Scientific Anglers Sonar Stillwater Sweep Parabolic Sink 3/5/3 Fly Line
The Scientific Anglers Sonar Stillwater Seamless Density Parabolic, commonly known as a Sweep line, uses three different densities to create a U-shaped profile through the water. Its Sink 3 / Sink 5 / Sink 3 construction allows you to search different depths during a single retrieve while maintaining good contact with your flies.
- Parabolic or “Sweep” style sinking line
- Sink 3 / Sink 5 / Sink 3 triple-density construction
- Creates a U-shaped profile through the water
- Designed to search different depths during the retrieve
- Seamless Density technology provides smooth transitions between densities
| Specification | Detail |
|---|---|
| Line Type | Parabolic (Sweep) Sink |
| Density Construction | Sink 3 / Sink 5 / Sink 3 |
| Profile Shape | U-shaped |
| Design Purpose | Search multiple depths during a single retrieve |
| Technology | Seamless Density |
FAQ
What is the benefit of the Sink 3 / Sink 5 / Sink 3 construction?
The triple-density design creates a U-shaped profile that allows the line to search different depths during a single retrieve, improving the ability to locate fish across varying water levels.
How does the Seamless Density technology improve performance?
Seamless Density technology ensures smooth transitions between the different densities, reducing abrupt changes in sink rate and improving line stability and fly contact.
Is this line suitable for stillwater fishing?
Yes, this sweep line is specifically designed for stillwater environments where depth variation and consistent fly contact are important.


Julian Gill –
This sweep line performs well in quiet lakes. The U-shaped profile helps me cover multiple depths without losing fly contact. The transition between densities is smooth and feels natural during casting and retrieval.
Deirdre Campbell –
I’ve used it in a variety of stillwater conditions. The Sink 3/Sink 5/Sink 3 design allows me to search deeper areas without adjusting line frequently. It’s a reliable choice for cover fishing.
Boris Vance –
The seamless density construction makes a noticeable difference. I can feel the line moving smoothly through the water, and my flies stay in contact better than with standard sinking lines.