What it is
Hareline Polypropylene Yarn is a floating yarn made from polypropylene, built out of many fine fibers. It’s lightweight and buoyant, and you can pinch off more or fewer fibers to dial in the amount of bulk you want without changing materials.
What to tie with it
Use it for parachute posts, upright dry-fly wings, spinner wings, terrestrial wings, and emerger wings, where that floating fiber helps keep the fly up in or on the surface film. It also works well as a visible strike indicator material, and tyers commonly use it as an underwing on Elk Hair Caddis-style dries to add float without adding much weight.
Flies and the fish they're for
Tie it into Parachute Adams-style dries as the parachute post for trout on rivers and spring creeks, where the fly needs to stay riding high and easy to track. On mayfly spinners like a Rusty Spinner, it makes clean, splayed wings for picky trout feeding in slick tailouts and calm flats. As an underwing on an Elk Hair Caddis, it supports a classic caddis adult imitation for trout in riffles and pocketwater.
How it compares
Compared with Antron yarn, polypropylene yarn is more buoyant and tends to suit patterns that need to sit in the surface film and stay afloat.
