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  • Writer's pictureJon Osborn

Gear Review: Scientific Anglers Sonar Trout Express Sink Tip Line

Updated: Mar 7

bamboo fly rod with reel and fly line


Specific situations call for specialized gear. To wit, small streams choked with encroaching vegetation require a different setup than wide rivers with infinite back-cast real estate.

Scientific Anglers’ “Trout Express” series was specifically designed for delivering small streamers on rivers where casting is questionable. These sink-tip lines are available in weights from 165-grain all the way up to 320 grains – which in layman’s terms, corresponds to rod-weights between 4 and 10.

It’s a catalog that offers plenty of options, but I wanted a five-weight setup for casting streamers in small water. Doubtless, a five-weight rod is normally considered light for streamers, but “normally” is the operative word, in this case.

I was looking for versatility.

Since small streams typically receive some of the lightest angling pressure, they often harbor some of the largest trout. However, these trickles are often crowded with clutching branches and high grass, which present casting challenges. In such places, a heavy setup can feel like overkill – even if the resident trout run big enough to warrant carrying a seven or eight weight rod. Secluded spots like these are ideal for a stout five-weight rod equipped with floating and sinking line options.

Scientific Anglers’ Trout Express sink tip sports a 105-foot overall length, with a 29-foot head, specially designed to roll cast chunky streamers in congested settings. Not full-size Sex Dungeons with massive lead eyes or bulky, seven-inch Circus Peanuts, but smaller options, like Pine Squirrels, Marabou Muddler Minnows, and Wooly Buggers.

*Disclaimer: I’m confident a heavier sink-tip line paired with a stouter rod would cast larger streamers with ease, but the subject of this review is the 185-grain version, which was made for 5-6-weight lines.

healthy wild brown trout caught fly fishing

The Proving Grounds:

Michigan Small Stream, Early April

Outfit Overview:

Fly Line – Scientific Anglers Sonar Trout Express 185-grain Sink Tip

Rods – Nine foot, 5-weight graphite

Reel – Orvis Battenkill Bar Stock II

Flies - #6 mini–Sex Dungeon

My first chance to fish the SA Trout Express line arrived on a cloudy Saturday morning in April, on a favorite unnamed Michigan stream. Early in the season as it was, the leaf cover was minimal, but multi-flora rose bushes and nodding tag alders bordered the banks. The water there runs approximately 25 feet wide, with a three-foot average depth, pockmarked with occasional eight-foot holes.

That day, the river was running high and off-color, making wading difficult, which may have explained why no other anglers were present. Thankful for the solitude, I knotted-on a black mini–Sex Dungeon and began creeping along the banks. Roll casting was my only option, but how far would that technique deliver a waterlogged streamer? I doubted very far. To my surprise, casting was fluid and there was energy to spare in most cases.

Working downstream, I flipped the Dungeon toward the opposite bank, twitched it once or twice, and began stripping it back. It wasn’t long before a buttery, foot-long brown rushed out and shook the streamer like an angry terrier. Buoyed by the early success, I resumed roll casting toward other likely spots. A few minutes later another trout flashed from the depths and put a serious bend in the little five-weight rod. To my surprise, this fish was even larger, measuring over 15 inches. And that’s how the entire morning continued – constant action from chunky brown trout. Not a bad way to spend a Saturday in early spring.

traditional fly fisherman chasing trout in the Driftless region

Wisconsin Small Stream in Early Summer

Outfit Overview:

Fly Line – Scientific Anglers Sonar Trout Express 185-grain Sink Tip

Rod – 7’09” 5-weight bamboo

Reel – Orvis Battenkill Bar Stock II

Flies - #8 Pine Squirrel

Months later, I had another opportunity to test the Trout Express line – this time around Wisconsin’s Driftless Region. The conditions that day were polar opposite from my initial experience in Michigan.

Most of the Wisco streams we had intended to fish were off limits. The area hadn’t seen rain for months, and flows were warm and anemic. After driving around for hours, we finally found a river worth wading, but our Hippy Stompers and caddis imitations were met with snooty indifference. Trekking deeper into the woods, however, several deep, shady pools looked like enticing spots to cast streamers.

However, like many small rivers, the surrounding flora presented a challenge. The vegetation was comprised of high, grassy banks and overhanging box-elder branches. The water ran approximately 25 feet wide, with an average depth of two feet with occasional four-foot holes. Driftless streams stereotypically gurgle through a pastoral landscape, and this one was no different. The fertile flows were clouded with ag runoff from the surrounding crop fields and herds of wandering cattle.

Instead of graphite, I was carrying a bamboo rod that day. Since the fish weren’t interested in dry flies, I swapped my floating line for the sink tip and went to work. I’m pleased to report that the Trout Express line performed just as well on a wood rod. The resident brown trout attacked the streamers with reckless abandon.

The Driftless Region isn’t known for slab-sided brown trout. Sure, a few lunkers live there, but anglers visit for the bucolic landscape and consistent dry-fly fishing, and most trout run between 8 -12 inches. That said, my best brown that day exceeded all expectations. He’d been sulking along the bank, unseen until he swirled at an olive Pine Squirrel streamer, twitched downstream and across. In the net, that fish measured 16 inches.

releasing a brown trout caught on a fly rod

What I Like:

The short, rear-weighted head that excels at roll casting large streamers in tight spaces is the greatest feature of the Trout Express Sink Tip line. That said, I appreciate the two-tone coloration (sky blue with lime-green running line) and the fact that the line-specs are printed directly on the line.

trout stream in Wisconsin's Driftless region

What I Don’t Like:

Getting tangled up in tag alders, but that’s an inevitable factor of fishing small streams, no fault of the line itself.

traditional bamboo fly rod and reel with scientific anglers line

Value: As Jim Harrison’s artist/angler buddy Russell Chatham once noted, fly line (not rods, reels, or flies) is the most important piece of gear in a fly angler’s quiver. Viewed from that perspective, dropping a Benjamin for a spool of Trout Express seems like a steal.

Perfect For: Small streams where roll casts and small-sized streamers are the norm.

Stars: 5 out of 5.

Learn More about the Scientific Anglers Sonar Trout Express sink-tip line here.

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