically Oriented Strike Indicator,” or VOSI (pronounced vo-see).

Over the 18 years I’ve done this column, the VOSI has been mentioned numerous times. And for good reason — its been highly effective for untold fly anglers.

Vertically-challenged fish

Long ago, the late outdoors writer Bob Scearce — popularly known as the Ol’ Beachcomber — explained why jigging lures was so deadly on speckled trout. He theorized that the up-and-down retrieve imitates a panicked baitfish, which then triggers a predatory response from the trout.

Likewise, fishing a lure under a cork also imparts a vertical motion to the lure when the cork is displaced. Whether it’s a tube jig for crappie or Sparkle Beetles for trout, the result is more bites than a straight retrieve.

That same principle applies to weighted flies suspended under a VOSI. The only explanation I have is that some fish are vertically-challenged.

Speck guidelines

I tell folks there’s a 37-page operations manual on using a Vertically Oriented Strike Indicator. Of course that’s a joke. The manual is only six pages ­— but I’ll try and condense it to a few paragraphs.

For specks, a weighted fly — like a Clouser Minnow or EP Shrimp — is suspended below the cork, usually 2 to 3 feet. It’s important that before any retrieve is made, the fly falls to its maximum depth.

When this happens, the cork will be slightly tilted, as opposed to sitting horizontally on the water. At this point, make a short jerk of the rod tip. I know that violates the principle of “strip popping,” but trust me, this works better.

After each jerk, retrieve the small amount of slack. Let the cork sit a couple of seconds as the fly descends. Countless trout have been caught on this pause.

Crappie guidelines

Flyrodders have long used football strike indicators for crappie. But those indicators are pretty pricey — about a dollar each.

My buddy Randy Leonpacher determined it was a lot cheaper to use VOSIs. What he also noticed was that the crappie needed a more subtle presentation, so he inverted the VOSI — placing the narrow end facing the fly line.

Crappie love structure, and won’t venture far from it. A VOSI and a dropper fly (e.g, Fluff Butt) allow the angler to stay in the bite zone longer. For this reason, the retrieve calls for tiny strips and longer pauses.

With sac-a-lait, be aware of any suspicious movement of the float. The tiniest bounce may be a bite, so raise the rod tip and set the hook.

Perch float selection

The two most common perch floats used are both 1 ½ inches long. One is 3/8-inch diameter, the other ½-inch.

The narrower floats are easier to cast, but are limited to weighted flies 1/40 ounce or less. They’re also limited to calmer conditions.

The wider floats can handle heavier weighted flies and pop better in choppy water. But they’re also more difficult to cast on lighter rods.

When slicing a float in half, I usually put the white ends aside to use for Perch Float Poppers. If you decide to use these for VOSIs, I suggest coloring them with an orange permanent marker for better visibility.

Other tips

A VOSI does not work well on a heavy leader. I use a light three-section leader (butt, midsection, tippet). The butt is usually 20 pounds, tapering down to a tippet of 12 pounds for salt, or 8 pounds for fresh.

I also get better results if the tippet is long (3 feet max), and the float and fly are on that same section.

As mentioned in the May column, VOSI setups are best cast with a more open loop, or a Belgian Cast to prevent tangles.

VOSI setups do not work well in very clear water. Speckled trout will often attack the float instead. When that happens, switch to a popper.

Catch Cormier
About Catch Cormier 271 Articles
Glen ‘Catch’ Cormier has pursued fish on the fly for 30 years. A certified casting instructor and renowned fly tier, he and his family live in Baton Rouge.